Main.java Source code

Introduction

Here is the source code for Main.java

Source

import java.io.InputStream;
import java.net.URL;
import java.security.MessageDigest;

public class Main {
    public static void main(String[] args) throws Exception {
        URL source = new URL("http://www.a.com");
        URL mirror = new URL("http://www.b.com");
        byte[] sourceDigest = getDigestFromURL(source);
        byte[] mirrorDigest = getDigestFromURL(mirror);
        if (MessageDigest.isEqual(sourceDigest, mirrorDigest)) {
            System.out.println(mirror + " is up to date");
        } else {
            System.out.println(mirror + " needs to be updated");
        }
    }

    public static byte[] getDigestFromURL(URL u) throws Exception {
        MessageDigest md5 = MessageDigest.getInstance("MD5");
        InputStream in = u.openStream();
        byte[] data = new byte[1024];
        int bytesRead = -1;
        while ((bytesRead = in.read(data)) >= 0) {
            md5.update(data, 0, bytesRead);
        }
        return md5.digest();
    }
}