org.zeroturnaround.zip.commons

Class FileUtils

java.lang.Object

org.zeroturnaround.zip.commons.FileUtils

public class FileUtils
extends Object

This is a class that has been made significantly smaller (deleted a bunch of methods) and originally is from the Apache commons-io package. All license and other documentation is intact. 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

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

Fields

Modifier and Type	Field and Description
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

Constructors

Constructor and Description
FileUtils() Instances should NOT be constructed in standard programming.

Method Summary

Methods

Modifier and Type	Method and Description
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 void	copy(File file, OutputStream out) Copies the given file into an output stream.
static void	copy(InputStream in, File file) Copies the given input stream into a file.
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, boolean preserveFileDate) Copies a filtered directory to a new location.
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	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 File	getTempFileFor(File file) Find a non-existing file in the same directory using the same name as prefix.
static void	moveDirectory(File srcDir, File destDir) Moves a directory.
static void	moveFile(File srcFile, File destFile) Moves a file.
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 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 long	sizeOfDirectory(File directory) Counts the size of a directory recursively (sum of the length of all files).

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

copy

public static void copy(File file,
        OutputStream out)
                 throws IOException

Copies the given file into an output stream.

Parameters:

file - input file (must exist).

out - output stream.

Throws:

IOException

copy

public static void copy(InputStream in,
        File file)
                 throws IOException

Copies the given input stream into a file.

The target file must not be a directory and its parent must exist.

Parameters:

in - source stream.

file - output file to be created or overwritten.

Throws:

IOException

getTempFileFor

public static File getTempFileFor(File file)

Find a non-existing file in the same directory using the same name as prefix.

Parameters:

file - file used for the name and location (it is not read or written).

Returns:

a non-existing file in the same directory using the same name as prefix.

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

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

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)

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,
                 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

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:

• 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:

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

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

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:

• A directory to be deleted does not have to be empty.
• You get exceptions when a file or directory cannot be deleted. (java.io.File methods 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 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

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

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