MD5加密工具

import java.math.BigInteger;import java.security.MessageDigest;import java.security.NoSuchAlgorithmException;public class MD5Utils {    /**     * 使用md5的算法进行加密     */    public static String md5(String plainText) {        byte[] secretBytes = null;        try {            secretBytes = MessageDigest.getInstance("md5").digest(                    plainText.getBytes());        } catch (NoSuchAlgorithmException e) {            throw new RuntimeException("没有md5这个算法！");        }        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;    }    public static void main(String[] args) {        System.out.println(md5("123"));    }}