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java.lang.Object
|
+----java.io.File
The File class is intended to provide an abstraction
that deals with most of the machine dependent complexities of
files and pathnames in a machine-independent fashion.
Note that whenever a filename or path is used it is assumed that the host's file naming conventions are used.
pathSeparator
pathSeparatorChar
separator
separatorChar
File(File, String)
File instance that represents the file
with the specified name in the specified directory.
File(String)
File instance that represents the file
whose pathname is the given path argument.
File(String, String)
File instance whose pathname is the
pathname of the specified directory, followed by the separator
character, followed by the name argument.
canRead()
canWrite()
compareTo(File)
compareTo(Object)
createTempFile(String)
createTempFile(String, File)
Creates an empty temporary file in the specified directory after a specified pattern.
delete()
deleteOnExit()
equals(Object)
exists()
File exists.
getAbsolutePath()
getCanonicalPath()
File object's pathname.
getName()
getParent()
File
object, or null if the name has no parent part.
getPath()
hashCode()
isAbsolute()
File object is an
absolute pathname.
isDirectory()
File
object is a directory.
isFile()
File
object is a "normal" file.
lastModified()
File object was last modified.
length()
File object.
list()
File object.
list(FilenameFilter)
File that satisfy the specified filter.
mkdir()
File object.
mkdirs()
File object, including any necessary parent directories.
renameTo(File)
File object to
have the pathname given by the File argument.
toString()
separator
public static final String separator
file.separator.
separatorChar
public static final char separatorChar
file.separator. This character
separates the directory and file components in a filename.
pathSeparator
public static final String pathSeparator
path.separator.
pathSeparatorChar
public static final char pathSeparatorChar
path.separator. This character is
often used to separate filenames in a sequence of files given as a
"path list".
File
public File(String path)
File instance that represents the file
whose pathname is the given path argument.
null.
File
public File(String path,
String name)
File instance whose pathname is the
pathname of the specified directory, followed by the separator
character, followed by the name argument.
File
public File(File dir,
String name)
File instance that represents the file
with the specified name in the specified directory.
If the directory argument is null, the resulting
File instance represents a file in the
(system-dependent) current directory whose pathname is the
name argument. Otherwise, the File
instance represents a file whose pathname is the pathname of the
directory, followed by the separator character, followed by the
name argument.
getName
public String getName()
File object.
getPath
public String getPath()
File object.
getAbsolutePath
public String getAbsolutePath()
The system property user.dir contains the current
user directory.
File.
getCanonicalPath
public String getCanonicalPath() throws IOException
File object's pathname.
The precise definition of canonical form is system-dependent, but it
usually specifies an absolute pathname in which all relative references
and references to the current user directory have been completely
resolved. The canonical form of a pathname of a nonexistent file may
not be defined.
getParent
public String getParent()
File
object, or null if the name has no parent part. The parent
part is generally everything leading up to the last occurrence of the
separator character, although the precise definition is system
dependent. On UNIX, for example, the parent part of
"/usr/lib" is "/usr", whose parent part is
"/", which in turn has no parent. On Windows platforms,
the parent part of "c:\java" is "c:\", which
in turn has no parent.
createTempFile
public static File createTempFile(String pattern,
File directory) throws IOException
Creates an empty temporary file in the specified directory after a specified pattern.
Temporary files are created in the specified directory. If the specified directory is null, the default temporary directory is used. The default temporary directory may be specified using the java.tmpdir property. If it is not explicitely specified, it is defaulted to the underlying platform's temporary directory (such as /tmp or /var/tmp on UNIX and c:\temp on Windows).
checkWrite method is called with the result argument
to see if the application is allowed read access to the file.
createTempFile
public static File createTempFile(String prefix) throws IOException
This call is equivalent to calling
createTempFile(String, String) with a null
argument for the directory.
deleteOnExit
public void deleteOnExit()
Once deletion has been requested, it is not possible to cancel the request. This method should therefore be used carefully.
checkDelete method is called with the pathname of
this File to see if the application is allowed to
delete the file.
exists
public boolean exists()
File exists.
true if the file specified by this object
exists; false otherwise.checkRead method is called with the pathname
of this File to see if the application is
allowed read access to the file.
canWrite
public boolean canWrite()
true if the application is allowed to write to
a file whose name is specified by this object;
false otherwise.checkWrite method is called with the pathname
of this File to see if the application is
allowed write access to the file.
canRead
public boolean canRead()
true if the file specified by this object exists
and the application can read the file;
false otherwise.checkRead method is called with the pathname
of this File to see if the application is
allowed read access to the file.
isFile
public boolean isFile()
File
object is a "normal" file.
A file is "normal" if it is not a directory and, in addition, satisfies other system-dependent criteria. Any non-directory file created by a Java application is guaranteed to be a normal file.
true if the file specified by this object
exists and is a "normal" file; false otherwise.checkRead method is called with the pathname
of this File to see if the application is
allowed read access to the file.
isDirectory
public boolean isDirectory()
File
object is a directory.
true if this File exists and is a
directory; false otherwise.checkRead method is called with the pathname
of this File to see if the application is
allowed read access to the file.
isAbsolute
public boolean isAbsolute()
File object is an
absolute pathname. The definition of an absolute pathname is system
dependent. For example, on UNIX, a pathname is absolute if its
first character is the separator character. On Windows platforms,
a pathname is absolute if its first character is an ASCII '\' or
'/', or if it begins with a letter followed by a colon.
true if the pathname indicated by the
File object is an absolute pathname;
false otherwise.
lastModified
public long lastModified()
File object was last modified.
The return value is system dependent and should only be used to compare with other values returned by last modified. It should not be interpreted as an absolute time.
0L if the specified file does not exist.checkRead method is called with the pathname
of this File to see if the application is
allowed read access to the file.
length
public long length()
File object.
0L if the specified file does not exist.checkRead method is called with the pathname
of this File to see if the application is
allowed read access to the file.
mkdir
public boolean mkdir()
File object.
true if the directory could be created;
false otherwise.checkWrite method is called with the pathname
of this File to see if the application is
allowed write access to the file.
renameTo
public boolean renameTo(File dest)
File object to
have the pathname given by the File argument.
true if the renaming succeeds;
false otherwise.checkWrite method is called both with the
pathname of this file object and with the pathname of the
destination target object to see if the application is
allowed to write to both files.
mkdirs
public boolean mkdirs()
File object, including any necessary parent directories.
true if the directory (or directories) could be
created; false otherwise.checkWrite method is called with the pathname
of each of the directories that is to be created, before
any of the directories are created.
list
public String[] list()
File object.
." and ".."
on Unix systems).checkRead method is called with the pathname
of this File to see if the application is
allowed read access to the file.
list
public String[] list(FilenameFilter filter)
File that satisfy the specified filter.
." and ".."
on Unix systems).checkRead method is called with the pathname
of this File to see if the application is
allowed read access to the file.
delete
public boolean delete()
true if the file is successfully deleted;
false otherwise.checkDelete method is called with the
pathname of this File to see if the
application is allowed to delete the file.
hashCode
public int hashCode()
File object.
equals
public boolean equals(Object obj)
true if and only if the argument is
not null and is a File object whose
pathname is equal to the pathname of this object.
true if the objects are the same;
false otherwise.
compareTo
public int compareTo(File file)
File to be compared.
0 if the argument File's pathname
is equal to this File's; a value less than 0 if
this File's pathname is lexicographically less than the File
argument's; and a value greater than 0 if this
File's pathname is lexicographically greater than the File
argument's.
compareTo
public int compareTo(Object o)
compareTo(File). Otherwise, it
throws a ClassCastException (as Files are
comparable only to other Files).
Object to be compared.
0 if the argument is a File whose
pathname is equal to this File's; a value less than
0 if the argument is a File whose pathname
is lexicographically greater than this File's; and a value
greater than 0 if the argument is a File
whosse pathname is lexicographically less than this File's.ClassCastExceptionFile.
toString
public String toString()
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