MD5摘要

package com.tarena.util;import java.security.MessageDigest;import java.security.NoSuchAlgorithmException;?public class MD5Util {  /**   * 将原文str经过MD5摘要算法得到密文   * @param str 如: 1234   * @return "1234" 的摘要   */  public static String md5(String str){    try {      MessageDigest md = MessageDigest.getInstance("MD5");      md.update(str.getBytes());      byte[] md5 = md.digest();      char[] ch = "0123456789abcdef".toCharArray();      StringBuilder buf = new StringBuilder();      for (byte b : md5) {        buf.append(ch[ b>>>4 & 0xf ]);        buf.append(ch[ b& 0xf ]);      }      return buf.toString();    } catch (NoSuchAlgorithmException e) {      e.printStackTrace();      throw new RuntimeException(e);    }  }    public static void main(String[] args) {    System.out.println(md5("1234"));  }}