How To Set The File Permission In 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.mitul.file;
 
import java.io.File;
import java.io.IOException;
 
public class FilePermissionExample 
{
    public static void main( String[] args )
    { 
     try {
 
       File file = new File("/mitul/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();
     }
    }
}