java的MD5算法

package sysFrame;
import java.security.MessageDigest;
public class Test_MD5{
public final static String MD5(String s) {
  char hexDigits[] = { '0', '1', '2', '3', '4', '5', '6', '7', '8',
                       '9', 'a', 'b', 'c', 'd', 'e', 'f' };
  try {
     byte[] strTemp = s.getBytes();
     //使用MD5创建MessageDigest对象
     MessageDigest mdTemp = MessageDigest.getInstance("MD5");
     mdTemp.update(strTemp);
     byte[] md = mdTemp.digest();
     int j = md.length;
     char str[] = new char[j * 2];

     int k = 0;
     for (int i = 0; i < j; i++) {
          byte b = md[i];
         //System.out.println((int)b);
        //将没个数(int)b进行双字节加密
        str[k++] = hexDigits[b >> 4 & 0xf];
        str[k++] = hexDigits[b & 0xf];
   }

   return new String(str);
  } catch (Exception e) {return null;}
}

  //测试
public static void main(String[] args) {
  System.out.println("caidao的MD5加密后：\n"+Test_MD5.MD5("caidao"));
  System.out.println("http://www.baidu.com/的MD5加密后：\n"+Test_MD5.MD5("http://www.baidu.com/"));
}
}