Hash value of the acquired object

package com.shzd.common.utils.utils;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.ObjectOutputStream;
import java.math.BigInteger;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

/**
 * MD5工具类
 */
public class MD5Utils {

    public static String md5(Object obj){

        byte[] dataBytes = getObjBytes(obj);
        //定义一个字节数组
        byte[] secretBytes = null;
        try {
            // 生成一个MD5加密计算摘要
            MessageDigest md = MessageDigest.getInstance("MD5");
            //对字符串进行加密
            md.update(dataBytes);
            //获得加密后的数据
            secretBytes = md.digest();
        } catch (NoSuchAlgorithmException e) {
            throw new RuntimeException("没有md5这个算法！");
        }
        //将加密后的数据转换为16进制数字
        String md5code = new BigInteger(1, secretBytes).toString(16);// 16进制数字
        // 如果生成数字未满32位，需要前面补0
        for (int i = 0; i < 32 - md5code.length(); i++) {
            md5code = "0" + md5code;
        }
        return md5code;
    }

    private static byte[] getObjBytes(Object obj) {
        ByteArrayOutputStream bos = new ByteArrayOutputStream();
        ObjectOutputStream oos = null;
        byte[] dataBytes = null;
        try {
            oos = new ObjectOutputStream(bos);
            oos.writeObject(obj);
            oos.flush();
            dataBytes = bos.toByteArray();
            oos.close();
            bos.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return dataBytes;
    }

    public static void main(String[] args) {
        System.out.println("123="+md5("123"));
    }
}