java.lang.Object
- org.apache.myfaces.util.lang.FilenameUtils

```
public class FilenameUtils
extends Object
```
General filename and filepath manipulation utilities.
When dealing with filenames you can hit problems when moving from a Windows based development machine to a Unix based production machine. This class aims to help avoid those problems.
NOTE: You may be able to avoid using this class entirely simply by using JDK File objects and the two argument constructor File(File,String).
Most methods on this class are designed to work the same on both Unix and Windows. Those that don't include 'System', 'Unix' or 'Windows' in their name.
Most methods recognise both separators (forward and back), and both sets of prefixes. See the javadoc of each method for details.
This class defines six components within a filename (example C:\dev\project\file.txt):
- the prefix - C:\
- the path - dev\project\
- the full path - C:\dev\project\
- the name - file.txt
- the base name - file
- the extension - txt
Note that this class works best if directory filenames end with a separator. If you omit the last separator, it is impossible to determine if the filename corresponds to a file or a directory. As a result, we have chosen to say it corresponds to a file.
This class only supports Unix and Windows style names. Prefixes are matched as follows:
```
 Windows:
 a\b\c.txt           --> ""          --> relative
 \a\b\c.txt          --> "\"         --> current drive absolute
 C:a\b\c.txt         --> "C:"        --> drive relative
 C:\a\b\c.txt        --> "C:\"       --> absolute
 \\server\a\b\c.txt  --> "\\server\" --> UNC

 Unix:
 a/b/c.txt           --> ""          --> relative
 /a/b/c.txt          --> "/"         --> absolute
 ~/a/b/c.txt         --> "~/"        --> current user
 ~                   --> "~/"        --> current user (slash added)
 ~user/a/b/c.txt     --> "~user/"    --> named user
 ~user               --> "~user/"    --> named user (slash added)
 
```
Both prefix styles are matched always, irrespective of the machine that you are currently running on.
Origin of code: Excalibur, Alexandria, Tomcat, Commons-Utils. NOTE: Taken from Commons-IO package
Since:

1.1

Version:

$Id$

Field Summary

Fields
Modifier and Type Field Description

static char EXTENSION_SEPARATOR
The extension separator character.

static String EXTENSION_SEPARATOR_STR
The extension separator String.

Constructor Summary

Constructors
Constructor Description

FilenameUtils()
Instances should NOT be constructed in standard programming.

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method	Description
`static String`	`concat(String basePath, String fullFilenameToAdd)`	Concatenates a filename to a base path using normal command line style rules.
`static String`	`getBaseName(String filename)`	Gets the base name, minus the full path and extension, from a full filename.
`static String`	`getExtension(String filename)`	Gets the extension of a filename.
`static String`	`getFullPath(String filename)`	Gets the full path from a full filename, which is the prefix + path.
`static String`	`getFullPathNoEndSeparator(String filename)`	Gets the full path from a full filename, which is the prefix + path, and also excluding the final directory separator.
`static String`	`getName(String filename)`	Gets the name minus the path from a full filename.
`static String`	`getPath(String filename)`	Gets the path from a full filename, which excludes the prefix.
`static String`	`getPathNoEndSeparator(String filename)`	Gets the path from a full filename, which excludes the prefix, and also excluding the final directory separator.
`static String`	`getPrefix(String filename)`	Gets the prefix from a full filename, such as `C:/` or `~/`.
`static int`	`getPrefixLength(String filename)`	Returns the length of the filename prefix, such as `C:/` or `~/`.
`static int`	`indexOfExtension(String filename)`	Returns the index of the last extension separator character, which is a dot.
`static int`	`indexOfLastSeparator(String filename)`	Returns the index of the last directory separator character.
`static String`	`normalize(String filename)`	Normalizes a path, removing double and single dot path steps.
`static String`	`normalize(String filename, boolean unixSeparator)`	Normalizes a path, removing double and single dot path steps.
`static String`	`normalizeNoEndSeparator(String filename)`	Normalizes a path, removing double and single dot path steps, and removing any final directory separator.
`static String`	`normalizeNoEndSeparator(String filename, boolean unixSeparator)`	Normalizes a path, removing double and single dot path steps, and removing any final directory separator.
`static String`	`removeExtension(String filename)`	Removes the extension from a filename.
`static String`	`separatorsToSystem(String path)`	Converts all separators to the system separator.
`static String`	`separatorsToUnix(String path)`	Converts all separators to the Unix separator of forward slash.
`static String`	`separatorsToWindows(String path)`	Converts all separators to the Windows separator of backslash.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - EXTENSION_SEPARATOR
```
public static final char EXTENSION_SEPARATOR
```
    The extension separator character.
    
    Since:
    
    1.4
    
    See Also:
    
    Constant Field Values
  - EXTENSION_SEPARATOR_STR
```
public static final String EXTENSION_SEPARATOR_STR
```
    The extension separator String.
    
    Since:
    
    1.4
- Constructor Detail
  - FilenameUtils
```
public FilenameUtils()
```
    Instances should NOT be constructed in standard programming.
- Method Detail
  - normalize
```
public static String normalize(String filename)
```
    Normalizes a path, removing double and single dot path steps.
    This method normalizes a path to a standard format. The input may contain separators in either Unix or Windows format. The output will contain separators in the format of the system.
    A trailing slash will be retained. A double slash will be merged to a single slash (but UNC names are handled). A single dot path segment will be removed. A double dot will cause that path segment and the one before to be removed. If the double dot has no parent path segment to work with, null is returned.
    The output will be the same on both Unix and Windows except for the separator character.
    /foo// --> /foo/ /foo/./ --> /foo/ /foo/../bar --> /bar /foo/../bar/ --> /bar/ /foo/../bar/../baz --> /baz //foo//./bar --> /foo/bar /../ --> null ../foo --> null foo/bar/.. --> foo/ foo/../../bar --> null foo/../bar --> bar //server/foo/../bar --> //server/bar //server/../bar --> null C:\foo\..\bar --> C:\bar C:\..\bar --> null ~/foo/../bar/ --> ~/bar/ ~/../bar --> null
    (Note the file separator returned will be correct for Windows/Unix)
    Parameters:
    
    filename - the filename to normalize, null returns null
    
    Returns:
    
    the normalized filename, or null if invalid
  - normalize
```
public static String normalize(String filename,
                               boolean unixSeparator)
```
    Normalizes a path, removing double and single dot path steps.
    This method normalizes a path to a standard format. The input may contain separators in either Unix or Windows format. The output will contain separators in the format specified.
    A trailing slash will be retained. A double slash will be merged to a single slash (but UNC names are handled). A single dot path segment will be removed. A double dot will cause that path segment and the one before to be removed. If the double dot has no parent path segment to work with, null is returned.
    The output will be the same on both Unix and Windows except for the separator character.
    /foo// --> /foo/ /foo/./ --> /foo/ /foo/../bar --> /bar /foo/../bar/ --> /bar/ /foo/../bar/../baz --> /baz //foo//./bar --> /foo/bar /../ --> null ../foo --> null foo/bar/.. --> foo/ foo/../../bar --> null foo/../bar --> bar //server/foo/../bar --> //server/bar //server/../bar --> null C:\foo\..\bar --> C:\bar C:\..\bar --> null ~/foo/../bar/ --> ~/bar/ ~/../bar --> null
    The output will be the same on both Unix and Windows including the separator character.
    Parameters:
    
    filename - the filename to normalize, null returns null
    
    unixSeparator - true if a unix separator should be used or false if a windows separator should be used.
    
    Returns:
    
    the normalized filename, or null if invalid
    
    Since:
    
    2.0
  - normalizeNoEndSeparator
```
public static String normalizeNoEndSeparator(String filename)
```
    Normalizes a path, removing double and single dot path steps, and removing any final directory separator.
    This method normalizes a path to a standard format. The input may contain separators in either Unix or Windows format. The output will contain separators in the format of the system.
    A trailing slash will be removed. A double slash will be merged to a single slash (but UNC names are handled). A single dot path segment will be removed. A double dot will cause that path segment and the one before to be removed. If the double dot has no parent path segment to work with, null is returned.
    The output will be the same on both Unix and Windows except for the separator character.
    /foo// --> /foo /foo/./ --> /foo /foo/../bar --> /bar /foo/../bar/ --> /bar /foo/../bar/../baz --> /baz //foo//./bar --> /foo/bar /../ --> null ../foo --> null foo/bar/.. --> foo foo/../../bar --> null foo/../bar --> bar //server/foo/../bar --> //server/bar //server/../bar --> null C:\foo\..\bar --> C:\bar C:\..\bar --> null ~/foo/../bar/ --> ~/bar ~/../bar --> null
    (Note the file separator returned will be correct for Windows/Unix)
    Parameters:
    
    filename - the filename to normalize, null returns null
    
    Returns:
    
    the normalized filename, or null if invalid
  - normalizeNoEndSeparator
```
public static String normalizeNoEndSeparator(String filename,
                                             boolean unixSeparator)
```
    Normalizes a path, removing double and single dot path steps, and removing any final directory separator.
    This method normalizes a path to a standard format. The input may contain separators in either Unix or Windows format. The output will contain separators in the format specified.
    A trailing slash will be removed. A double slash will be merged to a single slash (but UNC names are handled). A single dot path segment will be removed. A double dot will cause that path segment and the one before to be removed. If the double dot has no parent path segment to work with, null is returned.
    The output will be the same on both Unix and Windows including the separator character.
    /foo// --> /foo /foo/./ --> /foo /foo/../bar --> /bar /foo/../bar/ --> /bar /foo/../bar/../baz --> /baz //foo//./bar --> /foo/bar /../ --> null ../foo --> null foo/bar/.. --> foo foo/../../bar --> null foo/../bar --> bar //server/foo/../bar --> //server/bar //server/../bar --> null C:\foo\..\bar --> C:\bar C:\..\bar --> null ~/foo/../bar/ --> ~/bar ~/../bar --> null
    Parameters:
    
    filename - the filename to normalize, null returns null
    
    unixSeparator - true if a unix separator should be used or false if a windows separtor should be used.
    
    Returns:
    
    the normalized filename, or null if invalid
    
    Since:
    
    2.0
  - concat
```
public static String concat(String basePath,
                            String fullFilenameToAdd)
```
    Concatenates a filename to a base path using normal command line style rules.
    The effect is equivalent to resultant directory after changing directory to the first argument, followed by changing directory to the second argument.
    The first argument is the base path, the second is the path to concatenate. The returned path is always normalized via normalize(String), thus .. is handled.
    If pathToAdd is absolute (has an absolute prefix), then it will be normalized and returned. Otherwise, the paths will be joined, normalized and returned.
    The output will be the same on both Unix and Windows except for the separator character.
    /foo/ + bar --> /foo/bar /foo + bar --> /foo/bar /foo + /bar --> /bar /foo + C:/bar --> C:/bar /foo + C:bar --> C:bar (*) /foo/a/ + ../bar --> foo/bar /foo/ + ../../bar --> null /foo/ + /bar --> /bar /foo/.. + /bar --> /bar /foo + bar/c.txt --> /foo/bar/c.txt /foo/c.txt + bar --> /foo/c.txt/bar (!)
    (*) Note that the Windows relative drive prefix is unreliable when used with this method. (!) Note that the first parameter must be a path. If it ends with a name, then the name will be built into the concatenated path. If this might be a problem, use getFullPath(String) on the base path argument.
    Parameters:
    
    basePath - the base path to attach to, always treated as a path
    
    fullFilenameToAdd - the filename (or path) to attach to the base
    
    Returns:
    
    the concatenated path, or null if invalid
  - separatorsToUnix
```
public static String separatorsToUnix(String path)
```
    Converts all separators to the Unix separator of forward slash.
    
    Parameters:
    
    path - the path to be changed, null ignored
    
    Returns:
    
    the updated path
  - separatorsToWindows
```
public static String separatorsToWindows(String path)
```
    Converts all separators to the Windows separator of backslash.
    
    Parameters:
    
    path - the path to be changed, null ignored
    
    Returns:
    
    the updated path
  - separatorsToSystem
```
public static String separatorsToSystem(String path)
```
    Converts all separators to the system separator.
    
    Parameters:
    
    path - the path to be changed, null ignored
    
    Returns:
    
    the updated path
  - getPrefixLength
```
public static int getPrefixLength(String filename)
```
    Returns the length of the filename prefix, such as C:/ or ~/.
    This method will handle a file in either Unix or Windows format.
    The prefix length includes the first slash in the full filename if applicable. Thus, it is possible that the length returned is greater than the length of the input string.
    Windows: a\b\c.txt --> "" --> relative \a\b\c.txt --> "\" --> current drive absolute C:a\b\c.txt --> "C:" --> drive relative C:\a\b\c.txt --> "C:\" --> absolute \\server\a\b\c.txt --> "\\server\" --> UNC \\\a\b\c.txt --> error, length = -1 Unix: a/b/c.txt --> "" --> relative /a/b/c.txt --> "/" --> absolute ~/a/b/c.txt --> "~/" --> current user ~ --> "~/" --> current user (slash added) ~user/a/b/c.txt --> "~user/" --> named user ~user --> "~user/" --> named user (slash added) //server/a/b/c.txt --> "//server/" ///a/b/c.txt --> error, length = -1
    
    The output will be the same irrespective of the machine that the code is running on. ie. both Unix and Windows prefixes are matched regardless. Note that a leading // (or \\) is used to indicate a UNC name on Windows. These must be followed by a server name, so double-slashes are not collapsed to a single slash at the start of the filename.
    Parameters:
    
    filename - the filename to find the prefix in, null returns -1
    
    Returns:
    
    the length of the prefix, -1 if invalid or null
  - indexOfLastSeparator
```
public static int indexOfLastSeparator(String filename)
```
    Returns the index of the last directory separator character.
    This method will handle a file in either Unix or Windows format. The position of the last forward or backslash is returned.
    The output will be the same irrespective of the machine that the code is running on.
    
    Parameters:
    
    filename - the filename to find the last path separator in, null returns -1
    
    Returns:
    
    the index of the last separator character, or -1 if there is no such character
  - indexOfExtension
```
public static int indexOfExtension(String filename)
```
    Returns the index of the last extension separator character, which is a dot.
    This method also checks that there is no directory separator after the last dot. To do this it uses indexOfLastSeparator(String) which will handle a file in either Unix or Windows format.
    The output will be the same irrespective of the machine that the code is running on.
    
    Parameters:
    
    filename - the filename to find the last path separator in, null returns -1
    
    Returns:
    
    the index of the last separator character, or -1 if there is no such character
  - getPrefix
```
public static String getPrefix(String filename)
```
    Gets the prefix from a full filename, such as C:/ or ~/.
    This method will handle a file in either Unix or Windows format. The prefix includes the first slash in the full filename where applicable.
    Windows: a\b\c.txt --> "" --> relative \a\b\c.txt --> "\" --> current drive absolute C:a\b\c.txt --> "C:" --> drive relative C:\a\b\c.txt --> "C:\" --> absolute \\server\a\b\c.txt --> "\\server\" --> UNC Unix: a/b/c.txt --> "" --> relative /a/b/c.txt --> "/" --> absolute ~/a/b/c.txt --> "~/" --> current user ~ --> "~/" --> current user (slash added) ~user/a/b/c.txt --> "~user/" --> named user ~user --> "~user/" --> named user (slash added)
    
    The output will be the same irrespective of the machine that the code is running on. ie. both Unix and Windows prefixes are matched regardless.
    Parameters:
    
    filename - the filename to query, null returns null
    
    Returns:
    
    the prefix of the file, null if invalid
  - getPath
```
public static String getPath(String filename)
```
    Gets the path from a full filename, which excludes the prefix.
    This method will handle a file in either Unix or Windows format. The method is entirely text based, and returns the text before and including the last forward or backslash.
    C:\a\b\c.txt --> a\b\ ~/a/b/c.txt --> a/b/ a.txt --> "" a/b/c --> a/b/ a/b/c/ --> a/b/c/
    
    The output will be the same irrespective of the machine that the code is running on.
    This method drops the prefix from the result. See getFullPath(String) for the method that retains the prefix.
    Parameters:
    
    filename - the filename to query, null returns null
    
    Returns:
    
    the path of the file, an empty string if none exists, null if invalid
  - getPathNoEndSeparator
```
public static String getPathNoEndSeparator(String filename)
```
    Gets the path from a full filename, which excludes the prefix, and also excluding the final directory separator.
    This method will handle a file in either Unix or Windows format. The method is entirely text based, and returns the text before the last forward or backslash.
    C:\a\b\c.txt --> a\b ~/a/b/c.txt --> a/b a.txt --> "" a/b/c --> a/b a/b/c/ --> a/b/c
    
    The output will be the same irrespective of the machine that the code is running on.
    This method drops the prefix from the result. See getFullPathNoEndSeparator(String) for the method that retains the prefix.
    Parameters:
    
    filename - the filename to query, null returns null
    
    Returns:
    
    the path of the file, an empty string if none exists, null if invalid
  - getFullPath
```
public static String getFullPath(String filename)
```
    Gets the full path from a full filename, which is the prefix + path.
    This method will handle a file in either Unix or Windows format. The method is entirely text based, and returns the text before and including the last forward or backslash.
    C:\a\b\c.txt --> C:\a\b\ ~/a/b/c.txt --> ~/a/b/ a.txt --> "" a/b/c --> a/b/ a/b/c/ --> a/b/c/ C: --> C: C:\ --> C:\ ~ --> ~/ ~/ --> ~/ ~user --> ~user/ ~user/ --> ~user/
    
    The output will be the same irrespective of the machine that the code is running on.
    Parameters:
    
    filename - the filename to query, null returns null
    
    Returns:
    
    the path of the file, an empty string if none exists, null if invalid
  - getFullPathNoEndSeparator
```
public static String getFullPathNoEndSeparator(String filename)
```
    Gets the full path from a full filename, which is the prefix + path, and also excluding the final directory separator.
    This method will handle a file in either Unix or Windows format. The method is entirely text based, and returns the text before the last forward or backslash.
    C:\a\b\c.txt --> C:\a\b ~/a/b/c.txt --> ~/a/b a.txt --> "" a/b/c --> a/b a/b/c/ --> a/b/c C: --> C: C:\ --> C:\ ~ --> ~ ~/ --> ~ ~user --> ~user ~user/ --> ~user
    
    The output will be the same irrespective of the machine that the code is running on.
    Parameters:
    
    filename - the filename to query, null returns null
    
    Returns:
    
    the path of the file, an empty string if none exists, null if invalid
  - getName
```
public static String getName(String filename)
```
    Gets the name minus the path from a full filename.
    This method will handle a file in either Unix or Windows format. The text after the last forward or backslash is returned.
    a/b/c.txt --> c.txt a.txt --> a.txt a/b/c --> c a/b/c/ --> ""
    
    The output will be the same irrespective of the machine that the code is running on.
    Parameters:
    
    filename - the filename to query, null returns null
    
    Returns:
    
    the name of the file without the path, or an empty string if none exists
  - getBaseName
```
public static String getBaseName(String filename)
```
    Gets the base name, minus the full path and extension, from a full filename.
    This method will handle a file in either Unix or Windows format. The text after the last forward or backslash and before the last dot is returned.
    a/b/c.txt --> c a.txt --> a a/b/c --> c a/b/c/ --> ""
    
    The output will be the same irrespective of the machine that the code is running on.
    Parameters:
    
    filename - the filename to query, null returns null
    
    Returns:
    
    the name of the file without the path, or an empty string if none exists
  - getExtension
```
public static String getExtension(String filename)
```
    Gets the extension of a filename.
    This method returns the textual part of the filename after the last dot. There must be no directory separator after the dot.
    foo.txt --> "txt" a/b/c.jpg --> "jpg" a/b.txt/c --> "" a/b/c --> ""
    
    The output will be the same irrespective of the machine that the code is running on.
    Parameters:
    
    filename - the filename to retrieve the extension of.
    
    Returns:
    
    the extension of the file or an empty string if none exists or null if the filename is null.
  - removeExtension
```
public static String removeExtension(String filename)
```
    Removes the extension from a filename.
    This method returns the textual part of the filename before the last dot. There must be no directory separator after the dot.
    foo.txt --> foo a\b\c.jpg --> a\b\c a\b\c --> a\b\c a.b\c --> a.b\c
    
    The output will be the same irrespective of the machine that the code is running on.
    Parameters:
    
    filename - the filename to query, null returns null
    
    Returns:
    
    the filename minus the extension

Modifier and Type	Field	Description
`static char`	`EXTENSION_SEPARATOR`	The extension separator character.
`static String`	`EXTENSION_SEPARATOR_STR`	The extension separator String.

Class FilenameUtils

Field Summary

Constructor Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

EXTENSION_SEPARATOR

EXTENSION_SEPARATOR_STR

Constructor Detail

FilenameUtils

Method Detail

normalize

normalize

normalizeNoEndSeparator

normalizeNoEndSeparator

concat

separatorsToUnix

separatorsToWindows

separatorsToSystem

getPrefixLength

indexOfLastSeparator

indexOfExtension

getPrefix

getPath

getPathNoEndSeparator

getFullPath

getFullPathNoEndSeparator

getName

getBaseName

getExtension

removeExtension