java编程下字符串的16位,32位md5加密实现方法

package cn.sunzn.md5;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class Str2MD5 {

  public static void main(String[] args) {
    MD5("sunzn");
  }

  private static String MD5(String sourceStr) {
    String result = "";
    try {
      MessageDigest md = MessageDigest.getInstance("MD5");
      md.update(sourceStr.getBytes());
      byte b[] = md.digest();
      int i;
      StringBuffer buf = new StringBuffer("");
      for (int offset = 0; offset < b.length; offset++) {
        i = b[offset];
        if (i < 0)
          i += 256;
        if (i < 16)
          buf.append("0");
        buf.append(Integer.toHexString(i));
      }
      result = buf.toString();
      System.out.println("MD5(" + sourceStr + ",32) = " + result);
      System.out.println("MD5(" + sourceStr + ",16) = " + buf.toString().substring(8, 24));
    } catch (NoSuchAlgorithmException e) {
      System.out.println(e);
    }
    return result;
  }
}

MD5(sunzn,32) = 40379db889f9124819228947faaeb1f7
MD5(sunzn,16) = 89f9124819228947