Java File Class

The File class is an abstract representation of file and directory pathname. A pathname can be either absolute or relative.

The File class have several methods for working with directories and files such as creating new directories or files, deleting and renaming directories or files, listing the contents of a directory etc.

Fields

Modifier	Type	Field	Description
static	String	pathSeparator	It is system-dependent path-separator character, represented as a string for convenience.
static	char	pathSeparatorChar	It is system-dependent path-separator character.
static	String	separator	It is system-dependent default name-separator character, represented as a string for convenience.
static	char	separatorChar	It is system-dependent default name-separator character.

Constructors

Constructor	Description
File(File parent, String child)	It creates a new File instance from a parent abstract pathname and a child pathname string.
File(String pathname)	It creates a new File instance by converting the given pathname string into an abstract pathname.
File(String parent, String child)	It creates a new File instance from a parent pathname string and a child pathname string.
File(URI uri)	It creates a new File instance by converting the given file: URI into an abstract pathname.

Useful Methods

Modifier and Type	Method	Description
static File	createTempFile(String prefix, String suffix)	It creates an empty file in the default temporary-file directory, using the given prefix and suffix to generate its name.
boolean	createNewFile()	It 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	canWrite()	It tests whether the application can modify the file denoted by this abstract pathname.String[]
boolean	canExecute()	It tests whether the application can execute the file denoted by this abstract pathname.
boolean	canRead()	It tests whether the application can read the file denoted by this abstract pathname.
boolean	isAbsolute()	It tests whether this abstract pathname is absolute.
boolean	isDirectory()	It tests whether the file denoted by this abstract pathname is a directory.
boolean	isFile()	It tests whether the file denoted by this abstract pathname is a normal file.
String	getName()	It returns the name of the file or directory denoted by this abstract pathname.
String	getParent()	It returns the pathname string of this abstract pathname's parent, or null if this pathname does not name a parent directory.
Path	toPath()	It returns a java.nio.file.Path object constructed from the this abstract path.
URI	toURI()	It constructs a file: URI that represents this abstract pathname.
File[]	listFiles()	It returns an array of abstract pathnames denoting the files in the directory denoted by this abstract pathname
long	getFreeSpace()	It returns the number of unallocated bytes in the partition named by this abstract path name.
String[]	list(FilenameFilter filter)	It returns an array of strings naming the files and directories in the directory denoted by this abstract pathname that satisfy the specified filter.
boolean	mkdir()	It creates the directory named by this abstract pathname.

Java File Example 1

import java.io.*;
public class FileDemo {
	public static void main(String[] args) {

		try {
			File file = new File("javaFile123.txt");
			if (file.createNewFile()) {
				System.out.println("New File is created!");
			} else {
				System.out.println("File already exists.");
			}
		} catch (IOException e) {
			e.printStackTrace();
		}

	}
}

Output:

New File is created!

Java File Example 2

import java.io.*;
public class FileDemo2 {
	public static void main(String[] args) {

		String path = "";
		boolean bool = false;
		try {
			// createing  new files
			File file  = new File("testFile1.txt");
			file.createNewFile();
			System.out.println(file);
			// createing new canonical from file object
			File file2 = file.getCanonicalFile();
			// returns true if the file exists
			System.out.println(file2);
			bool = file2.exists();
			// returns absolute pathname
			path = file2.getAbsolutePath();
			System.out.println(bool);
			// if file exists
			if (bool) {
				// prints
				System.out.print(path + " Exists? " + bool);
			}
		} catch (Exception e) {
			// if any error occurs
			e.printStackTrace();
		}
	}
}

Output:

testFile1.txt
/home/Work/Project/File/testFile1.txt
true
/home/Work/Project/File/testFile1.txt Exists? true

Java File Example 3

import java.io.*;
public class FileExample {
public static void main(String[] args) {
	File f=new File("/Users/sonoojaiswal/Documents");
	String filenames[]=f.list();
	for(String filename:filenames){
		System.out.println(filename);
	}
}
}

Output:

"info.properties"
"info.properties".rtf
.DS_Store
.localized
Alok news
apache-tomcat-9.0.0.M19
apache-tomcat-9.0.0.M19.tar
bestreturn_org.rtf
BIODATA.pages
BIODATA.pdf
BIODATA.png
struts2jars.zip
workspace

Java File Example 4

import java.io.*;
public class FileExample {
public static void main(String[] args) {
	File dir=new File("/Users/sonoojaiswal/Documents");
	File files[]=dir.listFiles();
	for(File file:files){
		System.out.println(file.getName()+" Can Write: "+file.canWrite()+" 
		Is Hidden: "+file.isHidden()+" Length: "+file.length()+" bytes");
	}
}
}

Output:

"info.properties" Can Write: true Is Hidden: false Length: 15 bytes
"info.properties".rtf Can Write: true Is Hidden: false Length: 385 bytes
.DS_Store Can Write: true Is Hidden: true Length: 36868 bytes
.localized Can Write: true Is Hidden: true Length: 0 bytes
Alok news Can Write: true Is Hidden: false Length: 850 bytes
apache-tomcat-9.0.0.M19 Can Write: true Is Hidden: false Length: 476 bytes
apache-tomcat-9.0.0.M19.tar Can Write: true Is Hidden: false Length: 13711360 bytes
bestreturn_org.rtf Can Write: true Is Hidden: false Length: 389 bytes
BIODATA.pages Can Write: true Is Hidden: false Length: 707985 bytes
BIODATA.pdf Can Write: true Is Hidden: false Length: 69681 bytes
BIODATA.png Can Write: true Is Hidden: false Length: 282125 bytes
workspace Can Write: true Is Hidden: false Length: 1972 bytes

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