How to set the file permission in Java

By mkyong | Updated: August 29, 2012

Viewed: 3,807 (+22 pv/w)

Tags: file file permission io java

In Java, file permissions are very OS specific: *nix , NTFS (windows) and FAT/FAT32, all have different kind of file permissions. Java comes with some generic file permission to deal with it.

Check if the file permission allow :

1. file.canExecute(); – return true, file is executable; false is not.
2. file.canWrite(); – return true, file is writable; false is not.
3. file.canRead(); – return true, file is readable; false is not.

Set the file permission :

1. file.setExecutable(boolean); – true, allow execute operations; false to disallow it.
2. file.setReadable(boolean); – true, allow read operations; false to disallow it.
3. file.setWritable(boolean); – true, allow write operations; false to disallow it.

In *nix system, you may need to configure more specifies about file permission, e.g set a 777 permission for a file or directory, however, Java IO classes do not have ready method for it, but you can use the following dirty workaround :

Runtime.getRuntime().exec("chmod 777 file");

File permission example

package com.mkyong.file;

import java.io.File;
import java.io.IOException;

public class FilePermissionExample 
{
    public static void main( String[] args )
    {	
    	try {
    		 
	      File file = new File("/mkyong/shellscript.sh");
	      
	      if(file.exists()){
	    	  System.out.println("Is Execute allow : " + file.canExecute());
		  System.out.println("Is Write allow : " + file.canWrite());
		  System.out.println("Is Read allow : " + file.canRead());
	      }
	         
	      file.setExecutable(false);
	      file.setReadable(false);
	      file.setWritable(false);
	      
	      System.out.println("Is Execute allow : " + file.canExecute());
	      System.out.println("Is Write allow : " + file.canWrite());
	      System.out.println("Is Read allow : " + file.canRead());
	      
	      if (file.createNewFile()){
	        System.out.println("File is created!");
	      }else{
	        System.out.println("File already exists.");
	      }
	      
    	} catch (IOException e) {
	      e.printStackTrace();
	    }
    }
}

Reference

1. http://java.sun.com/javase/6/docs/api/java/io/File.html