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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.
File
instance that represents the file
with the specified name in the specified directory.
File
instance that represents the file
whose pathname is the given path argument.
File
instance whose pathname is the
pathname of the specified directory, followed by the separator
character, followed by the name
argument.
File
exists.
File
object's pathname.
File
object, or null
if the name has no parent part.
File
object is an
absolute pathname.
File
object is a directory.
File
object is a "normal" file.
File
object was last modified.
File
object.
File
object.
File
that satisfy the specified filter.
File
object.
File
object, including any necessary parent directories.
File
object to
have the pathname given by the File
argument.
public static final String separator
file.separator
.
public static final char separatorChar
file.separator
. This character
separates the directory and file components in a filename.
public static final String pathSeparator
path.separator
.
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".
public File(String path)
File
instance that represents the file
whose pathname is the given path argument.
null
.
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.
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.
public String getName()
File
object.
public String getPath()
File
object.
public String getAbsolutePath()
The system property user.dir
contains the current
user directory.
File
.
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.
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.
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.
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.
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.
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.
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.
public native 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.
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.
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.
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.
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.
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.
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.
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.
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.
public int hashCode()
File
object.
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.
public String toString()
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