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) = 40379db889f9124819228947faaeb1f7MD5(sunzn,16) = 89f9124819228947