Class FileUtils

java.lang.Object
org.apache.commons.io.FileUtils

public class FileUtils extends Object
General file manipulation utilities.

Facilities are provided in the following areas:

  • writing to a file
  • reading from a file
  • make a directory including parent directories
  • copying files and directories
  • deleting files and directories
  • converting to and from a URL
  • listing files and directories by filter and extension
  • comparing file content
  • file last changed date
  • calculating a checksum

Note that a specific charset should be specified whenever possible. Relying on the platform default means that the code is Locale-dependent. Only use the default if the files are known to always use the platform default.

Origin of code: Excalibur, Alexandria, Commons-Utils

  • Field Details

    • ONE_KB

      public static final long ONE_KB
      The number of bytes in a kilobyte.
      See Also:
    • ONE_KB_BI

      public static final BigInteger ONE_KB_BI
      The number of bytes in a kilobyte.
      Since:
      2.4
    • ONE_MB

      public static final long ONE_MB
      The number of bytes in a megabyte.
      See Also:
    • ONE_MB_BI

      public static final BigInteger ONE_MB_BI
      The number of bytes in a megabyte.
      Since:
      2.4
    • ONE_GB

      public static final long ONE_GB
      The number of bytes in a gigabyte.
      See Also:
    • ONE_GB_BI

      public static final BigInteger ONE_GB_BI
      The number of bytes in a gigabyte.
      Since:
      2.4
    • ONE_TB

      public static final long ONE_TB
      The number of bytes in a terabyte.
      See Also:
    • ONE_TB_BI

      public static final BigInteger ONE_TB_BI
      The number of bytes in a terabyte.
      Since:
      2.4
    • ONE_PB

      public static final long ONE_PB
      The number of bytes in a petabyte.
      See Also:
    • ONE_PB_BI

      public static final BigInteger ONE_PB_BI
      The number of bytes in a petabyte.
      Since:
      2.4
    • ONE_EB

      public static final long ONE_EB
      The number of bytes in an exabyte.
      See Also:
    • ONE_EB_BI

      public static final BigInteger ONE_EB_BI
      The number of bytes in an exabyte.
      Since:
      2.4
    • ONE_ZB

      public static final BigInteger ONE_ZB
      The number of bytes in a zettabyte.
    • ONE_YB

      public static final BigInteger ONE_YB
      The number of bytes in a yottabyte.
    • EMPTY_FILE_ARRAY

      public static final File[] EMPTY_FILE_ARRAY
      An empty array of type File.
  • Constructor Details

    • FileUtils

      public FileUtils()
      Instances should NOT be constructed in standard programming.
  • Method Details

    • byteCountToDisplaySize

      public static String byteCountToDisplaySize(BigInteger size)
      Returns a human-readable version of the file size, where the input represents a specific number of bytes.

      If the size is over 1GB, the size is returned as the number of whole GB, i.e. the size is rounded down to the nearest GB boundary.

      Similarly for the 1MB and 1KB boundaries.

      Parameters:
      size - the number of bytes
      Returns:
      a human-readable display value (includes units - EB, PB, TB, GB, MB, KB or bytes)
      Since:
      2.4
      See Also:
    • byteCountToDisplaySize

      public static String byteCountToDisplaySize(long size)
      Returns a human-readable version of the file size, where the input represents a specific number of bytes.

      If the size is over 1GB, the size is returned as the number of whole GB, i.e. the size is rounded down to the nearest GB boundary.

      Similarly for the 1MB and 1KB boundaries.

      Parameters:
      size - the number of bytes
      Returns:
      a human-readable display value (includes units - EB, PB, TB, GB, MB, KB or bytes)
      See Also:
    • checkDirectory

      private static void checkDirectory(File directory)
      Checks that the given File exists and is a directory.
      Parameters:
      directory - The File to check.
      Throws:
      IllegalArgumentException - if the given File does not exist or is not a directory.
    • checkEqualSizes

      private static void checkEqualSizes(File srcFile, File destFile, long srcLen, long dstLen) throws IOException
      Checks that two file lengths are equal.
      Parameters:
      srcFile - Source file.
      destFile - Destination file.
      srcLen - Source file length.
      dstLen - Destination file length
      Throws:
      IOException - Thrown when the given sizes are not equal.
    • checkFileRequirements

      private static void checkFileRequirements(File source, File destination) throws FileNotFoundException
      Checks requirements for file copy.
      Parameters:
      source - the source file
      destination - the destination
      Throws:
      FileNotFoundException - if the destination does not exist
    • checksum

      public static Checksum checksum(File file, Checksum checksum) throws IOException
      Computes the checksum of a file using the specified checksum object. Multiple files may be checked using one Checksum instance if desired simply by reusing the same checksum object. For example:
         long csum = FileUtils.checksum(file, new CRC32()).getValue();
       
      Parameters:
      file - the file to checksum, must not be null
      checksum - the checksum object to be used, must not be null
      Returns:
      the checksum specified, updated with the content of the file
      Throws:
      NullPointerException - if the file or checksum is null
      IllegalArgumentException - if the file is a directory
      IOException - if an IO error occurs reading the file
      Since:
      1.3
    • checksumCRC32

      public static long checksumCRC32(File file) throws IOException
      Computes the checksum of a file using the CRC32 checksum routine. The value of the checksum is returned.
      Parameters:
      file - the file to checksum, must not be null
      Returns:
      the checksum value
      Throws:
      NullPointerException - if the file or checksum is null
      IllegalArgumentException - if the file is a directory
      IOException - if an IO error occurs reading the file
      Since:
      1.3
    • cleanDirectory

      public static void cleanDirectory(File directory) throws IOException
      Cleans a directory without deleting it.
      Parameters:
      directory - directory to clean
      Throws:
      IOException - in case cleaning is unsuccessful
      IllegalArgumentException - if directory does not exist or is not a directory
      See Also:
    • cleanDirectoryOnExit

      private static void cleanDirectoryOnExit(File directory) throws IOException
      Cleans a directory without deleting it.
      Parameters:
      directory - directory to clean, must not be null
      Throws:
      NullPointerException - if the directory is null
      IOException - in case cleaning is unsuccessful
      See Also:
    • contentEquals

      public static boolean contentEquals(File file1, File file2) throws IOException
      Compares the contents of two files to determine if they are equal or not.

      This method checks to see if the two files are different lengths or if they point to the same file, before resorting to byte-by-byte comparison of the contents.

      Code origin: Avalon

      Parameters:
      file1 - the first file
      file2 - the second file
      Returns:
      true if the content of the files are equal or they both don't exist, false otherwise
      Throws:
      IOException - in case of an I/O error
      See Also:
    • contentEqualsIgnoreEOL

      public static boolean contentEqualsIgnoreEOL(File file1, File file2, String charsetName) throws IOException
      Compares the contents of two files to determine if they are equal or not.

      This method checks to see if the two files point to the same file, before resorting to line-by-line comparison of the contents.

      Parameters:
      file1 - the first file
      file2 - the second file
      charsetName - the name of the requested charset. May be null, in which case the platform default is used
      Returns:
      true if the content of the files are equal or neither exists, false otherwise
      Throws:
      IOException - in case of an I/O error
      Since:
      2.2
      See Also:
    • convertFileCollectionToFileArray

      public static File[] convertFileCollectionToFileArray(Collection<File> files)
      Converts a Collection containing java.io.File instanced into array representation. This is to account for the difference between File.listFiles() and FileUtils.listFiles().
      Parameters:
      files - a Collection containing java.io.File instances
      Returns:
      an array of java.io.File
    • copyDirectory

      public static void copyDirectory(File srcDir, File destDir) throws IOException
      Copies a whole directory to a new location preserving the file dates.

      This method copies the specified directory and all its child directories and files to the specified destination. The destination is the new location and name of the directory.

      The destination directory is created if it does not exist. If the destination directory did exist, then this method merges the source with the destination, with the source taking precedence.

      Note: This method tries to preserve the files' last modified date/times using File.setLastModified(long), however it is not guaranteed that those operations will succeed. If the modification operation fails, no indication is provided.

      Parameters:
      srcDir - an existing directory to copy, must not be null
      destDir - the new directory, must not be null
      Throws:
      NullPointerException - if source or destination is null
      IOException - if source or destination is invalid
      IOException - if an IO error occurs during copying
      Since:
      1.1
    • copyDirectory

      public static void copyDirectory(File srcDir, File destDir, boolean preserveFileDate) throws IOException
      Copies a whole directory to a new location.

      This method copies the contents of the specified source directory to within the specified destination directory.

      The destination directory is created if it does not exist. If the destination directory did exist, then this method merges the source with the destination, with the source taking precedence.

      Note: Setting preserveFileDate to true tries to preserve the files' last modified date/times using File.setLastModified(long), however it is not guaranteed that those operations will succeed. If the modification operation fails, no indication is provided.

      Parameters:
      srcDir - an existing directory to copy, must not be null
      destDir - the new directory, must not be null
      preserveFileDate - true if the file date of the copy should be the same as the original
      Throws:
      NullPointerException - if source or destination is null
      IOException - if source or destination is invalid
      IOException - if an IO error occurs during copying
      Since:
      1.1
    • copyDirectory

      public static void copyDirectory(File srcDir, File destDir, FileFilter filter) throws IOException
      Copies a filtered directory to a new location preserving the file dates.

      This method copies the contents of the specified source directory to within the specified destination directory.

      The destination directory is created if it does not exist. If the destination directory did exist, then this method merges the source with the destination, with the source taking precedence.

      Note: This method tries to preserve the files' last modified date/times using File.setLastModified(long), however it is not guaranteed that those operations will succeed. If the modification operation fails, no indication is provided.

      Example: Copy directories only
        // only copy the directory structure
        FileUtils.copyDirectory(srcDir, destDir, DirectoryFileFilter.DIRECTORY);
        
      Example: Copy directories and txt files
        // Create a filter for ".txt" files
        IOFileFilter txtSuffixFilter = FileFilterUtils.suffixFileFilter(".txt");
        IOFileFilter txtFiles = FileFilterUtils.andFileFilter(FileFileFilter.FILE, txtSuffixFilter);
      
        // Create a filter for either directories or ".txt" files
        FileFilter filter = FileFilterUtils.orFileFilter(DirectoryFileFilter.DIRECTORY, txtFiles);
      
        // Copy using the filter
        FileUtils.copyDirectory(srcDir, destDir, filter);
        
      Parameters:
      srcDir - an existing directory to copy, must not be null
      destDir - the new directory, must not be null
      filter - the filter to apply, null means copy all directories and files should be the same as the original
      Throws:
      NullPointerException - if source or destination is null
      IOException - if source or destination is invalid
      IOException - if an IO error occurs during copying
      Since:
      1.4
    • copyDirectory

      public static void copyDirectory(File srcDir, File destDir, FileFilter filter, boolean preserveFileDate) throws IOException
      Copies a filtered directory to a new location.

      This method copies the contents of the specified source directory to within the specified destination directory.

      The destination directory is created if it does not exist. If the destination directory did exist, then this method merges the source with the destination, with the source taking precedence.

      Note: Setting preserveFileDate to true tries to preserve the files' last modified date/times using File.setLastModified(long), however it is not guaranteed that those operations will succeed. If the modification operation fails, no indication is provided.

      Example: Copy directories only
        // only copy the directory structure
        FileUtils.copyDirectory(srcDir, destDir, DirectoryFileFilter.DIRECTORY, false);
        
      Example: Copy directories and txt files
        // Create a filter for ".txt" files
        IOFileFilter txtSuffixFilter = FileFilterUtils.suffixFileFilter(".txt");
        IOFileFilter txtFiles = FileFilterUtils.andFileFilter(FileFileFilter.FILE, txtSuffixFilter);
      
        // Create a filter for either directories or ".txt" files
        FileFilter filter = FileFilterUtils.orFileFilter(DirectoryFileFilter.DIRECTORY, txtFiles);
      
        // Copy using the filter
        FileUtils.copyDirectory(srcDir, destDir, filter, false);
        
      Parameters:
      srcDir - an existing directory to copy, must not be null
      destDir - the new directory, must not be null
      filter - the filter to apply, null means copy all directories and files
      preserveFileDate - true if the file date of the copy should be the same as the original
      Throws:
      NullPointerException - if source or destination is null
      IOException - if source or destination is invalid
      IOException - if an IO error occurs during copying
      Since:
      1.4
    • copyDirectory

      public static void copyDirectory(File srcDir, File destDir, FileFilter filter, boolean preserveFileDate, CopyOption... copyOptions) throws IOException
      Copies a filtered directory to a new location.

      This method copies the contents of the specified source directory to within the specified destination directory.

      The destination directory is created if it does not exist. If the destination directory did exist, then this method merges the source with the destination, with the source taking precedence.

      Note: Setting preserveFileDate to true tries to preserve the files' last modified date/times using File.setLastModified(long), however it is not guaranteed that those operations will succeed. If the modification operation fails, no indication is provided.

      Example: Copy directories only
        // only copy the directory structure
        FileUtils.copyDirectory(srcDir, destDir, DirectoryFileFilter.DIRECTORY, false);
        
      Example: Copy directories and txt files
        // Create a filter for ".txt" files
        IOFileFilter txtSuffixFilter = FileFilterUtils.suffixFileFilter(".txt");
        IOFileFilter txtFiles = FileFilterUtils.andFileFilter(FileFileFilter.FILE, txtSuffixFilter);
      
        // Create a filter for either directories or ".txt" files
        FileFilter filter = FileFilterUtils.orFileFilter(DirectoryFileFilter.DIRECTORY, txtFiles);
      
        // Copy using the filter
        FileUtils.copyDirectory(srcDir, destDir, filter, false);
        
      Parameters:
      srcDir - an existing directory to copy, must not be null
      destDir - the new directory, must not be null
      filter - the filter to apply, null means copy all directories and files
      preserveFileDate - true if the file date of the copy should be the same as the original
      copyOptions - options specifying how the copy should be done, for example StandardCopyOption.
      Throws:
      NullPointerException - if source or destination is null
      IOException - if source or destination is invalid
      IOException - if an IO error occurs during copying
      Since:
      2.8.0
    • copyDirectoryToDirectory

      public static void copyDirectoryToDirectory(File sourceDir, File destinationDir) throws IOException
      Copies a directory to within another directory preserving the file dates.

      This method copies the source directory and all its contents to a directory of the same name in the specified destination directory.

      The destination directory is created if it does not exist. If the destination directory did exist, then this method merges the source with the destination, with the source taking precedence.

      Note: This method tries to preserve the files' last modified date/times using File.setLastModified(long), however it is not guaranteed that those operations will succeed. If the modification operation fails, no indication is provided.

      Parameters:
      sourceDir - an existing directory to copy, must not be null
      destinationDir - the directory to place the copy in, must not be null
      Throws:
      NullPointerException - if source or destination is null
      IllegalArgumentException - if srcDir or destDir is not a directory
      IOException - if source or destination is invalid
      IOException - if an IO error occurs during copying
      Since:
      1.2
    • copyFile

      public static void copyFile(File srcFile, File destFile) throws IOException
      Copies a file to a new location preserving the file date.

      This method copies the contents of the specified source file to the specified destination file. The directory holding the destination file is created if it does not exist. If the destination file exists, then this method will overwrite it.

      Note: This method tries to preserve the file's last modified date/times using File.setLastModified(long), however it is not guaranteed that the operation will succeed. If the modification operation fails, no indication is provided.

      Parameters:
      srcFile - an existing file to copy, must not be null
      destFile - the new file, must not be null
      Throws:
      NullPointerException - if source or destination is null
      IOException - if source or destination is invalid
      IOException - if an IO error occurs during copying
      IOException - if the output file length is not the same as the input file length after the copy completes
      See Also:
    • copyFile

      public static void copyFile(File srcFile, File destFile, boolean preserveFileDate) throws IOException
      Copies a file to a new location.

      This method copies the contents of the specified source file to the specified destination file. The directory holding the destination file is created if it does not exist. If the destination file exists, then this method will overwrite it.

      Note: Setting preserveFileDate to true tries to preserve the file's last modified date/times using File.setLastModified(long), however it is not guaranteed that the operation will succeed. If the modification operation fails, no indication is provided.

      Parameters:
      srcFile - an existing file to copy, must not be null
      destFile - the new file, must not be null
      preserveFileDate - true if the file date of the copy should be the same as the original
      Throws:
      NullPointerException - if source or destination is null
      IOException - if source or destination is invalid
      IOException - if an IO error occurs during copying
      IOException - if the output file length is not the same as the input file length after the copy completes
      See Also:
    • copyFile

      public static void copyFile(File srcFile, File destFile, boolean preserveFileDate, CopyOption... copyOptions) throws IOException
      Copies a file to a new location.

      This method copies the contents of the specified source file to the specified destination file. The directory holding the destination file is created if it does not exist. If the destination file exists, then this method will overwrite it.

      Note: Setting preserveFileDate to true tries to preserve the file's last modified date/times using File.setLastModified(long), however it is not guaranteed that the operation will succeed. If the modification operation fails, no indication is provided.

      Parameters:
      srcFile - an existing file to copy, must not be null
      destFile - the new file, must not be null
      preserveFileDate - true if the file date of the copy should be the same as the original
      copyOptions - options specifying how the copy should be done, for example StandardCopyOption.
      Throws:
      NullPointerException - if source or destination is null
      IOException - if source or destination is invalid
      IOException - if an IO error occurs during copying
      IOException - if the output file length is not the same as the input file length after the copy completes
      Since:
      2.8.0
      See Also:
    • copyFile

      public static long copyFile(File input, OutputStream output) throws IOException
      Copy bytes from a File to an OutputStream.

      This method buffers the input internally, so there is no need to use a BufferedInputStream.

      Parameters:
      input - the File to read from
      output - the OutputStream to write to
      Returns:
      the number of bytes copied
      Throws:
      NullPointerException - if the input or output is null
      IOException - if an I/O error occurs
      Since:
      2.1
    • copyFileToDirectory

      public static void copyFileToDirectory(File srcFile, File destDir) throws IOException
      Copies a file to a directory preserving the file date.

      This method copies the contents of the specified source file to a file of the same name in the specified destination directory. The destination directory is created if it does not exist. If the destination file exists, then this method will overwrite it.

      Note: This method tries to preserve the file's last modified date/times using File.setLastModified(long), however it is not guaranteed that the operation will succeed. If the modification operation fails, no indication is provided.

      Parameters:
      srcFile - an existing file to copy, must not be null
      destDir - the directory to place the copy in, must not be null
      Throws:
      NullPointerException - if source or destination is null
      IOException - if source or destination is invalid
      IOException - if an IO error occurs during copying
      See Also:
    • copyFileToDirectory

      public static void copyFileToDirectory(File sourceFile, File destinationDir, boolean preserveFileDate) throws IOException
      Copies a file to a directory optionally preserving the file date.

      This method copies the contents of the specified source file to a file of the same name in the specified destination directory. The destination directory is created if it does not exist. If the destination file exists, then this method will overwrite it.

      Note: Setting preserveFileDate to true tries to preserve the file's last modified date/times using File.setLastModified(long), however it is not guaranteed that the operation will succeed. If the modification operation fails, no indication is provided.

      Parameters:
      sourceFile - an existing file to copy, must not be null
      destinationDir - the directory to place the copy in, must not be null
      preserveFileDate - true if the file date of the copy should be the same as the original
      Throws:
      NullPointerException - if source or destination is null
      IOException - if source or destination is invalid
      IOException - if an IO error occurs during copying
      IOException - if the output file length is not the same as the input file length after the copy completes
      Since:
      1.3
      See Also:
    • copyInputStreamToFile

      public static void copyInputStreamToFile(InputStream source, File destination) throws IOException
      Copies bytes from an InputStream source to a file destination. The directories up to destination will be created if they don't already exist. destination will be overwritten if it already exists. The source stream is closed. See copyToFile(InputStream, File) for a method that does not close the input stream.
      Parameters:
      source - the InputStream to copy bytes from, must not be null, will be closed
      destination - the non-directory File to write bytes to (possibly overwriting), must not be null
      Throws:
      IOException - if destination is a directory
      IOException - if destination cannot be written
      IOException - if destination needs creating but can't be
      IOException - if an IO error occurs during copying
      Since:
      2.0
    • copyToDirectory

      public static void copyToDirectory(File sourceFile, File destinationDir) throws IOException
      Copies a file or directory to within another directory preserving the file dates.

      This method copies the source file or directory, along all its contents, to a directory of the same name in the specified destination directory.

      The destination directory is created if it does not exist. If the destination directory did exist, then this method merges the source with the destination, with the source taking precedence.

      Note: This method tries to preserve the files' last modified date/times using File.setLastModified(long), however it is not guaranteed that those operations will succeed. If the modification operation fails, no indication is provided.

      Parameters:
      sourceFile - an existing file or directory to copy, must not be null
      destinationDir - the directory to place the copy in, must not be null
      Throws:
      NullPointerException - if source or destination is null
      IOException - if source or destination is invalid
      IOException - if an IO error occurs during copying
      Since:
      2.6
      See Also:
    • copyToDirectory

      public static void copyToDirectory(Iterable<File> sourceIterable, File destinationDir) throws IOException
      Copies a files to a directory preserving each file's date.

      This method copies the contents of the specified source files to a file of the same name in the specified destination directory. The destination directory is created if it does not exist. If the destination file exists, then this method will overwrite it.

      Note: This method tries to preserve the file's last modified date/times using File.setLastModified(long), however it is not guaranteed that the operation will succeed. If the modification operation fails, no indication is provided.

      Parameters:
      sourceIterable - a existing files to copy, must not be null
      destinationDir - the directory to place the copy in, must not be null
      Throws:
      NullPointerException - if source or destination is null
      IOException - if source or destination is invalid
      IOException - if an IO error occurs during copying
      Since:
      2.6
      See Also:
    • copyToFile

      public static void copyToFile(InputStream source, File destination) throws IOException
      Copies bytes from an InputStream source to a file destination. The directories up to destination will be created if they don't already exist. destination will be overwritten if it already exists. The source stream is left open, e.g. for use with ZipInputStream. See copyInputStreamToFile(InputStream, File) for a method that closes the input stream.
      Parameters:
      source - the InputStream to copy bytes from, must not be null
      destination - the non-directory File to write bytes to (possibly overwriting), must not be null
      Throws:
      IOException - if destination is a directory
      IOException - if destination cannot be written
      IOException - if destination needs creating but can't be
      IOException - if an IO error occurs during copying
      Since:
      2.5
    • copyURLToFile

      public static void copyURLToFile(URL source, File destination) throws IOException
      Copies bytes from the URL source to a file destination. The directories up to destination will be created if they don't already exist. destination will be overwritten if it already exists.

      Warning: this method does not set a connection or read timeout and thus might block forever. Use copyURLToFile(URL, File, int, int) with reasonable timeouts to prevent this.

      Parameters:
      source - the URL to copy bytes from, must not be null
      destination - the non-directory File to write bytes to (possibly overwriting), must not be null
      Throws:
      IOException - if source URL cannot be opened
      IOException - if destination is a directory
      IOException - if destination cannot be written
      IOException - if destination needs creating but can't be
      IOException - if an IO error occurs during copying
    • copyURLToFile

      public static void copyURLToFile(URL source, File destination, int connectionTimeout, int readTimeout) throws IOException
      Copies bytes from the URL source to a file destination. The directories up to destination will be created if they don't already exist. destination will be overwritten if it already exists.
      Parameters:
      source - the URL to copy bytes from, must not be null
      destination - the non-directory File to write bytes to (possibly overwriting), must not be null
      connectionTimeout - the number of milliseconds until this method will timeout if no connection could be established to the source
      readTimeout - the number of milliseconds until this method will timeout if no data could be read from the source
      Throws:
      IOException - if source URL cannot be opened
      IOException - if destination is a directory
      IOException - if destination cannot be written
      IOException - if destination needs creating but can't be
      IOException - if an IO error occurs during copying
      Since:
      2.0
    • decodeUrl

      static String decodeUrl(String url)
      Decodes the specified URL as per RFC 3986, i.e. transforms percent-encoded octets to characters by decoding with the UTF-8 character set. This function is primarily intended for usage with URL which unfortunately does not enforce proper URLs. As such, this method will leniently accept invalid characters or malformed percent-encoded octets and simply pass them literally through to the result string. Except for rare edge cases, this will make unencoded URLs pass through unaltered.
      Parameters:
      url - The URL to decode, may be null.
      Returns:
      The decoded URL or null if the input was null.
    • deleteDirectory

      public static void deleteDirectory(File directory) throws IOException
      Deletes a directory recursively.
      Parameters:
      directory - directory to delete
      Throws:
      IOException - in case deletion is unsuccessful
      IllegalArgumentException - if directory does not exist or is not a directory
    • deleteDirectoryOnExit

      private static void deleteDirectoryOnExit(File directory) throws IOException
      Schedules a directory recursively for deletion on JVM exit.
      Parameters:
      directory - directory to delete, must not be null
      Throws:
      NullPointerException - if the directory is null
      IOException - in case deletion is unsuccessful
    • deleteQuietly

      public static boolean deleteQuietly(File file)
      Deletes a file, never throwing an exception. If file is a directory, delete it and all sub-directories.

      The difference between File.delete() and this method are:

      • A directory to be deleted does not have to be empty.
      • No exceptions are thrown when a file or directory cannot be deleted.
      Parameters:
      file - file or directory to delete, can be null
      Returns:
      true if the file or directory was deleted, otherwise false
      Since:
      1.4
    • directoryContains

      public static boolean directoryContains(File directory, File child) throws IOException
      Determines whether the parent directory contains the child element (a file or directory).

      Files are normalized before comparison.

      Edge cases:
      • A directory must not be null: if null, throw IllegalArgumentException
      • A directory must be a directory: if not a directory, throw IllegalArgumentException
      • A directory does not contain itself: return false
      • A null child file is not contained in any parent: return false
      Parameters:
      directory - the file to consider as the parent.
      child - the file to consider as the child.
      Returns:
      true is the candidate leaf is under by the specified composite. False otherwise.
      Throws:
      IOException - if an IO error occurs while checking the files.
      IllegalArgumentException - if directory is null or not a directory.
      Since:
      2.2
      See Also:
    • doCopyDirectory

      private static void doCopyDirectory(File srcDir, File destDir, FileFilter filter, boolean preserveFileDate, List<String> exclusionList, CopyOption... copyOptions) throws IOException
      Internal copy directory method.
      Parameters:
      srcDir - the validated source directory, must not be null
      destDir - the validated destination directory, must not be null
      filter - the filter to apply, null means copy all directories and files
      preserveFileDate - whether to preserve the file date
      exclusionList - List of files and directories to exclude from the copy, may be null
      copyOptions - options specifying how the copy should be done, for example StandardCopyOption.
      Throws:
      IOException - if an error occurs
    • doCopyFile

      private static void doCopyFile(File srcFile, File destFile, boolean preserveFileDate, CopyOption... copyOptions) throws IOException
      Internal copy file method. This uses the original file length, and throws an IOException if the output file length is different from the current input file length. So it may fail if the file changes size. It may also fail with "IllegalArgumentException: Negative size" if the input file is truncated part way through copying the data and the new file size is less than the current position.
      Parameters:
      srcFile - the validated source file, must not be null
      destFile - the validated destination file, must not be null
      preserveFileDate - whether to preserve the file date
      copyOptions - options specifying how the copy should be done, for example StandardCopyOption.
      Throws:
      IOException - if an error occurs
      IOException - if the output file length is not the same as the input file length after the copy completes
      IllegalArgumentException - "Negative size" if the file is truncated so that the size is less than the position
    • forceDelete

      public static void forceDelete(File file) throws IOException
      Deletes a file. If file is a directory, delete it and all sub-directories.

      The difference between File.delete() and this method are:

      • The directory does not have to be empty.
      • You get exceptions when a file or directory cannot be delete; File.delete() returns a boolean.
      Parameters:
      file - file or directory to delete, must not be null
      Throws:
      NullPointerException - if the directory is null
      FileNotFoundException - if the file was not found
      IOException - in case deletion is unsuccessful
    • forceDeleteOnExit

      public static void forceDeleteOnExit(File file) throws IOException
      Schedules a file to be deleted when JVM exits. If file is directory delete it and all sub-directories.
      Parameters:
      file - file or directory to delete, must not be null
      Throws:
      NullPointerException - if the file is null
      IOException - in case deletion is unsuccessful
    • forceMkdir

      public static void forceMkdir(File directory) throws IOException
      Makes a directory, including any necessary but nonexistent parent directories. If a file already exists with specified name but it is not a directory then an IOException is thrown. If the directory cannot be created (or the file already exists but is not a directory) then an IOException is thrown.
      Parameters:
      directory - directory to create, must not be null
      Throws:
      NullPointerException - if the directory is null
      IOException - if the directory cannot be created or the file already exists but is not a directory
    • forceMkdirParent

      public static void forceMkdirParent(File file) throws IOException
      Makes any necessary but nonexistent parent directories for a given File. If the parent directory cannot be created then an IOException is thrown.
      Parameters:
      file - file with parent to create, must not be null
      Throws:
      NullPointerException - if the file is null
      IOException - if the parent directory cannot be created
      Since:
      2.5
    • getFile

      public static File getFile(File directory, String... names)
      Construct a file from the set of name elements.
      Parameters:
      directory - the parent directory
      names - the name elements
      Returns:
      the file
      Since:
      2.1
    • getFile

      public static File getFile(String... names)
      Construct a file from the set of name elements.
      Parameters:
      names - the name elements
      Returns:
      the file
      Since:
      2.1
    • getTempDirectory

      public static File getTempDirectory()
      Returns a File representing the system temporary directory.
      Returns:
      the system temporary directory.
      Since:
      2.0
    • getTempDirectoryPath

      public static String getTempDirectoryPath()
      Returns the path to the system temporary directory.
      Returns:
      the path to the system temporary directory.
      Since:
      2.0
    • getUserDirectory

      public static File getUserDirectory()
      Returns a File representing the user's home directory.
      Returns:
      the user's home directory.
      Since:
      2.0
    • getUserDirectoryPath

      public static String getUserDirectoryPath()
      Returns the path to the user's home directory.
      Returns:
      the path to the user's home directory.
      Since:
      2.0
    • innerListFiles

      private static void innerListFiles(Collection<File> files, File directory, IOFileFilter filter, boolean includeSubDirectories)
      Finds files within a given directory (and optionally its subdirectories). All files found are filtered by an IOFileFilter.
      Parameters:
      files - the collection of files found.
      directory - the directory to search in.
      filter - the filter to apply to files and directories.
      includeSubDirectories - indicates if will include the subdirectories themselves
    • innerListFilesOrDirectories

      private static Collection<File> innerListFilesOrDirectories(File directory, IOFileFilter fileFilter, IOFileFilter dirFilter, boolean includeSubDirectories)
      Finds files within a given directory (and optionally its subdirectories). All files found are filtered by an IOFileFilter.
      Parameters:
      directory - the directory to search in
      fileFilter - filter to apply when finding files.
      dirFilter - optional filter to apply when finding subdirectories. If this parameter is null, subdirectories will not be included in the search. Use TrueFileFilter.INSTANCE to match all directories.
      includeSubDirectories - indicates if will include the subdirectories themselves
      Returns:
      a collection of java.io.File with the matching files
      See Also:
    • isFileNewer

      public static boolean isFileNewer(File file, ChronoLocalDate chronoLocalDate)
      Tests if the specified File is newer than the specified ChronoLocalDate at the current time.
      Parameters:
      file - the File of which the modification date must be compared
      chronoLocalDate - the date reference
      Returns:
      true if the File exists and has been modified after the given ChronoLocalDate at the current time.
      Throws:
      NullPointerException - if the file or local date is null
      Since:
      2.8.0
    • isFileNewer

      public static boolean isFileNewer(File file, ChronoLocalDate chronoLocalDate, LocalTime localTime)
      Tests if the specified File is newer than the specified ChronoLocalDate at the specified time.
      Parameters:
      file - the File of which the modification date must be compared
      chronoLocalDate - the date reference
      localTime - the time reference
      Returns:
      true if the File exists and has been modified after the given ChronoLocalDate at the given time.
      Throws:
      NullPointerException - if the file, local date or zone ID is null
      Since:
      2.8.0
    • isFileNewer

      public static boolean isFileNewer(File file, ChronoLocalDateTime<?> chronoLocalDateTime)
      Tests if the specified File is newer than the specified ChronoLocalDateTime at the system-default time zone.
      Parameters:
      file - the File of which the modification date must be compared
      chronoLocalDateTime - the date reference
      Returns:
      true if the File exists and has been modified after the given ChronoLocalDateTime at the system-default time zone.
      Throws:
      NullPointerException - if the file or local date time is null
      Since:
      2.8.0
    • isFileNewer

      public static boolean isFileNewer(File file, ChronoLocalDateTime<?> chronoLocalDateTime, ZoneId zoneId)
      Tests if the specified File is newer than the specified ChronoLocalDateTime at the specified ZoneId.
      Parameters:
      file - the File of which the modification date must be compared
      chronoLocalDateTime - the date reference
      zoneId - the time zone
      Returns:
      true if the File exists and has been modified after the given ChronoLocalDateTime at the given ZoneId.
      Throws:
      NullPointerException - if the file, local date time or zone ID is null
      Since:
      2.8.0
    • isFileNewer

      public static boolean isFileNewer(File file, ChronoZonedDateTime<?> chronoZonedDateTime)
      Tests if the specified File is newer than the specified ChronoZonedDateTime.
      Parameters:
      file - the File of which the modification date must be compared
      chronoZonedDateTime - the date reference
      Returns:
      true if the File exists and has been modified after the given ChronoZonedDateTime.
      Throws:
      NullPointerException - if the file or zoned date time is null
      Since:
      2.8.0
    • isFileNewer

      public static boolean isFileNewer(File file, Date date)
      Tests if the specified File is newer than the specified Date.
      Parameters:
      file - the File of which the modification date must be compared
      date - the date reference
      Returns:
      true if the File exists and has been modified after the given Date.
      Throws:
      NullPointerException - if the file or date is null
    • isFileNewer

      public static boolean isFileNewer(File file, File reference)
      Tests if the specified File is newer than the reference File.
      Parameters:
      file - the File of which the modification date must be compared
      reference - the File of which the modification date is used
      Returns:
      true if the File exists and has been modified more recently than the reference File
      Throws:
      NullPointerException - if the file or reference file is null
      IllegalArgumentException - if the reference file doesn't exist
    • isFileNewer

      public static boolean isFileNewer(File file, Instant instant)
      Tests if the specified File is newer than the specified Instant.
      Parameters:
      file - the File of which the modification date must be compared
      instant - the date reference
      Returns:
      true if the File exists and has been modified after the given Instant.
      Throws:
      NullPointerException - if the file or instant is null
      Since:
      2.8.0
    • isFileNewer

      public static boolean isFileNewer(File file, long timeMillis)
      Tests if the specified File is newer than the specified time reference.
      Parameters:
      file - the File of which the modification date must be compared
      timeMillis - the time reference measured in milliseconds since the epoch (00:00:00 GMT, January 1, 1970)
      Returns:
      true if the File exists and has been modified after the given time reference.
      Throws:
      NullPointerException - if the file is null
    • isFileOlder

      public static boolean isFileOlder(File file, ChronoLocalDate chronoLocalDate)
      Tests if the specified File is older than the specified ChronoLocalDate at the current time.
      Parameters:
      file - the File of which the modification date must be compared
      chronoLocalDate - the date reference
      Returns:
      true if the File exists and has been modified before the given ChronoLocalDate at the current time.
      Throws:
      NullPointerException - if the file or local date is null
      Since:
      2.8.0
    • isFileOlder

      public static boolean isFileOlder(File file, ChronoLocalDate chronoLocalDate, LocalTime localTime)
      Tests if the specified File is older than the specified ChronoLocalDate at the specified LocalTime.
      Parameters:
      file - the File of which the modification date must be compared
      chronoLocalDate - the date reference
      localTime - the time reference
      Returns:
      true if the File exists and has been modified before the given ChronoLocalDate at the specified time.
      Throws:
      NullPointerException - if the file, local date or local time is null
      Since:
      2.8.0
    • isFileOlder

      public static boolean isFileOlder(File file, ChronoLocalDateTime<?> chronoLocalDateTime)
      Tests if the specified File is older than the specified ChronoLocalDateTime at the system-default time zone.
      Parameters:
      file - the File of which the modification date must be compared
      chronoLocalDateTime - the date reference
      Returns:
      true if the File exists and has been modified before the given ChronoLocalDateTime at the system-default time zone.
      Throws:
      NullPointerException - if the file or local date time is null
      Since:
      2.8.0
    • isFileOlder

      public static boolean isFileOlder(File file, ChronoLocalDateTime<?> chronoLocalDateTime, ZoneId zoneId)
      Tests if the specified File is older than the specified ChronoLocalDateTime at the specified ZoneId.
      Parameters:
      file - the File of which the modification date must be compared
      chronoLocalDateTime - the date reference
      zoneId - the time zone
      Returns:
      true if the File exists and has been modified before the given ChronoLocalDateTime at the given ZoneId.
      Throws:
      NullPointerException - if the file, local date time or zone ID is null
      Since:
      2.8.0
    • isFileOlder

      public static boolean isFileOlder(File file, ChronoZonedDateTime<?> chronoZonedDateTime)
      Tests if the specified File is older than the specified ChronoZonedDateTime.
      Parameters:
      file - the File of which the modification date must be compared
      chronoZonedDateTime - the date reference
      Returns:
      true if the File exists and has been modified before the given ChronoZonedDateTime.
      Throws:
      NullPointerException - if the file or zoned date time is null
      Since:
      2.8.0
    • isFileOlder

      public static boolean isFileOlder(File file, Date date)
      Tests if the specified File is older than the specified Date.
      Parameters:
      file - the File of which the modification date must be compared
      date - the date reference
      Returns:
      true if the File exists and has been modified before the given Date.
      Throws:
      NullPointerException - if the file or date is null
    • isFileOlder

      public static boolean isFileOlder(File file, File reference)
      Tests if the specified File is older than the reference File.
      Parameters:
      file - the File of which the modification date must be compared
      reference - the File of which the modification date is used
      Returns:
      true if the File exists and has been modified before the reference File
      Throws:
      NullPointerException - if the file or reference file is null
      IllegalArgumentException - if the reference file doesn't exist
    • isFileOlder

      public static boolean isFileOlder(File file, Instant instant)
      Tests if the specified File is older than the specified Instant.
      Parameters:
      file - the File of which the modification date must be compared
      instant - the date reference
      Returns:
      true if the File exists and has been modified before the given Instant.
      Throws:
      NullPointerException - if the file or instant is null
      Since:
      2.8.0
    • isFileOlder

      public static boolean isFileOlder(File file, long timeMillis)
      Tests if the specified File is older than the specified time reference.
      Parameters:
      file - the File of which the modification date must be compared
      timeMillis - the time reference measured in milliseconds since the epoch (00:00:00 GMT, January 1, 1970)
      Returns:
      true if the File exists and has been modified before the given time reference.
      Throws:
      NullPointerException - if the file is null
    • isSymlink

      public static boolean isSymlink(File file)
      Determines whether the specified file is a Symbolic Link rather than an actual file.

      Will not return true if there is a Symbolic Link anywhere in the path, only if the specific file is.

      When using jdk1.7, this method delegates to boolean java.nio.file.Files.isSymbolicLink(Path path)

      Note: the current implementation always returns false if running on jkd1.6 and the system is detected as Windows using FilenameUtils.isSystemWindows()

      For code that runs on Java 1.7 or later, use the following method instead:

      boolean java.nio.file.Files.isSymbolicLink(Path path)
      Parameters:
      file - the file to check
      Returns:
      true if the file is a Symbolic Link
      Since:
      2.0
    • iterateFiles

      public static Iterator<File> iterateFiles(File directory, IOFileFilter fileFilter, IOFileFilter dirFilter)
      Allows iteration over the files in given directory (and optionally its subdirectories).

      All files found are filtered by an IOFileFilter. This method is based on listFiles(File, IOFileFilter, IOFileFilter), which supports Iterable ('foreach' loop).

      Parameters:
      directory - the directory to search in
      fileFilter - filter to apply when finding files.
      dirFilter - optional filter to apply when finding subdirectories. If this parameter is null, subdirectories will not be included in the search. Use TrueFileFilter.INSTANCE to match all directories.
      Returns:
      an iterator of java.io.File for the matching files
      Since:
      1.2
      See Also:
    • iterateFiles

      public static Iterator<File> iterateFiles(File directory, String[] extensions, boolean recursive)
      Allows iteration over the files in a given directory (and optionally its subdirectories) which match an array of extensions. This method is based on listFiles(File, String[], boolean), which supports Iterable ('foreach' loop).
      Parameters:
      directory - the directory to search in
      extensions - an array of extensions, ex. {"java","xml"}. If this parameter is null, all files are returned.
      recursive - if true all subdirectories are searched as well
      Returns:
      an iterator of java.io.File with the matching files
      Since:
      1.2
    • iterateFilesAndDirs

      public static Iterator<File> iterateFilesAndDirs(File directory, IOFileFilter fileFilter, IOFileFilter dirFilter)
      Allows iteration over the files in given directory (and optionally its subdirectories).

      All files found are filtered by an IOFileFilter. This method is based on listFilesAndDirs(File, IOFileFilter, IOFileFilter), which supports Iterable ('foreach' loop).

      The resulting iterator includes the subdirectories themselves.

      Parameters:
      directory - the directory to search in
      fileFilter - filter to apply when finding files.
      dirFilter - optional filter to apply when finding subdirectories. If this parameter is null, subdirectories will not be included in the search. Use TrueFileFilter.INSTANCE to match all directories.
      Returns:
      an iterator of java.io.File for the matching files
      Since:
      2.2
      See Also:
    • lineIterator

      public static LineIterator lineIterator(File file) throws IOException
      Returns an Iterator for the lines in a File using the default encoding for the VM.
      Parameters:
      file - the file to open for input, must not be null
      Returns:
      an Iterator of the lines in the file, never null
      Throws:
      IOException - in case of an I/O error (file closed)
      Since:
      1.3
      See Also:
    • lineIterator

      public static LineIterator lineIterator(File file, String charsetName) throws IOException
      Returns an Iterator for the lines in a File.

      This method opens an InputStream for the file. When you have finished with the iterator you should close the stream to free internal resources. This can be done by calling the LineIterator.close() or LineIterator.closeQuietly(LineIterator) method.

      The recommended usage pattern is:

       LineIterator it = FileUtils.lineIterator(file, "UTF-8");
       try {
         while (it.hasNext()) {
           String line = it.nextLine();
           /// do something with line
         }
       } finally {
         LineIterator.closeQuietly(iterator);
       }
       

      If an exception occurs during the creation of the iterator, the underlying stream is closed.

      Parameters:
      file - the file to open for input, must not be null
      charsetName - the name of the requested charset, null means platform default
      Returns:
      an Iterator of the lines in the file, never null
      Throws:
      IOException - in case of an I/O error (file closed)
      Since:
      1.2
    • listFiles

      public static Collection<File> listFiles(File directory, IOFileFilter fileFilter, IOFileFilter dirFilter)
      Finds files within a given directory (and optionally its subdirectories). All files found are filtered by an IOFileFilter.

      If your search should recurse into subdirectories you can pass in an IOFileFilter for directories. You don't need to bind a DirectoryFileFilter (via logical AND) to this filter. This method does that for you.

      An example: If you want to search through all directories called "temp" you pass in FileFilterUtils.NameFileFilter("temp")

      Another common usage of this method is find files in a directory tree but ignoring the directories generated CVS. You can simply pass in FileFilterUtils.makeCVSAware(null).

      Parameters:
      directory - the directory to search in
      fileFilter - filter to apply when finding files. Must not be null, use TrueFileFilter.INSTANCE to match all files in selected directories.
      dirFilter - optional filter to apply when finding subdirectories. If this parameter is null, subdirectories will not be included in the search. Use TrueFileFilter.INSTANCE to match all directories.
      Returns:
      a collection of java.io.File with the matching files
      See Also:
    • listFiles

      public static Collection<File> listFiles(File directory, String[] extensions, boolean recursive)
      Finds files within a given directory (and optionally its subdirectories) which match an array of extensions.
      Parameters:
      directory - the directory to search in
      extensions - an array of extensions, ex. {"java","xml"}. If this parameter is null, all files are returned.
      recursive - if true all subdirectories are searched as well
      Returns:
      a collection of java.io.File with the matching files
    • listFilesAndDirs

      public static Collection<File> listFilesAndDirs(File directory, IOFileFilter fileFilter, IOFileFilter dirFilter)
      Finds files within a given directory (and optionally its subdirectories). All files found are filtered by an IOFileFilter.

      The resulting collection includes the starting directory and any subdirectories that match the directory filter.

      Parameters:
      directory - the directory to search in
      fileFilter - filter to apply when finding files.
      dirFilter - optional filter to apply when finding subdirectories. If this parameter is null, subdirectories will not be included in the search. Use TrueFileFilter.INSTANCE to match all directories.
      Returns:
      a collection of java.io.File with the matching files
      Since:
      2.2
      See Also:
    • moveDirectory

      public static void moveDirectory(File srcDir, File destDir) throws IOException
      Moves a directory.

      When the destination directory is on another file system, do a "copy and delete".

      Parameters:
      srcDir - the directory to be moved
      destDir - the destination directory
      Throws:
      NullPointerException - if source or destination is null
      FileExistsException - if the destination directory exists
      IOException - if source or destination is invalid
      IOException - if an IO error occurs moving the file
      Since:
      1.4
    • moveDirectoryToDirectory

      public static void moveDirectoryToDirectory(File src, File destDir, boolean createDestDir) throws IOException
      Moves a directory to another directory.
      Parameters:
      src - the file to be moved
      destDir - the destination file
      createDestDir - If true create the destination directory, otherwise if false throw an IOException
      Throws:
      NullPointerException - if source or destination is null
      FileExistsException - if the directory exists in the destination directory
      IOException - if source or destination is invalid
      IOException - if an IO error occurs moving the file
      Since:
      1.4
    • moveFile

      public static void moveFile(File srcFile, File destFile) throws IOException
      Moves a file.

      When the destination file is on another file system, do a "copy and delete".

      Parameters:
      srcFile - the file to be moved
      destFile - the destination file
      Throws:
      NullPointerException - if source or destination is null
      FileExistsException - if the destination file exists
      IOException - if source or destination is invalid
      IOException - if an IO error occurs moving the file
      Since:
      1.4
    • moveFileToDirectory

      public static void moveFileToDirectory(File srcFile, File destDir, boolean createDestDir) throws IOException
      Moves a file to a directory.
      Parameters:
      srcFile - the file to be moved
      destDir - the destination file
      createDestDir - If true create the destination directory, otherwise if false throw an IOException
      Throws:
      NullPointerException - if source or destination is null
      FileExistsException - if the destination file exists
      IOException - if source or destination is invalid
      IOException - if an IO error occurs moving the file
      Since:
      1.4
    • moveToDirectory

      public static void moveToDirectory(File src, File destDir, boolean createDestDir) throws IOException
      Moves a file or directory to the destination directory.

      When the destination is on another file system, do a "copy and delete".

      Parameters:
      src - the file or directory to be moved
      destDir - the destination directory
      createDestDir - If true create the destination directory, otherwise if false throw an IOException
      Throws:
      NullPointerException - if source or destination is null
      FileExistsException - if the directory or file exists in the destination directory
      IOException - if source or destination is invalid
      IOException - if an IO error occurs moving the file
      Since:
      1.4
    • openInputStream

      public static FileInputStream openInputStream(File file) throws IOException
      Opens a FileInputStream for the specified file, providing better error messages than simply calling new FileInputStream(file).

      At the end of the method either the stream will be successfully opened, or an exception will have been thrown.

      An exception is thrown if the file does not exist. An exception is thrown if the file object exists but is a directory. An exception is thrown if the file exists but cannot be read.

      Parameters:
      file - the file to open for input, must not be null
      Returns:
      a new FileInputStream for the specified file
      Throws:
      FileNotFoundException - if the file does not exist
      IOException - if the file object is a directory
      IOException - if the file cannot be read
      Since:
      1.3
    • openOutputStream

      public static FileOutputStream openOutputStream(File file) throws IOException
      Opens a FileOutputStream for the specified file, checking and creating the parent directory if it does not exist.

      At the end of the method either the stream will be successfully opened, or an exception will have been thrown.

      The parent directory will be created if it does not exist. The file will be created if it does not exist. An exception is thrown if the file object exists but is a directory. An exception is thrown if the file exists but cannot be written to. An exception is thrown if the parent directory cannot be created.

      Parameters:
      file - the file to open for output, must not be null
      Returns:
      a new FileOutputStream for the specified file
      Throws:
      IOException - if the file object is a directory
      IOException - if the file cannot be written to
      IOException - if a parent directory needs creating but that fails
      Since:
      1.3
    • openOutputStream

      public static FileOutputStream openOutputStream(File file, boolean append) throws IOException
      Opens a FileOutputStream for the specified file, checking and creating the parent directory if it does not exist.

      At the end of the method either the stream will be successfully opened, or an exception will have been thrown.

      The parent directory will be created if it does not exist. The file will be created if it does not exist. An exception is thrown if the file object exists but is a directory. An exception is thrown if the file exists but cannot be written to. An exception is thrown if the parent directory cannot be created.

      Parameters:
      file - the file to open for output, must not be null
      append - if true, then bytes will be added to the end of the file rather than overwriting
      Returns:
      a new FileOutputStream for the specified file
      Throws:
      IOException - if the file object is a directory
      IOException - if the file cannot be written to
      IOException - if a parent directory needs creating but that fails
      Since:
      2.1
    • readFileToByteArray

      public static byte[] readFileToByteArray(File file) throws IOException
      Reads the contents of a file into a byte array. The file is always closed.
      Parameters:
      file - the file to read, must not be null
      Returns:
      the file contents, never null
      Throws:
      IOException - in case of an I/O error
      Since:
      1.1
    • readFileToString

      @Deprecated public static String readFileToString(File file) throws IOException
      Deprecated.
      2.5 use readFileToString(File, Charset) instead (and specify the appropriate encoding)
      Reads the contents of a file into a String using the default encoding for the VM. The file is always closed.
      Parameters:
      file - the file to read, must not be null
      Returns:
      the file contents, never null
      Throws:
      IOException - in case of an I/O error
      Since:
      1.3.1
    • readFileToString

      public static String readFileToString(File file, Charset charsetName) throws IOException
      Reads the contents of a file into a String. The file is always closed.
      Parameters:
      file - the file to read, must not be null
      charsetName - the name of the requested charset, null means platform default
      Returns:
      the file contents, never null
      Throws:
      IOException - in case of an I/O error
      Since:
      2.3
    • readFileToString

      public static String readFileToString(File file, String charsetName) throws IOException
      Reads the contents of a file into a String. The file is always closed.
      Parameters:
      file - the file to read, must not be null
      charsetName - the name of the requested charset, null means platform default
      Returns:
      the file contents, never null
      Throws:
      IOException - in case of an I/O error
      UnsupportedCharsetException - thrown instead of .UnsupportedEncodingException in version 2.2 if the encoding is not supported.
      Since:
      2.3
    • readLines

      @Deprecated public static List<String> readLines(File file) throws IOException
      Deprecated.
      2.5 use readLines(File, Charset) instead (and specify the appropriate encoding)
      Reads the contents of a file line by line to a List of Strings using the default encoding for the VM. The file is always closed.
      Parameters:
      file - the file to read, must not be null
      Returns:
      the list of Strings representing each line in the file, never null
      Throws:
      IOException - in case of an I/O error
      Since:
      1.3
    • readLines

      public static List<String> readLines(File file, Charset charset) throws IOException
      Reads the contents of a file line by line to a List of Strings. The file is always closed.
      Parameters:
      file - the file to read, must not be null
      charset - the charset to use, null means platform default
      Returns:
      the list of Strings representing each line in the file, never null
      Throws:
      IOException - in case of an I/O error
      Since:
      2.3
    • readLines

      public static List<String> readLines(File file, String charsetName) throws IOException
      Reads the contents of a file line by line to a List of Strings. The file is always closed.
      Parameters:
      file - the file to read, must not be null
      charsetName - the name of the requested charset, null means platform default
      Returns:
      the list of Strings representing each line in the file, never null
      Throws:
      IOException - in case of an I/O error
      UnsupportedCharsetException - thrown instead of .UnsupportedEncodingException in version 2.2 if the encoding is not supported.
      Since:
      1.1
    • setLastModified

      private static void setLastModified(File sourceFile, File targetFile) throws IOException
      Sets the given targetFile's last modified date to the value from sourceFile.
      Parameters:
      sourceFile - The source file to query.
      targetFile - The target file to set.
      Throws:
      IOException - if an error occurs
    • setUpEffectiveDirFilter

      private static IOFileFilter setUpEffectiveDirFilter(IOFileFilter dirFilter)
      Returns a filter that accepts directories in addition to the File objects accepted by the given filter.
      Parameters:
      dirFilter - a base filter to add to
      Returns:
      a filter that accepts directories
    • setUpEffectiveFileFilter

      private static IOFileFilter setUpEffectiveFileFilter(IOFileFilter fileFilter)
      Returns a filter that accepts files in addition to the File objects accepted by the given filter.
      Parameters:
      fileFilter - a base filter to add to
      Returns:
      a filter that accepts files
    • sizeOf

      public static long sizeOf(File file)
      Returns the size of the specified file or directory. If the provided File is a regular file, then the file's length is returned. If the argument is a directory, then the size of the directory is calculated recursively. If a directory or subdirectory is security restricted, its size will not be included.

      Note that overflow is not detected, and the return value may be negative if overflow occurs. See sizeOfAsBigInteger(File) for an alternative method that does not overflow.

      Parameters:
      file - the regular file or directory to return the size of (must not be null).
      Returns:
      the length of the file, or recursive size of the directory, provided (in bytes).
      Throws:
      NullPointerException - if the file is null
      IllegalArgumentException - if the file does not exist.
      Since:
      2.0
    • sizeOf0

      private static long sizeOf0(File file)
      the size of a file
      Parameters:
      file - the file to check
      Returns:
      the size of the file
    • sizeOfAsBigInteger

      public static BigInteger sizeOfAsBigInteger(File file)
      Returns the size of the specified file or directory. If the provided File is a regular file, then the file's length is returned. If the argument is a directory, then the size of the directory is calculated recursively. If a directory or subdirectory is security restricted, its size will not be included.
      Parameters:
      file - the regular file or directory to return the size of (must not be null).
      Returns:
      the length of the file, or recursive size of the directory, provided (in bytes).
      Throws:
      NullPointerException - if the file is null
      IllegalArgumentException - if the file does not exist.
      Since:
      2.4
    • sizeOfBig0

      private static BigInteger sizeOfBig0(File fileOrDir)
      Returns the size of a file
      Parameters:
      fileOrDir - The file
      Returns:
      the size
    • sizeOfDirectory

      public static long sizeOfDirectory(File directory)
      Counts the size of a directory recursively (sum of the length of all files).

      Note that overflow is not detected, and the return value may be negative if overflow occurs. See sizeOfDirectoryAsBigInteger(File) for an alternative method that does not overflow.

      Parameters:
      directory - directory to inspect, must not be null
      Returns:
      size of directory in bytes, 0 if directory is security restricted, a negative number when the real total is greater than Long.MAX_VALUE.
      Throws:
      NullPointerException - if the directory is null
    • sizeOfDirectory0

      private static long sizeOfDirectory0(File directory)
      the size of a director
      Parameters:
      directory - the directory to check
      Returns:
      the size
    • sizeOfDirectoryAsBigInteger

      public static BigInteger sizeOfDirectoryAsBigInteger(File directory)
      Counts the size of a directory recursively (sum of the length of all files).
      Parameters:
      directory - directory to inspect, must not be null
      Returns:
      size of directory in bytes, 0 if directory is security restricted.
      Throws:
      NullPointerException - if the directory is null
      Since:
      2.4
    • sizeOfDirectoryBig0

      private static BigInteger sizeOfDirectoryBig0(File directory)
      Finds the size of a directory
      Parameters:
      directory - The directory
      Returns:
      the size
    • toFile

      public static File toFile(URL url)
      Convert from a URL to a File.

      From version 1.1 this method will decode the URL. Syntax such as file:///my%20docs/file.txt will be correctly decoded to /my docs/file.txt. Starting with version 1.5, this method uses UTF-8 to decode percent-encoded octets to characters. Additionally, malformed percent-encoded octets are handled leniently by passing them through literally.

      Parameters:
      url - the file URL to convert, null returns null
      Returns:
      the equivalent File object, or null if the URL's protocol is not file
    • toFiles

      public static File[] toFiles(URL... urls)
      Converts each of an array of URL to a File.

      Returns an array of the same size as the input. If the input is null, an empty array is returned. If the input contains null, the output array contains null at the same index.

      This method will decode the URL. Syntax such as file:///my%20docs/file.txt will be correctly decoded to /my docs/file.txt.

      Parameters:
      urls - the file URLs to convert, null returns empty array
      Returns:
      a non-null array of Files matching the input, with a null item if there was a null at that index in the input array
      Throws:
      IllegalArgumentException - if any file is not a URL file
      IllegalArgumentException - if any file is incorrectly encoded
      Since:
      1.1
    • toSuffixes

      private static String[] toSuffixes(String... extensions)
      Converts an array of file extensions to suffixes for use with IOFileFilters.
      Parameters:
      extensions - an array of extensions. Format: {"java", "xml"}
      Returns:
      an array of suffixes. Format: {".java", ".xml"}
    • touch

      public static void touch(File file) throws IOException
      Implements the same behavior as the "touch" utility on Unix. It creates a new file with size 0 or, if the file exists already, it is opened and closed without modifying it, but updating the file date and time.

      NOTE: As from v1.3, this method throws an IOException if the last modified date of the file cannot be set. Also, as from v1.3 this method creates parent directories if they do not exist.

      Parameters:
      file - the File to touch
      Throws:
      IOException - If an I/O problem occurs
    • toURLs

      public static URL[] toURLs(File... files) throws IOException
      Converts each of an array of File to a URL.

      Returns an array of the same size as the input.

      Parameters:
      files - the files to convert, must not be null
      Returns:
      an array of URLs matching the input
      Throws:
      IOException - if a file cannot be converted
      NullPointerException - if the parameter is null
    • validateListFilesParameters

      private static void validateListFilesParameters(File directory, IOFileFilter fileFilter)
      Validates the given arguments.
      Parameters:
      directory - The File to test
      fileFilter - The IOFileFilter to test
    • validateMoveParameters

      private static void validateMoveParameters(File source, File destination) throws FileNotFoundException
      Validates the given arguments.
      Parameters:
      source - the file or directory to be moved
      destination - the destination file or directory
      Throws:
      FileNotFoundException - if src file does not exist
    • verifiedListFiles

      private static File[] verifiedListFiles(File directory) throws IOException
      Lists files in a directory, asserting that the supplied directory satisfies exists and is a directory.
      Parameters:
      directory - The directory to list
      Returns:
      The files in the directory, never null.
      Throws:
      IOException - if an I/O error occurs
    • waitFor

      public static boolean waitFor(File file, int seconds)
      Waits for NFS to propagate a file creation, imposing a timeout.

      This method repeatedly tests File.exists() until it returns true up to the maximum time specified in seconds.

      Parameters:
      file - the file to check, must not be null
      seconds - the maximum time in seconds to wait
      Returns:
      true if file exists
      Throws:
      NullPointerException - if the file is null
    • write

      @Deprecated public static void write(File file, CharSequence data) throws IOException
      Deprecated.
      2.5 use write(File, CharSequence, Charset) instead (and specify the appropriate encoding)
      Writes a CharSequence to a file creating the file if it does not exist using the default encoding for the VM.
      Parameters:
      file - the file to write
      data - the content to write to the file
      Throws:
      IOException - in case of an I/O error
      Since:
      2.0
    • write

      @Deprecated public static void write(File file, CharSequence data, boolean append) throws IOException
      Deprecated.
      2.5 use write(File, CharSequence, Charset, boolean) instead (and specify the appropriate encoding)
      Writes a CharSequence to a file creating the file if it does not exist using the default encoding for the VM.
      Parameters:
      file - the file to write
      data - the content to write to the file
      append - if true, then the data will be added to the end of the file rather than overwriting
      Throws:
      IOException - in case of an I/O error
      Since:
      2.1
    • write

      public static void write(File file, CharSequence data, Charset charset) throws IOException
      Writes a CharSequence to a file creating the file if it does not exist.
      Parameters:
      file - the file to write
      data - the content to write to the file
      charset - the name of the requested charset, null means platform default
      Throws:
      IOException - in case of an I/O error
      Since:
      2.3
    • write

      public static void write(File file, CharSequence data, Charset charset, boolean append) throws IOException
      Writes a CharSequence to a file creating the file if it does not exist.
      Parameters:
      file - the file to write
      data - the content to write to the file
      charset - the charset to use, null means platform default
      append - if true, then the data will be added to the end of the file rather than overwriting
      Throws:
      IOException - in case of an I/O error
      Since:
      2.3
    • write

      public static void write(File file, CharSequence data, String charsetName) throws IOException
      Writes a CharSequence to a file creating the file if it does not exist.
      Parameters:
      file - the file to write
      data - the content to write to the file
      charsetName - the name of the requested charset, null means platform default
      Throws:
      IOException - in case of an I/O error
      UnsupportedEncodingException - if the encoding is not supported by the VM
      Since:
      2.0
    • write

      public static void write(File file, CharSequence data, String charsetName, boolean append) throws IOException
      Writes a CharSequence to a file creating the file if it does not exist.
      Parameters:
      file - the file to write
      data - the content to write to the file
      charsetName - the name of the requested charset, null means platform default
      append - if true, then the data will be added to the end of the file rather than overwriting
      Throws:
      IOException - in case of an I/O error
      UnsupportedCharsetException - thrown instead of .UnsupportedEncodingException in version 2.2 if the encoding is not supported by the VM
      Since:
      2.1
    • writeByteArrayToFile

      public static void writeByteArrayToFile(File file, byte[] data) throws IOException
      Writes a byte array to a file creating the file if it does not exist.

      NOTE: As from v1.3, the parent directories of the file will be created if they do not exist.

      Parameters:
      file - the file to write to
      data - the content to write to the file
      Throws:
      IOException - in case of an I/O error
      Since:
      1.1
    • writeByteArrayToFile

      public static void writeByteArrayToFile(File file, byte[] data, boolean append) throws IOException
      Writes a byte array to a file creating the file if it does not exist.
      Parameters:
      file - the file to write to
      data - the content to write to the file
      append - if true, then bytes will be added to the end of the file rather than overwriting
      Throws:
      IOException - in case of an I/O error
      Since:
      2.1
    • writeByteArrayToFile

      public static void writeByteArrayToFile(File file, byte[] data, int off, int len) throws IOException
      Writes len bytes from the specified byte array starting at offset off to a file, creating the file if it does not exist.
      Parameters:
      file - the file to write to
      data - the content to write to the file
      off - the start offset in the data
      len - the number of bytes to write
      Throws:
      IOException - in case of an I/O error
      Since:
      2.5
    • writeByteArrayToFile

      public static void writeByteArrayToFile(File file, byte[] data, int off, int len, boolean append) throws IOException
      Writes len bytes from the specified byte array starting at offset off to a file, creating the file if it does not exist.
      Parameters:
      file - the file to write to
      data - the content to write to the file
      off - the start offset in the data
      len - the number of bytes to write
      append - if true, then bytes will be added to the end of the file rather than overwriting
      Throws:
      IOException - in case of an I/O error
      Since:
      2.5
    • writeLines

      public static void writeLines(File file, Collection<?> lines) throws IOException
      Writes the toString() value of each item in a collection to the specified File line by line. The default VM encoding and the default line ending will be used.
      Parameters:
      file - the file to write to
      lines - the lines to write, null entries produce blank lines
      Throws:
      IOException - in case of an I/O error
      Since:
      1.3
    • writeLines

      public static void writeLines(File file, Collection<?> lines, boolean append) throws IOException
      Writes the toString() value of each item in a collection to the specified File line by line. The default VM encoding and the default line ending will be used.
      Parameters:
      file - the file to write to
      lines - the lines to write, null entries produce blank lines
      append - if true, then the lines will be added to the end of the file rather than overwriting
      Throws:
      IOException - in case of an I/O error
      Since:
      2.1
    • writeLines

      public static void writeLines(File file, Collection<?> lines, String lineEnding) throws IOException
      Writes the toString() value of each item in a collection to the specified File line by line. The default VM encoding and the specified line ending will be used.
      Parameters:
      file - the file to write to
      lines - the lines to write, null entries produce blank lines
      lineEnding - the line separator to use, null is system default
      Throws:
      IOException - in case of an I/O error
      Since:
      1.3
    • writeLines

      public static void writeLines(File file, Collection<?> lines, String lineEnding, boolean append) throws IOException
      Writes the toString() value of each item in a collection to the specified File line by line. The default VM encoding and the specified line ending will be used.
      Parameters:
      file - the file to write to
      lines - the lines to write, null entries produce blank lines
      lineEnding - the line separator to use, null is system default
      append - if true, then the lines will be added to the end of the file rather than overwriting
      Throws:
      IOException - in case of an I/O error
      Since:
      2.1
    • writeLines

      public static void writeLines(File file, String charsetName, Collection<?> lines) throws IOException
      Writes the toString() value of each item in a collection to the specified File line by line. The specified character encoding and the default line ending will be used.

      NOTE: As from v1.3, the parent directories of the file will be created if they do not exist.

      Parameters:
      file - the file to write to
      charsetName - the name of the requested charset, null means platform default
      lines - the lines to write, null entries produce blank lines
      Throws:
      IOException - in case of an I/O error
      UnsupportedEncodingException - if the encoding is not supported by the VM
      Since:
      1.1
    • writeLines

      public static void writeLines(File file, String charsetName, Collection<?> lines, boolean append) throws IOException
      Writes the toString() value of each item in a collection to the specified File line by line, optionally appending. The specified character encoding and the default line ending will be used.
      Parameters:
      file - the file to write to
      charsetName - the name of the requested charset, null means platform default
      lines - the lines to write, null entries produce blank lines
      append - if true, then the lines will be added to the end of the file rather than overwriting
      Throws:
      IOException - in case of an I/O error
      UnsupportedEncodingException - if the encoding is not supported by the VM
      Since:
      2.1
    • writeLines

      public static void writeLines(File file, String charsetName, Collection<?> lines, String lineEnding) throws IOException
      Writes the toString() value of each item in a collection to the specified File line by line. The specified character encoding and the line ending will be used.

      NOTE: As from v1.3, the parent directories of the file will be created if they do not exist.

      Parameters:
      file - the file to write to
      charsetName - the name of the requested charset, null means platform default
      lines - the lines to write, null entries produce blank lines
      lineEnding - the line separator to use, null is system default
      Throws:
      IOException - in case of an I/O error
      UnsupportedEncodingException - if the encoding is not supported by the VM
      Since:
      1.1
    • writeLines

      public static void writeLines(File file, String charsetName, Collection<?> lines, String lineEnding, boolean append) throws IOException
      Writes the toString() value of each item in a collection to the specified File line by line. The specified character encoding and the line ending will be used.
      Parameters:
      file - the file to write to
      charsetName - the name of the requested charset, null means platform default
      lines - the lines to write, null entries produce blank lines
      lineEnding - the line separator to use, null is system default
      append - if true, then the lines will be added to the end of the file rather than overwriting
      Throws:
      IOException - in case of an I/O error
      UnsupportedEncodingException - if the encoding is not supported by the VM
      Since:
      2.1
    • writeStringToFile

      @Deprecated public static void writeStringToFile(File file, String data) throws IOException
      Deprecated.
      2.5 use writeStringToFile(File, String, Charset) instead (and specify the appropriate encoding)
      Writes a String to a file creating the file if it does not exist using the default encoding for the VM.
      Parameters:
      file - the file to write
      data - the content to write to the file
      Throws:
      IOException - in case of an I/O error
    • writeStringToFile

      @Deprecated public static void writeStringToFile(File file, String data, boolean append) throws IOException
      Deprecated.
      2.5 use writeStringToFile(File, String, Charset, boolean) instead (and specify the appropriate encoding)
      Writes a String to a file creating the file if it does not exist using the default encoding for the VM.
      Parameters:
      file - the file to write
      data - the content to write to the file
      append - if true, then the String will be added to the end of the file rather than overwriting
      Throws:
      IOException - in case of an I/O error
      Since:
      2.1
    • writeStringToFile

      public static void writeStringToFile(File file, String data, Charset charset) throws IOException
      Writes a String to a file creating the file if it does not exist.

      NOTE: As from v1.3, the parent directories of the file will be created if they do not exist.

      Parameters:
      file - the file to write
      data - the content to write to the file
      charset - the charset to use, null means platform default
      Throws:
      IOException - in case of an I/O error
      UnsupportedEncodingException - if the encoding is not supported by the VM
      Since:
      2.4
    • writeStringToFile

      public static void writeStringToFile(File file, String data, Charset charset, boolean append) throws IOException
      Writes a String to a file creating the file if it does not exist.
      Parameters:
      file - the file to write
      data - the content to write to the file
      charset - the charset to use, null means platform default
      append - if true, then the String will be added to the end of the file rather than overwriting
      Throws:
      IOException - in case of an I/O error
      Since:
      2.3
    • writeStringToFile

      public static void writeStringToFile(File file, String data, String charsetName) throws IOException
      Writes a String to a file creating the file if it does not exist.

      NOTE: As from v1.3, the parent directories of the file will be created if they do not exist.

      Parameters:
      file - the file to write
      data - the content to write to the file
      charsetName - the name of the requested charset, null means platform default
      Throws:
      IOException - in case of an I/O error
      UnsupportedEncodingException - if the encoding is not supported by the VM
    • writeStringToFile

      public static void writeStringToFile(File file, String data, String charsetName, boolean append) throws IOException
      Writes a String to a file creating the file if it does not exist.
      Parameters:
      file - the file to write
      data - the content to write to the file
      charsetName - the name of the requested charset, null means platform default
      append - if true, then the String will be added to the end of the file rather than overwriting
      Throws:
      IOException - in case of an I/O error
      UnsupportedCharsetException - thrown instead of .UnsupportedEncodingException in version 2.2 if the encoding is not supported by the VM
      Since:
      2.1