org.apache.hadoop.fs

Class FileUtil

java.lang.Object

org.apache.hadoop.fs.FileUtil

@InterfaceAudience.Public
@InterfaceStability.Evolving
public class FileUtil
extends Object

A collection of file-processing util methods

Constructor Summary

Constructors

Constructor and Description
FileUtil()

Method Summary

Methods

Modifier and Type	Method and Description
static int	chmod(String filename, String perm) Change the permissions on a filename.
static int	chmod(String filename, String perm, boolean recursive) Change the permissions on a file / directory, recursively, if needed.
static boolean	copy(File src, FileSystem dstFS, Path dst, boolean deleteSource, Configuration conf) Copy local files to a FileSystem.
static boolean	copy(FileSystem srcFS, Path[] srcs, FileSystem dstFS, Path dst, boolean deleteSource, boolean overwrite, Configuration conf)
static boolean	copy(FileSystem srcFS, Path src, File dst, boolean deleteSource, Configuration conf) Copy FileSystem files to local files.
static boolean	copy(FileSystem srcFS, Path src, FileSystem dstFS, Path dst, boolean deleteSource, boolean overwrite, Configuration conf) Copy files between FileSystems.
static boolean	copy(FileSystem srcFS, Path src, FileSystem dstFS, Path dst, boolean deleteSource, Configuration conf) Copy files between FileSystems.
static boolean	copyMerge(FileSystem srcFS, Path srcDir, FileSystem dstFS, Path dstFile, boolean deleteSource, Configuration conf, String addString) Copy all files in a directory to one output file (merge).
static File	createLocalTempFile(File basefile, String prefix, boolean isDeleteOnExit) Create a tmp file for a base file.
static boolean	fullyDelete(File dir) Delete a directory and all its contents.
static boolean	fullyDelete(File dir, boolean tryGrantPermissions) Delete a directory and all its contents.
static void	fullyDelete(FileSystem fs, Path dir) Deprecated. Use FileSystem.delete(Path, boolean)
static boolean	fullyDeleteContents(File dir) Delete the contents of a directory, not the directory itself.
static boolean	fullyDeleteContents(File dir, boolean tryGrantPermissions) Delete the contents of a directory, not the directory itself.
static long	getDU(File dir) Takes an input dir and returns the du on that local directory.
static String[]	list(File dir) A wrapper for File.list().
static File[]	listFiles(File dir) A wrapper for File.listFiles().
static String	makeShellPath(File file) Convert a os-native filename to a path that works for the shell.
static String	makeShellPath(File file, boolean makeCanonicalPath) Convert a os-native filename to a path that works for the shell.
static String	makeShellPath(String filename) Convert a os-native filename to a path that works for the shell.
static void	replaceFile(File src, File target) Move the src file to the name specified by target.
static Path[]	stat2Paths(FileStatus[] stats) convert an array of FileStatus to an array of Path
static Path[]	stat2Paths(FileStatus[] stats, Path path) convert an array of FileStatus to an array of Path.
static int	symLink(String target, String linkname) Create a soft link between a src and destination only on a local disk.
static void	unTar(File inFile, File untarDir) Given a Tar File as input it will untar the file in a the untar directory passed as the second parameter This utility will untar ".tar" files and ".tar.gz","tgz" files.
static void	unZip(File inFile, File unzipDir) Given a File input it will unzip the file in a the unzip directory passed as the second parameter

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

FileUtil

public FileUtil()

Method Detail

stat2Paths

public static Path[] stat2Paths(FileStatus[] stats)

convert an array of FileStatus to an array of Path

Parameters:

stats - an array of FileStatus objects

Returns:

an array of paths corresponding to the input

stat2Paths

public static Path[] stat2Paths(FileStatus[] stats,
                Path path)

convert an array of FileStatus to an array of Path. If stats if null, return path

Parameters:

stats - an array of FileStatus objects

path - default path to return in stats is null

Returns:

an array of paths corresponding to the input

fullyDelete

public static boolean fullyDelete(File dir)

Delete a directory and all its contents. If we return false, the directory may be partially-deleted. (1) If dir is symlink to a file, the symlink is deleted. The file pointed to by the symlink is not deleted. (2) If dir is symlink to a directory, symlink is deleted. The directory pointed to by symlink is not deleted. (3) If dir is a normal file, it is deleted. (4) If dir is a normal directory, then dir and all its contents recursively are deleted.

fullyDelete

public static boolean fullyDelete(File dir,
                  boolean tryGrantPermissions)

Delete a directory and all its contents. If we return false, the directory may be partially-deleted. (1) If dir is symlink to a file, the symlink is deleted. The file pointed to by the symlink is not deleted. (2) If dir is symlink to a directory, symlink is deleted. The directory pointed to by symlink is not deleted. (3) If dir is a normal file, it is deleted. (4) If dir is a normal directory, then dir and all its contents recursively are deleted.

Parameters:

dir - the file or directory to be deleted

tryGrantPermissions - true if permissions should be modified to delete a file.

Returns:

true on success false on failure.

fullyDeleteContents

public static boolean fullyDeleteContents(File dir)

Delete the contents of a directory, not the directory itself. If we return false, the directory may be partially-deleted. If dir is a symlink to a directory, all the contents of the actual directory pointed to by dir will be deleted.

fullyDeleteContents

public static boolean fullyDeleteContents(File dir,
                          boolean tryGrantPermissions)

Delete the contents of a directory, not the directory itself. If we return false, the directory may be partially-deleted. If dir is a symlink to a directory, all the contents of the actual directory pointed to by dir will be deleted.

Parameters:

tryGrantPermissions - if 'true', try grant +rwx permissions to this and all the underlying directories before trying to delete their contents.

fullyDelete

@Deprecated
public static void fullyDelete(FileSystem fs,
                          Path dir)
                        throws IOException

Deprecated. Use FileSystem.delete(Path, boolean)

Recursively delete a directory.

Parameters:

fs - FileSystem on which the path is present

dir - directory to recursively delete

Throws:

IOException

copy

public static boolean copy(FileSystem srcFS,
           Path src,
           FileSystem dstFS,
           Path dst,
           boolean deleteSource,
           Configuration conf)
                    throws IOException

Copy files between FileSystems.

Throws:

IOException

copy

public static boolean copy(FileSystem srcFS,
           Path[] srcs,
           FileSystem dstFS,
           Path dst,
           boolean deleteSource,
           boolean overwrite,
           Configuration conf)
                    throws IOException

Throws:

IOException

copy

public static boolean copy(FileSystem srcFS,
           Path src,
           FileSystem dstFS,
           Path dst,
           boolean deleteSource,
           boolean overwrite,
           Configuration conf)
                    throws IOException

Copy files between FileSystems.

Throws:

IOException

copyMerge

public static boolean copyMerge(FileSystem srcFS,
                Path srcDir,
                FileSystem dstFS,
                Path dstFile,
                boolean deleteSource,
                Configuration conf,
                String addString)
                         throws IOException

Copy all files in a directory to one output file (merge).

Throws:

IOException

copy

public static boolean copy(File src,
           FileSystem dstFS,
           Path dst,
           boolean deleteSource,
           Configuration conf)
                    throws IOException

Copy local files to a FileSystem.

Throws:

IOException

copy

public static boolean copy(FileSystem srcFS,
           Path src,
           File dst,
           boolean deleteSource,
           Configuration conf)
                    throws IOException

Copy FileSystem files to local files.

Throws:

IOException

makeShellPath

public static String makeShellPath(String filename)
                            throws IOException

Convert a os-native filename to a path that works for the shell.

Parameters:

filename - The filename to convert

Returns:

The unix pathname

Throws:

IOException - on windows, there can be problems with the subprocess

makeShellPath

public static String makeShellPath(File file)
                            throws IOException

Convert a os-native filename to a path that works for the shell.

Parameters:

file - The filename to convert

Returns:

The unix pathname

Throws:

IOException - on windows, there can be problems with the subprocess

makeShellPath

public static String makeShellPath(File file,
                   boolean makeCanonicalPath)
                            throws IOException

Convert a os-native filename to a path that works for the shell.

Parameters:

file - The filename to convert

makeCanonicalPath - Whether to make canonical path for the file passed

Returns:

The unix pathname

Throws:

IOException - on windows, there can be problems with the subprocess

getDU

public static long getDU(File dir)

Takes an input dir and returns the du on that local directory. Very basic implementation.

Parameters:

dir - The input dir to get the disk space of this local dir

Returns:

The total disk space of the input local directory

unZip

public static void unZip(File inFile,
         File unzipDir)
                  throws IOException

Given a File input it will unzip the file in a the unzip directory passed as the second parameter

Parameters:

inFile - The zip file as input

unzipDir - The unzip directory where to unzip the zip file.

Throws:

IOException

unTar

public static void unTar(File inFile,
         File untarDir)
                  throws IOException

Given a Tar File as input it will untar the file in a the untar directory passed as the second parameter This utility will untar ".tar" files and ".tar.gz","tgz" files.

Parameters:

inFile - The tar file as input.

untarDir - The untar directory where to untar the tar file.

Throws:

IOException

symLink

public static int symLink(String target,
          String linkname)
                   throws IOException

Create a soft link between a src and destination only on a local disk. HDFS does not support this

Parameters:

target - the target for symlink

linkname - the symlink

Returns:

value returned by the command

Throws:

IOException

chmod

public static int chmod(String filename,
        String perm)
                 throws IOException,
                        InterruptedException

Change the permissions on a filename.

Parameters:

filename - the name of the file to change

perm - the permission string

Returns:

the exit code from the command

Throws:

IOException

InterruptedException

chmod

public static int chmod(String filename,
        String perm,
        boolean recursive)
                 throws IOException,
                        InterruptedException

Change the permissions on a file / directory, recursively, if needed.

Parameters:

filename - name of the file whose permissions are to change

perm - permission string

recursive - true, if permissions should be changed recursively

Returns:

the exit code from the command.

Throws:

IOException

InterruptedException

createLocalTempFile

public static final File createLocalTempFile(File basefile,
                       String prefix,
                       boolean isDeleteOnExit)
                                      throws IOException

Create a tmp file for a base file.

Parameters:

basefile - the base file of the tmp

prefix - file name prefix of tmp

isDeleteOnExit - if true, the tmp will be deleted when the VM exits

Returns:

a newly created tmp file

Throws:

IOException - If a tmp file cannot created

See Also:

File.createTempFile(String, String, File), File.deleteOnExit()

replaceFile

public static void replaceFile(File src,
               File target)
                        throws IOException

Move the src file to the name specified by target.

Parameters:

src - the source file

target - the target file

Throws:

IOException - If this operation fails

listFiles

public static File[] listFiles(File dir)
                        throws IOException

A wrapper for File.listFiles(). This java.io API returns null when a dir is not a directory or for any I/O error. Instead of having null check everywhere File#listFiles() is used, we will add utility API to get around this problem. For the majority of cases where we prefer an IOException to be thrown.

Parameters:

dir - directory for which listing should be performed

Returns:

list of files or empty list

Throws:

IOException - for invalid directory or for a bad disk.

list

public static String[] list(File dir)
                     throws IOException

A wrapper for File.list(). This java.io API returns null when a dir is not a directory or for any I/O error. Instead of having null check everywhere File#list() is used, we will add utility API to get around this problem. For the majority of cases where we prefer an IOException to be thrown.

Parameters:

dir - directory for which listing should be performed

Returns:

list of file names or empty string list

Throws:

IOException - for invalid directory or for a bad disk.