org.apache.commons.io
Class FileUtils

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

public class FileUtils
extends Object

General file manipulation utilities.

Facilities are provided in the following areas:

Origin of code: Excalibur, Alexandria, Commons-Utils

Version:
$Id: FileUtils.java 610810 2008-01-10 15:04:49Z niallp $
Author:
Kevin A. Burton, Scott Sanders, Daniel Rall, Christoph.Reck, Peter Donald, Jeff Turner, Matthew Hawthorne, Jeremias Maerki, Stephen Colebourne, Ian Springer, Chris Eldredge, Jim Harrington, Niall Pemberton, Sandy McArthur

Field Summary
static File[] EMPTY_FILE_ARRAY
          An empty array of type File.
static long ONE_GB
          The number of bytes in a gigabyte.
static long ONE_KB
          The number of bytes in a kilobyte.
static long ONE_MB
          The number of bytes in a megabyte.
 
Constructor Summary
FileUtils()
          Instances should NOT be constructed in standard programming.
 
Method Summary
static String byteCountToDisplaySize(long size)
          Returns a human-readable version of the file size, where the input represents a specific number of bytes.
static Checksum checksum(File file, Checksum checksum)
          Computes the checksum of a file using the specified checksum object.
static long checksumCRC32(File file)
          Computes the checksum of a file using the CRC32 checksum routine.
static void cleanDirectory(File directory)
          Cleans a directory without deleting it.
static boolean contentEquals(File file1, File file2)
          Compares the contents of two files to determine if they are equal or not.
static File[] convertFileCollectionToFileArray(Collection files)
          Converts a Collection containing java.io.File instanced into array representation.
static void copyDirectory(File srcDir, File destDir)
          Copies a whole directory to a new location preserving the file dates.
static void copyDirectory(File srcDir, File destDir, boolean preserveFileDate)
          Copies a whole directory to a new location.
static void copyDirectory(File srcDir, File destDir, FileFilter filter)
          Copies a filtered directory to a new location preserving the file dates.
static void copyDirectory(File srcDir, File destDir, FileFilter filter, boolean preserveFileDate)
          Copies a filtered directory to a new location.
static void copyDirectoryToDirectory(File srcDir, File destDir)
          Copies a directory to within another directory preserving the file dates.
static void copyFile(File srcFile, File destFile)
          Copies a file to a new location preserving the file date.
static void copyFile(File srcFile, File destFile, boolean preserveFileDate)
          Copies a file to a new location.
static void copyFileToDirectory(File srcFile, File destDir)
          Copies a file to a directory preserving the file date.
static void copyFileToDirectory(File srcFile, File destDir, boolean preserveFileDate)
          Copies a file to a directory optionally preserving the file date.
static void copyURLToFile(URL source, File destination)
          Copies bytes from the URL source to a file destination.
static void deleteDirectory(File directory)
          Deletes a directory recursively.
static boolean deleteQuietly(File file)
          Deletes a file, never throwing an exception.
static void forceDelete(File file)
          Deletes a file.
static void forceDeleteOnExit(File file)
          Schedules a file to be deleted when JVM exits.
static void forceMkdir(File directory)
          Makes a directory, including any necessary but nonexistent parent directories.
static boolean isFileNewer(File file, Date date)
          Tests if the specified File is newer than the specified Date.
static boolean isFileNewer(File file, File reference)
          Tests if the specified File is newer than the reference File.
static boolean isFileNewer(File file, long timeMillis)
          Tests if the specified File is newer than the specified time reference.
static boolean isFileOlder(File file, Date date)
          Tests if the specified File is older than the specified Date.
static boolean isFileOlder(File file, File reference)
          Tests if the specified File is older than the reference File.
static boolean isFileOlder(File file, long timeMillis)
          Tests if the specified File is older than the specified time reference.
static Iterator iterateFiles(File directory, IOFileFilter fileFilter, IOFileFilter dirFilter)
          Allows iteration over the files in given directory (and optionally its subdirectories).
static Iterator 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.
static LineIterator lineIterator(File file)
          Returns an Iterator for the lines in a File using the default encoding for the VM.
static LineIterator lineIterator(File file, String encoding)
          Returns an Iterator for the lines in a File.
static Collection listFiles(File directory, IOFileFilter fileFilter, IOFileFilter dirFilter)
          Finds files within a given directory (and optionally its subdirectories).
static Collection listFiles(File directory, String[] extensions, boolean recursive)
          Finds files within a given directory (and optionally its subdirectories) which match an array of extensions.
static void moveDirectory(File srcDir, File destDir)
          Moves a directory.
static void moveDirectoryToDirectory(File src, File destDir, boolean createDestDir)
          Moves a directory to another directory.
static void moveFile(File srcFile, File destFile)
          Moves a file.
static void moveFileToDirectory(File srcFile, File destDir, boolean createDestDir)
          Moves a file to a directory.
static void moveToDirectory(File src, File destDir, boolean createDestDir)
          Moves a file or directory to the destination directory.
static FileInputStream openInputStream(File file)
          Opens a FileInputStream for the specified file, providing better error messages than simply calling new FileInputStream(file).
static FileOutputStream openOutputStream(File file)
          Opens a FileOutputStream for the specified file, checking and creating the parent directory if it does not exist.
static byte[] readFileToByteArray(File file)
          Reads the contents of a file into a byte array.
static String readFileToString(File file)
          Reads the contents of a file into a String using the default encoding for the VM.
static String readFileToString(File file, String encoding)
          Reads the contents of a file into a String.
static List readLines(File file)
          Reads the contents of a file line by line to a List of Strings using the default encoding for the VM.
static List readLines(File file, String encoding)
          Reads the contents of a file line by line to a List of Strings.
static long sizeOfDirectory(File directory)
          Counts the size of a directory recursively (sum of the length of all files).
static File toFile(URL url)
          Convert from a URL to a File.
static File[] toFiles(URL[] urls)
          Converts each of an array of URL to a File.
static void touch(File file)
          Implements the same behaviour as the "touch" utility on Unix.
static URL[] toURLs(File[] files)
          Converts each of an array of File to a URL.
static boolean waitFor(File file, int seconds)
          Waits for NFS to propagate a file creation, imposing a timeout.
static void writeByteArrayToFile(File file, byte[] data)
          Writes a byte array to a file creating the file if it does not exist.
static void writeLines(File file, Collection lines)
          Writes the toString() value of each item in a collection to the specified File line by line.
static void writeLines(File file, Collection lines, String lineEnding)
          Writes the toString() value of each item in a collection to the specified File line by line.
static void writeLines(File file, String encoding, Collection lines)
          Writes the toString() value of each item in a collection to the specified File line by line.
static void writeLines(File file, String encoding, Collection lines, String lineEnding)
          Writes the toString() value of each item in a collection to the specified File line by line.
static void writeStringToFile(File file, String data)
          Writes a String to a file creating the file if it does not exist using the default encoding for the VM.
static void writeStringToFile(File file, String data, String encoding)
          Writes a String to a file creating the file if it does not exist.
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

ONE_KB

public static final long ONE_KB
The number of bytes in a kilobyte.

See Also:
Constant Field Values

ONE_MB

public static final long ONE_MB
The number of bytes in a megabyte.

See Also:
Constant Field Values

ONE_GB

public static final long ONE_GB
The number of bytes in a gigabyte.

See Also:
Constant Field Values

EMPTY_FILE_ARRAY

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

Constructor Detail

FileUtils

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

Method Detail

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:
Commons IO 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:
Commons IO 1.3

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.

Parameters:
size - the number of bytes
Returns:
a human-readable display value (includes units)

touch

public static void touch(File file)
                  throws IOException
Implements the same behaviour 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

convertFileCollectionToFileArray

public static File[] convertFileCollectionToFileArray(Collection 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

listFiles

public static Collection 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.
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 collection of java.io.File with the matching files
See Also:
FileFilterUtils, NameFileFilter

iterateFiles

public static Iterator 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).

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:
Commons IO 1.2
See Also:
FileFilterUtils, NameFileFilter

listFiles

public static Collection 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:
an collection of java.io.File with the matching files

iterateFiles

public static Iterator 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).

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:
Commons IO 1.2

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

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.

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
Throws:
IllegalArgumentException - if the file is incorrectly encoded

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:
Commons IO 1.1

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
Returns:
an array of URLs matching the input
Throws:
IOException - if a file cannot be converted

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.

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:
copyFile(File, File, boolean)

copyFileToDirectory

public static void copyFileToDirectory(File srcFile,
                                       File destDir,
                                       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.

Parameters:
srcFile - an existing file to copy, must not be null
destDir - 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
Since:
Commons IO 1.3
See Also:
copyFile(File, File, boolean)

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.

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
See Also:
copyFileToDirectory(File, File)

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.

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
See Also:
copyFileToDirectory(File, File, boolean)

copyDirectoryToDirectory

public static void copyDirectoryToDirectory(File srcDir,
                                            File destDir)
                                     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.

Parameters:
srcDir - an existing directory 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
Since:
Commons IO 1.2

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.

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:
Commons IO 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.

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:
Commons IO 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.

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:
Commons IO 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.

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:
Commons IO 1.4

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.

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

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

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:

Parameters:
file - file or directory to delete, can be null
Returns:
true if the file or directory was deleted, otherwise false
Since:
Commons IO 1.4

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

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

readFileToString

public static String readFileToString(File file,
                                      String encoding)
                               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
encoding - the encoding to use, null means platform default
Returns:
the file contents, never null
Throws:
IOException - in case of an I/O error
UnsupportedEncodingException - if the encoding is not supported by the VM

readFileToString

public static String readFileToString(File file)
                               throws IOException
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:
Commons IO 1.3.1

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:
Commons IO 1.1

readLines

public static List readLines(File file,
                             String encoding)
                      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
encoding - the encoding 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
UnsupportedEncodingException - if the encoding is not supported by the VM
Since:
Commons IO 1.1

readLines

public static List readLines(File file)
                      throws IOException
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:
Commons IO 1.3

lineIterator

public static LineIterator lineIterator(File file,
                                        String encoding)
                                 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
encoding - the encoding to use, 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:
Commons IO 1.2

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:
Commons IO 1.3
See Also:
lineIterator(File, String)

writeStringToFile

public static void writeStringToFile(File file,
                                     String data,
                                     String encoding)
                              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
encoding - the encoding 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

writeStringToFile

public static void writeStringToFile(File file,
                                     String data)
                              throws IOException
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

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:
Commons IO 1.1

writeLines

public static void writeLines(File file,
                              String encoding,
                              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
encoding - the encoding to use, 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:
Commons IO 1.1

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:
Commons IO 1.3

writeLines

public static void writeLines(File file,
                              String encoding,
                              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
encoding - the encoding to use, 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:
Commons IO 1.1

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:
Commons IO 1.3

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:

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 there already exists a file with specified name or the directory cannot be created then an exception 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

sizeOfDirectory

public static long sizeOfDirectory(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

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, must not be null
reference - the File of which the modification date is used, must not be null
Returns:
true if the File exists and has been modified more recently than the reference File
Throws:
IllegalArgumentException - if the file is null
IllegalArgumentException - if the reference file is null or doesn't exist

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, must not be null
date - the date reference, must not be null
Returns:
true if the File exists and has been modified after the given Date.
Throws:
IllegalArgumentException - if the file is null
IllegalArgumentException - if the date is null

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, must not be null
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:
IllegalArgumentException - if the file 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, must not be null
reference - the File of which the modification date is used, must not be null
Returns:
true if the File exists and has been modified before the reference File
Throws:
IllegalArgumentException - if the file is null
IllegalArgumentException - if the reference file is null or doesn't exist

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, must not be null
date - the date reference, must not be null
Returns:
true if the File exists and has been modified before the given Date.
Throws:
IllegalArgumentException - if the file is null
IllegalArgumentException - if the date is null

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, must not be null
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:
IllegalArgumentException - if the file is null

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:
Commons IO 1.3

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:
Commons IO 1.3

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
IOException - if source or destination is invalid
IOException - if an IO error occurs moving the file
Since:
Commons IO 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
IOException - if source or destination is invalid
IOException - if an IO error occurs moving the file
Since:
Commons IO 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
IOException - if source or destination is invalid
IOException - if an IO error occurs moving the file
Since:
Commons IO 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
IOException - if source or destination is invalid
IOException - if an IO error occurs moving the file
Since:
Commons IO 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
IOException - if source or destination is invalid
IOException - if an IO error occurs moving the file
Since:
Commons IO 1.4


Copyright 2002-2008 The Apache Software Foundation. All Rights Reserved.