md5utils

 1 public class MD5Utils {
 2     /**
 3      * 使用md5的算法进行加密
 4      */
 5     public static String md5(String plainText) {
 6         byte[] secretBytes = null;
 7         try {
 8             secretBytes = MessageDigest.getInstance("md5").digest(
 9                     plainText.getBytes());
10         } catch (NoSuchAlgorithmException e) {
11             throw new RuntimeException("没有md5这个算法！");
12         }
13         String md5code = new BigInteger(1, secretBytes).toString(16);// 16进制数字
14         // 如果生成数字未满32位，需要前面补0
15         for (int i = 0; i < 32 - md5code.length(); i++) {
16             md5code = "0" + md5code;
17         }
18         return md5code;
19     }
20 
21     public static void main(String[] args) {
22         System.out.println(md5("1234"));
23     }
24 
25 }