File deals directly with files and the file system. File class describes the properties of a file or a directory itself.
A File object tells the information associated with a disk file, such as the permissions, time, date, and directory path, and to navigate subdirectory hierarchies.
A directory in Java is treated simply as a File with one additional property. A list of filenames that can be examined by the list( ) method.
File(String directoryPath)
directoryPath is the path name of the file
File(String directoryPath, String filename)
filename is the name of the file or subdirectory,
File(File dirObj, String filename)
dirObj is a File object that specifies a directory
File(URI uriObj)
uriObj is a URI object that describes a file.
File Object Description
File f1 = new File("/"); f1 is constructed with a directory path as the only argument.
File f2 = new File("/","autoexec.bat"); f2 has the path and the filename.
File f3 = new File(f1,"autoexec.bat"); f3 refers to the same file as f2.
If you use a forward slash (/) on a Windows, the path will still resolve correctly. To use a backslash character (\), you will need to use its escape sequence (\\) within a string.
Constants from File class
static String pathSeparator
The system-dependent path-separator character, represented as a string for convenience.
static char pathSeparatorChar
The system-dependent path-separator character.
static String separator
The system-dependent default name-separator character, represented as a string for convenience.
static char separatorChar
The system-dependent default name-separator character.
File Constructor
File(File parent, String child)
Creates a new File instance from a parent abstract pathname and a child pathname string.
File(String pathname)
Creates a new File instance by converting the given pathname string into an abstract pathname.
File(String parent, String child)
Creates a new File instance from a parent pathname string and a child pathname string.
File(URI uri)
Creates a new File instance by converting the given file: URI into an abstract pathname.
Is it executable, readable or writable
boolean canExecute()
Tests whether the application can execute the file denoted by this abstract pathname.
boolean canRead()
Tests whether the application can read the file denoted by this abstract pathname.
boolean canWrite()
Tests whether the application can modify the file denoted by this abstract pathname.
Compare two file path
int compareTo(File pathname)
Compares two abstract pathnames lexicographically.
boolean equals(Object obj)
Tests this abstract pathname for equality with the given object.
Create a file
boolean createNewFile()
Atomically creates a new, empty file named by this abstract pathname if and only if a file with this name does not yet exist.
static File createTempFile(String prefix, String suffix)
Creates an empty file in the default temporary-file directory, using the given prefix and suffix to generate its name.
static File createTempFile(String prefix, String suffix, File directory)
Creates a new empty file in the specified directory, using the given prefix and suffix strings to generate its name.
Delete a file
boolean delete()
Deletes the file or directory denoted by this abstract pathname.
void deleteOnExit()
Requests that the file or directory denoted by this abstract pathname be deleted when the virtual machine terminates.
Is it a file or a directory
boolean isDirectory()
Tests whether the file denoted by this abstract pathname is a directory.
boolean isFile()
returns true if called on a file and false if called on a directory.
Whether the file or directory denoted by this abstract pathname exists
boolean exists()
Tests whether the file or directory denoted by this abstract pathname exists.
Whether this abstract pathname is absolute
boolean isAbsolute()
Tests whether this abstract pathname is absolute.
Is this file hidden
boolean isHidden()
Tests whether the file named by this abstract pathname is a hidden file.
Get the file last modified time
long lastModified()
Returns the time that the file denoted by this abstract pathname was last modified.
Get the file size
long length()
Returns the length of the file denoted by this abstract pathname.
Get file path and name
File getAbsoluteFile()
Returns the absolute form of this abstract pathname.
String getAbsolutePath()
Returns the absolute pathname string of this abstract pathname.
File getCanonicalFile()
Returns the canonical form of this abstract pathname.
String getCanonicalPath()
Returns the canonical pathname string of this abstract pathname.
String getName()
Returns the name of the file or directory denoted by this abstract pathname.
String getPath()
Converts this abstract pathname into a pathname string.
Get free space, total space, usable space
long getFreeSpace()
Returns the number of unallocated bytes in the partition named by this abstract path name.
long getTotalSpace()
Returns the size of the partition named by this abstract pathname.
long getUsableSpace()
Returns the number of bytes available to this virtual machine on the partition named by this abstract pathname.
Get parent file
String getParent()
Returns the pathname string of this abstract pathname's parent, or null if this pathname does not name a parent directory.
File getParentFile()
Returns the abstract pathname of this abstract pathname's parent, or null if this pathname does not name a parent directory.
Return file in a directory
String[] list()
Returns an array of strings naming the files and directories in the directory denoted by this abstract pathname.
String[] list(FilenameFilter filter)
Returns an array of strings naming the files and directories in the directory denoted by this abstract pathname that satisfy the specified filter.
File[] listFiles()
Returns an array of abstract pathnames denoting the files in the directory denoted by this abstract pathname.
File[] listFiles(FileFilter filter)
Returns an array of abstract pathnames denoting the files and directories in the directory denoted by this abstract pathname that satisfy the specified filter.
File[] listFiles(FilenameFilter filter)
Returns an array of abstract pathnames denoting the files and directories in the directory denoted by this abstract pathname that satisfy the specified filter.
static File[] listRoots()
List the available filesystem roots.
Create new directories
boolean mkdir()
Creates the directory.
boolean mkdirs()
Creates the directory, including any necessary but nonexistent parent directories.
Rename file
boolean renameTo(File dest)
Renames the file denoted by this abstract pathname.
Change to executable, readable, writable
boolean setExecutable(boolean executable)
A convenience method to set the owner's execute permission for this abstract pathname.
boolean setExecutable(boolean executable, boolean ownerOnly)
Sets the owner's or everybody's execute permission for this abstract pathname.
boolean setLastModified(long time)
Sets the last-modified time of the file or directory named by this abstract pathname.
boolean setReadable(boolean readable)
A convenience method to set the owner's read permission for this abstract pathname.
boolean setReadable(boolean readable, boolean ownerOnly)
Sets the owner's or everybody's read permission for this abstract pathname.
boolean setReadOnly()
Marks the file or directory named by this abstract pathname so that only read operations are allowed.
boolean setWritable(boolean writable)
A convenience method to set the owner's write permission for this abstract pathname.
boolean setWritable(boolean writable, boolean ownerOnly)
Sets the owner's or everybody's write permission for this abstract pathname.
Change last-modified time
boolean setLastModified(long time)
Sets the last-modified time of the file or directory named by this abstract pathname.
Get string representation of a file location
String toString()
Returns the pathname string of this abstract pathname.
Convert file location to URI and URL
URI toURI()
Creates a file: URI that represents this abstract pathname.
Revised from Open JDK source code