MD5Encrypt.java

package com.gootrip.util;

import java.security.MessageDigest;

public class MD5Encrypt {

  public MD5Encrypt() {

  }

  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 byteArrayToString(byte[] b) {
    StringBuffer resultSb = new StringBuffer();
    for (int i = 0; i < b.length; i++) {
      resultSb.append(byteToHexString(b[i]));//若使用本函数转换则可得到加密结果的16进制表示，即数字字母混合的形式
//      resultSb.append(byteToNumString(b[i]));//使用本函数则返回加密结果的10进制数字字串，即全数字形式
    }
    return resultSb.toString();
  }

  private static String byteToNumString(byte b) {

    int _b = b;
    if (_b < 0) {
      _b = 256 + _b;
    }

    return String.valueOf(_b);
  }

  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 = byteArrayToString(md.digest(resultString.getBytes()));
    }
    catch (Exception ex) {
    	ex.printStackTrace();
    }
    return resultString;
  }
  /**
   * 
   * @param args
   */
  public static void main(String[] args) {
//    MD5Encrypt md5encrypt = new MD5Encrypt();
    System.out.println(MD5Encode("123456"));
  }
}