一个实现MD5的简洁的java类

一个实现MD5的简洁的java类

package test;
import java.security.MessageDigest;

public class StringUtil {

   private final static String[] hexDigits = {
       "0", "1", "2", "3", "4", "5", "6", "7",
       "8", "9", "a", "b", "c", "d", "e", "f"};

   /**
    * 转换字节数组为16进制字串
    * @param b 字节数组
    * @return 16进制字串
    */

   public static String byteArrayToHexString(byte[] b) {
     StringBuffer resultSb = new StringBuffer();
     for (int i = 0; i < b.length; i++) {
       resultSb.append(byteToHexString(b[i]));
     }
     return resultSb.toString();
   }

   private static String byteToHexString(byte b) {
     int n = b;
     if (n < 0)
       n = 256 + n;
     int d1 = n / 16;
     int d2 = n % 16;
     return hexDigits[d1] + hexDigits[d2];
   }

   public static String MD5Encode(String origin) {
     String resultString = null;

     try {
       resultString=new String(origin);
       MessageDigest md = MessageDigest.getInstance("MD5");
       resultString=byteArrayToHexString(md.digest(resultString.getBytes()));
     }
     catch (Exception ex) {

     }
     return resultString;
   }

   public static void main(String[] args){
     System.err.println(MD5Encode("a"));
   }
}