md5算法代码



package com.bjhj.castest;

import java.security.MessageDigest;

public class myDigest {
 
 public static void main(String[] args) {
  myDigest my = new myDigest();
  my.testDigest("我的测试信息");
 }

 public void testDigest(String myinfo) {
  try {
   MessageDigest alga = MessageDigest.getInstance("MD5");
   alga.update(myinfo.getBytes());
   byte[] digesta = alga.digest();
   System.out.println("本信息摘要是:" + byte2hex(digesta));
   // 通过某中方式传给其他人你的信息(myinfo)和摘要(digesta) 对方可以判断是否更改或传输正常
   MessageDigest algb = MessageDigest.getInstance("MD5");
   algb.update(myinfo.getBytes());
   if (MessageDigest.isEqual(digesta, algb.digest())) {
    System.out.println("信息检查正常");
   } else {
    System.out.println("摘要不相同");
   }
  } catch (java.security.NoSuchAlgorithmException ex) {
   System.out.println("非法摘要算法");
  }
 }

 public String byte2hex(byte[] b) // 二行制转字符串
 {
  String hs = "";
  String stmp = "";
  for (int n = 0; n < b.length; n++) {
   stmp = (Integer.toHexString(b[n] & 0XFF));
   if (stmp.length() == 1)
    hs = hs + "0" + stmp;
   else
    hs = hs + stmp;
   if (n < b.length - 1)
    hs = hs + ":";
  }
  return hs.toUpperCase();
 }
}