What are the classes in Java available for file
handling
Ans
Files and directories are
accessed and manipulated by the File class. The File class does not actually
provide for input and output to files. It simply provides an identifier of
files and directories.Note: Always remember
that just because a File object is created, it does not mean there actually
exists on the disk a file with the identifier held by that File object.For Defining a file in
a File Class there are several types of constructors.
File Class
constructors:
Constructor Description
File(File parent,
String child) This method creates a new
File instance from a parent abstract pathname and a child pathname string.
File(String pathname) This method creates a new File instance by
converting the given pathname string into an abstract pathname
File(String parent,
String child) This method creates
a new File instance from a parent pathname string and a child pathname string.
File(String parent,
String child) This method Creates
a new File instance by converting the given file: URI into an abstract
pathname.
File class methods:
Method Description
Boolean canExecute() This method tests whether the application can
execute the file denoted by this abstract pathname.
Boolean canRead() This method tests whether the application
can read the file denoted by this abstract pathname.
Boolean canWrite() This method tests whether the application
can modify the file denoted by this abstract pathname.
int compareTo (File
pathname) This method compares
two abstract pathnames.
Boolean createNewFile() This method atomically creates a new,
empty file named by this abstract pathname if and only if a file with this name
does not yet exist.
Boolean delete() This method deletes the file or
directory denoted by this abstract pathname.
long getFreeSpace() This method returns the number of
unallocated bytes in the partition named by this abstract path name.
String getName() This method returns the name of the file
or directory denoted by this abstract pathname.
String getParent() This method returns the pathname string
of this abstract pathname's parent, or null if this pathname does not name a
parent directory.
File getParentFile() This method returns the abstract pathname
of this abstract pathname's parent, or null if this pathname does not name a
parent directory.
String getPath() This method converts this abstract
pathname into a pathname string.
String toString() This method returns the pathname
string of this abstract pathname.
Boolean mkdir() This method creates the directory
named by this abstract pathname.
long getTotalSpace() This method returns the size of the partition
named by this abstract pathname.
long getUsableSpace() This method returns the number of
bytes available to this virtual machine on the partition named by this abstract
pathname.
int hashCode() This method computes a hash code for
this abstract pathname.
Boolean isAbsolute() This method tests whether this abstract
pathname is absolute.
Boolean isDirectory() This method tests whether the file denoted by
this abstract pathname is a directory.
Boolean isFile() This method tests whether the file
denoted by this abstract pathname is a normal file.
Boolean isHidden() This method tests whether the file named by
this abstract pathname is a hidden file.
long lastModified() This method returns the time that the file
denoted by this abstract pathname was last modified
long length() This method returns the length of the file
denoted by this abstract pathname.
String[] list() This method returns an array of strings
naming the files and directories in the directory denoted by this abstract
pathname
String[] list(Filename
Filter filter) This method 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() This method returns an array of
abstract pathnames denoting the files in the directory denoted by this abstract
pathname.
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