How to check a file is modified at a server or not in Java

Problem Description

How to check a file is modified at a server or not?

Solution

Following example shows How to check a file is modified at a server or not.

import java.net.URL;
import java.net.URLConnection;

public class Main {
   public static void main(String[] argv)throws Exception {
      URL u = new URL("http://127.0.0.1/java.bmp");
      URLConnection uc = u.openConnection();
      uc.setUseCaches(false);
      long timestamp = uc.getLastModified();
      System.out.println("The last modification time of java.bmp is :"+timestamp);
   }
}

Result

The above code sample will produce the following result.

The last modification time of java.bmp is :24 May 2009 12:14:50

The following is an example to check a file is modified at a server or not.

import java.net.URL;
import java.net.URLConnection;

public class Main {
   public static void main(String[] argv)throws Exception {
      URL u = new URL(
         "https://www.tutorialspoint.com/cpp_standard_library/cpp_fstream_close.htm");
      
      URLConnection uc = u.openConnection();
      uc.setUseCaches(false);
      long timestamp = uc.getLastModified();
      System.out.println("The last modification time of file is :"+timestamp);
   }
}

The above code sample will produce the following result.

The last modification time of file is :1479867073000