masher.java

一个java语言下的生成消息摘要的程序

import java.io.*;
import java.security.*;
import sun.misc.*;
public class Masher
{
    public static void main(String[] args) throws Exception
    {
        if (args.length!=1)
        {
            System.out.println("usage:Masher filename");
            return;
        }
        MessageDigest md=MessageDigest.getInstance("MD5");
        FileInputStream in=new FileInputStream(args[0]);
        byte[] buffer=new byte[8192];
        int length;
        while ((length=in.read(buffer))!=-1)
            md.update(buffer,0,length);
        byte[] raw=md.digest();
        BASE64Encoder encoder=new BASE64Encoder();
        String base64=encoder.encode(raw);
        System.out.println(base64);
    }
}