java hadoop file system API

时间：2022-09-26 14:15:37
org.apache.hadoop.fs

Class FileSystem

  • All Implemented Interfaces:
    Closeable, AutoCloseable, Configurable
    Direct Known Subclasses:
    FilterFileSystem, FTPFileSystem, KosmosFileSystem, NativeS3FileSystem, RawLocalFileSystem, S3FileSystem, ViewFileSystem 
    @InterfaceAudience.Public
    
@InterfaceStability.Stable
    
public abstract class FileSystem
    
extends Configured
    
implements Closeable
    An abstract base class for a fairly generic filesystem. It may be implemented as a distributed filesystem, or as a "local" one that reflects the locally-connected disk. The local version exists for small Hadoop instances and for testing.

    All user code that may potentially use the Hadoop Distributed File System should be written to use a FileSystem object. The Hadoop DFS is a multi-machine system that appears as a single disk. It's useful because of its fault tolerance and potentially very large capacity.

    The local implementation is LocalFileSystem and distributed implementation is DistributedFileSystem.

    • Constructor Detail

    • Method Detail

      • getDefaultUri

        public static URI getDefaultUri(Configuration conf)
        Get the default filesystem URI from a configuration.
        Parameters:
        conf - the configuration to use
        Returns:
        the uri of the default filesystem

      • setDefaultUri

        public static void setDefaultUri(Configuration conf,
        URI uri)
        Set the default filesystem URI in a configuration.
        Parameters:
        conf - the configuration to alter
        uri - the new default filesystem uri

      • setDefaultUri

        public static void setDefaultUri(Configuration conf,
        String uri)
        Set the default filesystem URI in a configuration.
        Parameters:
        conf - the configuration to alter
        uri - the new default filesystem uri

      • initialize

        public void initialize(URI name,
        Configuration conf)
        
                throws IOException
        Called after a new FileSystem instance is constructed.
        Parameters:
        name - a uri whose authority section names the host, port, etc. for this FileSystem
        conf - the configuration
        Throws:
        IOException

      • getScheme

        public String getScheme()
        Return the protocol scheme for the FileSystem.

        This implementation throws an UnsupportedOperationException.

        Returns:
        the protocol scheme for the FileSystem.

      • getUri

        public abstract URI getUri()
        Returns a URI whose scheme and authority identify this FileSystem.

      • getCanonicalUri

        protected URI getCanonicalUri()
        Resolve the uri's hostname and add the default port if not in the uri
        Returns:
        URI
        See Also:
        NetUtils.getCanonicalUri(URI, int)

      • getDefaultPort

        protected int getDefaultPort()
        Get the default port for this file system.
        Returns:
        the default port or 0 if there isn't one

      • get

        public static FileSystem get(URI uri,
        Configuration conf)
        
                      throws IOException
        Returns the FileSystem for this URI's scheme and authority. The scheme of the URI determines a configuration property name, fs.scheme.class whose value names the FileSystem class. The entire URI is passed to the FileSystem instance's initialize method.
        Throws:
        IOException

      • newInstance

        public static FileSystem newInstance(URI uri,
        Configuration conf)
        
                              throws IOException
        Returns the FileSystem for this URI's scheme and authority. The scheme of the URI determines a configuration property name, fs.scheme.class whose value names the FileSystem class. The entire URI is passed to the FileSystem instance's initialize method. This always returns a new FileSystem object.
        Throws:
        IOException

      • closeAll

        public static void closeAll()
        
                     throws IOException
        Close all cached filesystems. Be sure those filesystems are not used anymore.
        Throws:
        IOException

      • closeAllForUGI

        public static void closeAllForUGI(org.apache.hadoop.security.UserGroupInformation ugi)
        
                           throws IOException
        Close all cached filesystems for a given UGI. Be sure those filesystems are not used anymore.
        Parameters:
        ugi - user group info to close
        Throws:
        IOException

      • makeQualified

        public Path makeQualified(Path path)
        Make sure that a path specifies a FileSystem.
        Parameters:
        path - to use

      • create

        public static FSDataOutputStream create(FileSystem fs,
        Path file,
        FsPermission permission)
        
                                 throws IOException
        create a file with the provided permission The permission of the file is set to be the provided permission as in setPermission, not permission&~umask It is implemented using two RPCs. It is understood that it is inefficient, but the implementation is thread-safe. The other option is to change the value of umask in configuration to be 0, but it is not thread-safe.
        Parameters:
        fs - file system handle
        file - the name of the file to be created
        permission - the permission of the file
        Returns:
        an output stream
        Throws:
        IOException

      • mkdirs

        public static boolean mkdirs(FileSystem fs,
        Path dir,
        FsPermission permission)
        
                      throws IOException
        create a directory with the provided permission The permission of the directory is set to be the provided permission as in setPermission, not permission&~umask
        Parameters:
        fs - file system handle
        dir - the name of the directory to be created
        permission - the permission of the directory
        Returns:
        true if the directory creation succeeds; false otherwise
        Throws:
        IOException
        See Also:
        create(FileSystem, Path, FsPermission)

      • checkPath

        protected void checkPath(Path path)
        Check that a Path belongs to this FileSystem.
        Parameters:
        path - to check

      • getFileBlockLocations

        public BlockLocation[] getFileBlockLocations(FileStatus file,
        
                                    long start,
        
                                    long len)
        
                                      throws IOException
        Return an array containing hostnames, offset and size of portions of the given file. For a nonexistent file or regions, null will be returned. This call is most helpful with DFS, where it returns hostnames of machines that contain the given file. The FileSystem will simply return an elt containing 'localhost'.
        Parameters:
        file - FilesStatus to get data from
        start - offset into the given file
        len - length for which to get locations for
        Throws:
        IOException

      • getFileBlockLocations

        public BlockLocation[] getFileBlockLocations(Path p,
        
                                    long start,
        
                                    long len)
        
                                      throws IOException
        Return an array containing hostnames, offset and size of portions of the given file. For a nonexistent file or regions, null will be returned. This call is most helpful with DFS, where it returns hostnames of machines that contain the given file. The FileSystem will simply return an elt containing 'localhost'.
        Parameters:
        p - path is used to identify an FS since an FS could have another FS that it could be delegating the call to
        start - offset into the given file
        len - length for which to get locations for
        Throws:
        IOException

      • getServerDefaults

        public FsServerDefaults getServerDefaults(Path p)
        
                                   throws IOException
        Return a set of server default configuration values
        Parameters:
        p - path is used to identify an FS since an FS could have another FS that it could be delegating the call to
        Returns:
        server default configuration values
        Throws:
        IOException

      • open

        public abstract FSDataInputStream open(Path f,
        
                     int bufferSize)
        
                                throws IOException
        Opens an FSDataInputStream at the indicated Path.
        Parameters:
        f - the file name to open
        bufferSize - the size of the buffer to be used.
        Throws:
        IOException

      • create

        public FSDataOutputStream create(Path f,
        
                        boolean overwrite)
        
                          throws IOException
        Create an FSDataOutputStream at the indicated Path.
        Parameters:
        f - the file to create
        overwrite - if a file with this name already exists, then if true, the file will be overwritten, and if false an exception will be thrown.
        Throws:
        IOException

      • create

        public FSDataOutputStream create(Path f,
        
                        short replication)
        
                          throws IOException
        Create an FSDataOutputStream at the indicated Path. Files are overwritten by default.
        Parameters:
        f - the file to create
        replication - the replication factor
        Throws:
        IOException

      • create

        public FSDataOutputStream create(Path f,
        
                        short replication,
        Progressable progress)
        
                          throws IOException
        Create an FSDataOutputStream at the indicated Path with write-progress reporting. Files are overwritten by default.
        Parameters:
        f - the file to create
        replication - the replication factor
        progress - to report progress
        Throws:
        IOException

      • create

        public FSDataOutputStream create(Path f,
        
                        boolean overwrite,
        
                        int bufferSize)
        
                          throws IOException
        Create an FSDataOutputStream at the indicated Path.
        Parameters:
        f - the file name to create
        overwrite - if a file with this name already exists, then if true, the file will be overwritten, and if false an error will be thrown.
        bufferSize - the size of the buffer to be used.
        Throws:
        IOException

      • create

        public FSDataOutputStream create(Path f,
        
                        boolean overwrite,
        
                        int bufferSize,
        Progressable progress)
        
                          throws IOException
        Create an FSDataOutputStream at the indicated Path with write-progress reporting.
        Parameters:
        f - the path of the file to open
        overwrite - if a file with this name already exists, then if true, the file will be overwritten, and if false an error will be thrown.
        bufferSize - the size of the buffer to be used.
        Throws:
        IOException

      • create

        public FSDataOutputStream create(Path f,
        
                        boolean overwrite,
        
                        int bufferSize,
        
                        short replication,
        
                        long blockSize)
        
                          throws IOException
        Create an FSDataOutputStream at the indicated Path.
        Parameters:
        f - the file name to open
        overwrite - if a file with this name already exists, then if true, the file will be overwritten, and if false an error will be thrown.
        bufferSize - the size of the buffer to be used.
        replication - required block replication for the file.
        Throws:
        IOException

      • create

        public FSDataOutputStream create(Path f,
        
                        boolean overwrite,
        
                        int bufferSize,
        
                        short replication,
        
                        long blockSize,
        Progressable progress)
        
                          throws IOException
        Create an FSDataOutputStream at the indicated Path with write-progress reporting.
        Parameters:
        f - the file name to open
        overwrite - if a file with this name already exists, then if true, the file will be overwritten, and if false an error will be thrown.
        bufferSize - the size of the buffer to be used.
        replication - required block replication for the file.
        Throws:
        IOException

      • create

        public abstract FSDataOutputStream create(Path f,
        FsPermission permission,
        
                        boolean overwrite,
        
                        int bufferSize,
        
                        short replication,
        
                        long blockSize,
        Progressable progress)
        
                                   throws IOException
        Create an FSDataOutputStream at the indicated Path with write-progress reporting.
        Parameters:
        f - the file name to open
        permission -
        overwrite - if a file with this name already exists, then if true, the file will be overwritten, and if false an error will be thrown.
        bufferSize - the size of the buffer to be used.
        replication - required block replication for the file.
        blockSize -
        progress -
        Throws:
        IOException
        See Also:
        setPermission(Path, FsPermission)

      • create

        public FSDataOutputStream create(Path f,
        FsPermission permission,
        EnumSet<CreateFlag> flags,
        
                        int bufferSize,
        
                        short replication,
        
                        long blockSize,
        Progressable progress,
        
                        org.apache.hadoop.fs.Options.ChecksumOpt checksumOpt)
        
                          throws IOException
        Create an FSDataOutputStream at the indicated Path with a custom checksum option
        Parameters:
        f - the file name to open
        permission -
        flags - CreateFlags to use for this stream.
        bufferSize - the size of the buffer to be used.
        replication - required block replication for the file.
        blockSize -
        progress -
        checksumOpt - checksum parameter. If null, the values found in conf will be used.
        Throws:
        IOException
        See Also:
        setPermission(Path, FsPermission)

      • primitiveMkdir

        @Deprecated
        
protected boolean primitiveMkdir(Path f,
        FsPermission absolutePermission)
        
                          throws IOException
        Deprecated. 
        This version of the mkdirs method assumes that the permission is absolute. It has been added to support the FileContext that processes the permission with umask before calling this method. This a temporary method added to support the transition from FileSystem to FileContext for user applications.
        Throws:
        IOException

      • primitiveMkdir

        @Deprecated
        
protected void primitiveMkdir(Path f,
        FsPermission absolutePermission,
        
                             boolean createParent)
        
                       throws IOException
        Deprecated. 
        This version of the mkdirs method assumes that the permission is absolute. It has been added to support the FileContext that processes the permission with umask before calling this method. This a temporary method added to support the transition from FileSystem to FileContext for user applications.
        Throws:
        IOException

      • createNonRecursive

        @Deprecated
        
public FSDataOutputStream createNonRecursive(Path f,
        
                                               boolean overwrite,
        
                                               int bufferSize,
        
                                               short replication,
        
                                               long blockSize,
        Progressable progress)
        
                                      throws IOException
        Deprecated. API only for 0.20-append
        Opens an FSDataOutputStream at the indicated Path with write-progress reporting. Same as create(), except fails if parent directory doesn't already exist.
        Parameters:
        f - the file name to open
        overwrite - if a file with this name already exists, then if true, the file will be overwritten, and if false an error will be thrown.
        bufferSize - the size of the buffer to be used.
        replication - required block replication for the file.
        blockSize -
        progress -
        Throws:
        IOException
        See Also:
        setPermission(Path, FsPermission)

      • createNonRecursive

        @Deprecated
        
public FSDataOutputStream createNonRecursive(Path f,
        FsPermission permission,
        
                                               boolean overwrite,
        
                                               int bufferSize,
        
                                               short replication,
        
                                               long blockSize,
        Progressable progress)
        
                                      throws IOException
        Deprecated. API only for 0.20-append
        Opens an FSDataOutputStream at the indicated Path with write-progress reporting. Same as create(), except fails if parent directory doesn't already exist.
        Parameters:
        f - the file name to open
        permission -
        overwrite - if a file with this name already exists, then if true, the file will be overwritten, and if false an error will be thrown.
        bufferSize - the size of the buffer to be used.
        replication - required block replication for the file.
        blockSize -
        progress -
        Throws:
        IOException
        See Also:
        setPermission(Path, FsPermission)

      • createNewFile

        public boolean createNewFile(Path f)
        
                      throws IOException
        Creates the given Path as a brand-new zero-length file. If create fails, or if it already existed, return false.
        Parameters:
        f - path to use for create
        Throws:
        IOException

      • append

        public FSDataOutputStream append(Path f)
        
                          throws IOException
        Append to an existing file (optional operation). Same as append(f, getConf().getInt("io.file.buffer.size", 4096), null)
        Parameters:
        f - the existing file to be appended.
        Throws:
        IOException

      • append

        public FSDataOutputStream append(Path f,
        
                        int bufferSize)
        
                          throws IOException
        Append to an existing file (optional operation). Same as append(f, bufferSize, null).
        Parameters:
        f - the existing file to be appended.
        bufferSize - the size of the buffer to be used.
        Throws:
        IOException

      • append

        public abstract FSDataOutputStream append(Path f,
        
                        int bufferSize,
        Progressable progress)
        
                                   throws IOException
        Append to an existing file (optional operation).
        Parameters:
        f - the existing file to be appended.
        bufferSize - the size of the buffer to be used.
        progress - for reporting progress if it is not null.
        Throws:
        IOException

      • concat

        public void concat(Path trg,
        Path[] psrcs)
        
            throws IOException
        Concat existing files together.
        Parameters:
        trg - the path to the target destination.
        psrcs - the paths to the sources to use for the concatenation.
        Throws:
        IOException

      • setReplication

        public boolean setReplication(Path src,
        
                     short replication)
        
                       throws IOException
        Set replication for an existing file.
        Parameters:
        src - file name
        replication - new replication
        Returns:
        true if successful; false if file does not exist or is a directory
        Throws:
        IOException

      • rename

        public abstract boolean rename(Path src,
        Path dst)
        
                        throws IOException
        Renames Path src to Path dst. Can take place on local fs or remote DFS.
        Parameters:
        src - path to be renamed
        dst - new path after rename
        Returns:
        true if rename is successful
        Throws:
        IOException - on failure

      • rename

        @Deprecated
        
protected void rename(Path src,
        Path dst,
        
                     org.apache.hadoop.fs.Options.Rename... options)
        
               throws IOException
        Deprecated. 
        Renames Path src to Path dst
        • Fails if src is a file and dst is a directory.
        • Fails if src is a directory and dst is a file.
        • Fails if the parent of dst does not exist or is a file.

        If OVERWRITE option is not passed as an argument, rename fails if the dst already exists.

        If OVERWRITE option is passed as an argument, rename overwrites the dst if it is a file or an empty directory. Rename fails if dst is a non-empty directory.

        Note that atomicity of rename is dependent on the file system implementation. Please refer to the file system documentation for details. This default implementation is non atomic.

        This method is deprecated since it is a temporary method added to support the transition from FileSystem to FileContext for user applications.

        Parameters:
        src - path to be renamed
        dst - new path after rename
        Throws:
        IOException - on failure

      • delete

        public abstract boolean delete(Path f,
        
             boolean recursive)
        
                        throws IOException
        Delete a file.
        Parameters:
        f - the path to delete.
        recursive - if path is a directory and set to true, the directory is deleted else throws an exception. In case of a file the recursive can be set to either true or false.
        Returns:
        true if delete is successful else false.
        Throws:
        IOException

      • deleteOnExit

        public boolean deleteOnExit(Path f)
        
                     throws IOException
        Mark a path to be deleted when FileSystem is closed. When the JVM shuts down, all FileSystem objects will be closed automatically. Then, the marked path will be deleted as a result of closing the FileSystem. The path has to exist in the file system.
        Parameters:
        f - the path to delete.
        Returns:
        true if deleteOnExit is successful, otherwise false.
        Throws:
        IOException

      • cancelDeleteOnExit

        public boolean cancelDeleteOnExit(Path f)
        Cancel the deletion of the path when the FileSystem is closed
        Parameters:
        f - the path to cancel deletion

      • processDeleteOnExit

        protected void processDeleteOnExit()
        Delete all files that were marked as delete-on-exit. This recursively deletes all files in the specified paths.

      • isDirectory

        public boolean isDirectory(Path f)
        
                    throws IOException
        True iff the named path is a directory. Note: Avoid using this method. Instead reuse the FileStatus returned by getFileStatus() or listStatus() methods.
        Parameters:
        f - path to check
        Throws:
        IOException

      • isFile

        public boolean isFile(Path f)
        
               throws IOException
        True iff the named path is a regular file. Note: Avoid using this method. Instead reuse the FileStatus returned by getFileStatus() or listStatus() methods.
        Parameters:
        f - path to check
        Throws:
        IOException

      • listCorruptFileBlocks

        public org.apache.hadoop.fs.RemoteIterator<Path> listCorruptFileBlocks(Path path)
        
                                                                throws IOException
        Returns:
        an iterator over the corrupt files under the given path (may contain duplicates if a file has more than one corrupt block)
        Throws:
        IOException

      • listStatus

        public FileStatus[] listStatus(Path[] files)
        
                        throws FileNotFoundException,
        IOException
        Filter files/directories in the given list of paths using default path filter.
        Parameters:
        files - a list of paths
        Returns:
        a list of statuses for the files under the given paths after applying the filter default Path filter
        Throws:
        FileNotFoundException - when the path does not exist; IOException see specific implementation
        IOException

      • globStatus

        public FileStatus[] globStatus(Path pathPattern)
        
                        throws IOException

        Return all the files that match filePattern and are not checksum files. Results are sorted by their names.

        A filename pattern is composed of regular characters and special pattern matching characters, which are:

        ?
        Matches any single character.
        *
        Matches zero or more characters.
        [abc]
        Matches a single character from character set {a,b,c}.
        [a-b]
        Matches a single character from the character range {a...b}. Note that character a must be lexicographically less than or equal to character b.
        [^a]
        Matches a single character that is not from character set or range {a}. Note that the ^ character must occur immediately to the right of the opening bracket.
        \c
        Removes (escapes) any special meaning of character c.
        {ab,cd}
        Matches a string from the string set {ab, cd}
        {ab,c{de,fh}}
        Matches a string from the string set {ab, cde, cfh}
        Parameters:
        pathPattern - a regular expression specifying a pth pattern
        Returns:
        an array of paths that match the path pattern
        Throws:
        IOException

      • globStatus

        public FileStatus[] globStatus(Path pathPattern,
        PathFilter filter)
        
                        throws IOException
        Return an array of FileStatus objects whose path names match pathPattern and is accepted by the user-supplied path filter. Results are sorted by their path names. Return null if pathPattern has no glob and the path does not exist. Return an empty array if pathPattern has a glob and no path matches it.
        Parameters:
        pathPattern - a regular expression specifying the path pattern
        filter - a user-supplied path filter
        Returns:
        an array of FileStatus objects
        Throws:
        IOException - if any I/O error occurs when fetching file status

      • listLocatedStatus

        public org.apache.hadoop.fs.RemoteIterator<LocatedFileStatus> listLocatedStatus(Path f)
        
                                                                         throws FileNotFoundException,
        IOException
        List the statuses of the files/directories in the given path if the path is a directory. Return the file's status and block locations If the path is a file. If a returned status is a file, it contains the file's block locations.
        Parameters:
        f - is the path
        Returns:
        an iterator that traverses statuses of the files/directories in the given path
        Throws:
        FileNotFoundException - If f does not exist
        IOException - If an I/O error occurred

      • listFiles

        public org.apache.hadoop.fs.RemoteIterator<LocatedFileStatus> listFiles(Path f,
        
                                                               boolean recursive)
        
                                                                 throws FileNotFoundException,
        IOException
        List the statuses and block locations of the files in the given path. If the path is a directory, if recursive is false, returns files in the directory; if recursive is true, return files in the subtree rooted at the path. If the path is a file, return the file's status and block locations.
        Parameters:
        f - is the path
        recursive - if the subdirectories need to be traversed recursively
        Returns:
        an iterator that traverses statuses of the files
        Throws:
        FileNotFoundException - when the path does not exist; IOException see specific implementation
        IOException

      • getHomeDirectory

        public Path getHomeDirectory()
        Return the current user's home directory in this filesystem. The default implementation returns "/user/$USER/".

      • setWorkingDirectory

        public abstract void setWorkingDirectory(Path new_dir)
        Set the current working directory for the given file system. All relative paths will be resolved relative to it.
        Parameters:
        new_dir -

      • getWorkingDirectory

        public abstract Path getWorkingDirectory()
        Get the current working directory for the given file system
        Returns:
        the directory pathname

      • getInitialWorkingDirectory

        protected Path getInitialWorkingDirectory()
        Note: with the new FilesContext class, getWorkingDirectory() will be removed. The working directory is implemented in FilesContext. Some file systems like LocalFileSystem have an initial workingDir that we use as the starting workingDir. For other file systems like HDFS there is no built in notion of an initial workingDir.
        Returns:
        if there is built in notion of workingDir then it is returned; else a null is returned.

      • mkdirs

        public abstract boolean mkdirs(Path f,
        FsPermission permission)
        
                        throws IOException
        Make the given file and all non-existent parents into directories. Has the semantics of Unix 'mkdir -p'. Existence of the directory hierarchy is not an error.
        Parameters:
        f - path to create
        permission - to apply to f
        Throws:
        IOException

      • copyFromLocalFile

        public void copyFromLocalFile(Path src,
        Path dst)
        
                       throws IOException
        The src file is on the local disk. Add it to FS at the given dst name and the source is kept intact afterwards
        Parameters:
        src - path
        dst - path
        Throws:
        IOException

      • moveFromLocalFile

        public void moveFromLocalFile(Path[] srcs,
        Path dst)
        
                       throws IOException
        The src files is on the local disk. Add it to FS at the given dst name, removing the source afterwards.
        Parameters:
        srcs - path
        dst - path
        Throws:
        IOException

      • moveFromLocalFile

        public void moveFromLocalFile(Path src,
        Path dst)
        
                       throws IOException
        The src file is on the local disk. Add it to FS at the given dst name, removing the source afterwards.
        Parameters:
        src - path
        dst - path
        Throws:
        IOException

      • copyFromLocalFile

        public void copyFromLocalFile(boolean delSrc,
        Path src,
        Path dst)
        
                       throws IOException
        The src file is on the local disk. Add it to FS at the given dst name. delSrc indicates if the source should be removed
        Parameters:
        delSrc - whether to delete the src
        src - path
        dst - path
        Throws:
        IOException

      • copyFromLocalFile

        public void copyFromLocalFile(boolean delSrc,
        
                     boolean overwrite,
        Path[] srcs,
        Path dst)
        
                       throws IOException
        The src files are on the local disk. Add it to FS at the given dst name. delSrc indicates if the source should be removed
        Parameters:
        delSrc - whether to delete the src
        overwrite - whether to overwrite an existing file
        srcs - array of paths which are source
        dst - path
        Throws:
        IOException

      • copyFromLocalFile

        public void copyFromLocalFile(boolean delSrc,
        
                     boolean overwrite,
        Path src,
        Path dst)
        
                       throws IOException
        The src file is on the local disk. Add it to FS at the given dst name. delSrc indicates if the source should be removed
        Parameters:
        delSrc - whether to delete the src
        overwrite - whether to overwrite an existing file
        src - path
        dst - path
        Throws:
        IOException

      • copyToLocalFile

        public void copyToLocalFile(Path src,
        Path dst)
        
                     throws IOException
        The src file is under FS, and the dst is on the local disk. Copy it from FS control to the local dst name.
        Parameters:
        src - path
        dst - path
        Throws:
        IOException

      • moveToLocalFile

        public void moveToLocalFile(Path src,
        Path dst)
        
                     throws IOException
        The src file is under FS, and the dst is on the local disk. Copy it from FS control to the local dst name. Remove the source afterwards
        Parameters:
        src - path
        dst - path
        Throws:
        IOException

      • copyToLocalFile

        public void copyToLocalFile(boolean delSrc,
        Path src,
        Path dst)
        
                     throws IOException
        The src file is under FS, and the dst is on the local disk. Copy it from FS control to the local dst name. delSrc indicates if the src will be removed or not.
        Parameters:
        delSrc - whether to delete the src
        src - path
        dst - path
        Throws:
        IOException

      • copyToLocalFile

        public void copyToLocalFile(boolean delSrc,
        Path src,
        Path dst,
        
                   boolean useRawLocalFileSystem)
        
                     throws IOException
        The src file is under FS, and the dst is on the local disk. Copy it from FS control to the local dst name. delSrc indicates if the src will be removed or not. useRawLocalFileSystem indicates whether to use RawLocalFileSystem as local file system or not. RawLocalFileSystem is non crc file system.So, It will not create any crc files at local.
        Parameters:
        delSrc - whether to delete the src
        src - path
        dst - path
        useRawLocalFileSystem - whether to use RawLocalFileSystem as local file system or not.
        Throws:
        IOException - - if any IO error

      • startLocalOutput

        public Path startLocalOutput(Path fsOutputFile,
        Path tmpLocalFile)
        
                      throws IOException
        Returns a local File that the user can write output to. The caller provides both the eventual FS target name and the local working file. If the FS is local, we write directly into the target. If the FS is remote, we write into the tmp local area.
        Parameters:
        fsOutputFile - path of output file
        tmpLocalFile - path of local tmp file
        Throws:
        IOException

      • completeLocalOutput

        public void completeLocalOutput(Path fsOutputFile,
        Path tmpLocalFile)
        
                         throws IOException
        Called when we're all done writing to the target. A local FS will do nothing, because we've written to exactly the right place. A remote FS will copy the contents of tmpLocalFile to the correct target at fsOutputFile.
        Parameters:
        fsOutputFile - path of output file
        tmpLocalFile - path to local tmp file
        Throws:
        IOException

      • getDefaultBlockSize

        public long getDefaultBlockSize(Path f)
        Return the number of bytes that large input files should be optimally be split into to minimize i/o time. The given path will be used to locate the actual filesystem. The full path does not have to exist.
        Parameters:
        f - path of file
        Returns:
        the default block size for the path's filesystem

      • getDefaultReplication

        public short getDefaultReplication(Path path)
        Get the default replication for a path. The given path will be used to locate the actual filesystem. The full path does not have to exist.
        Parameters:
        path - of the file
        Returns:
        default replication for the path's filesystem

      • getFileChecksum

        public FileChecksum getFileChecksum(Path f)
        
                             throws IOException
        Get the checksum of a file.
        Parameters:
        f - The file path
        Returns:
        The file checksum. The default return value is null, which indicates that no checksum algorithm is implemented in the corresponding FileSystem.
        Throws:
        IOException

      • setVerifyChecksum

        public void setVerifyChecksum(boolean verifyChecksum)
        Set the verify checksum flag. This is only applicable if the corresponding FileSystem supports checksum. By default doesn't do anything.
        Parameters:
        verifyChecksum -

      • setWriteChecksum

        public void setWriteChecksum(boolean writeChecksum)
        Set the write checksum flag. This is only applicable if the corresponding FileSystem supports checksum. By default doesn't do anything.
        Parameters:
        writeChecksum -

      • getStatus

        public FsStatus getStatus()
        
                   throws IOException
        Returns a status object describing the use and capacity of the file system. If the file system has multiple partitions, the use and capacity of the root partition is reflected.
        Returns:
        a FsStatus object
        Throws:
        IOException - see specific implementation

      • getStatus

        public FsStatus getStatus(Path p)
        
                   throws IOException
        Returns a status object describing the use and capacity of the file system. If the file system has multiple partitions, the use and capacity of the partition pointed to by the specified path is reflected.
        Parameters:
        p - Path for which status should be obtained. null means the default partition.
        Returns:
        a FsStatus object
        Throws:
        IOException - see specific implementation

      • setOwner

        public void setOwner(Path p,
        String username,
        String groupname)
        
              throws IOException
        Set owner of a path (i.e. a file or a directory). The parameters username and groupname cannot both be null.
        Parameters:
        p - The path
        username - If it is null, the original username remains unchanged.
        groupname - If it is null, the original groupname remains unchanged.
        Throws:
        IOException

      • setTimes

        public void setTimes(Path p,
        
            long mtime,
        
            long atime)
        
              throws IOException
        Set access time of a file
        Parameters:
        p - The path
        mtime - Set the modification time of this file. The number of milliseconds since Jan 1, 1970. A value of -1 means that this call should not set modification time.
        atime - Set the access time of this file. The number of milliseconds since Jan 1, 1970. A value of -1 means that this call should not set access time.
        Throws:
        IOException

      • getStatistics

        @Deprecated
        
public static Map<String,org.apache.hadoop.fs.FileSystem.Statistics> getStatistics()
        Deprecated. use getAllStatistics() instead
        Get the Map of Statistics object indexed by URI Scheme.
        Returns:
        a Map having a key as URI scheme and value as Statistics object

      • getAllStatistics

        public static List<org.apache.hadoop.fs.FileSystem.Statistics> getAllStatistics()
        Return the FileSystem classes that have Statistics

      • getStatistics

        public static org.apache.hadoop.fs.FileSystem.Statistics getStatistics(String scheme,
        Class<? extends FileSystem> cls)
        Get the statistics for a particular file system
        Parameters:
        cls - the class to lookup
        Returns:
        a statistics object

      • clearStatistics

        public static void clearStatistics()
        Reset all statistics for all file systems

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