import java.math.BigInteger;

import java.security.MessageDigest;

public class AppMD5Util {

     /**

    * 对字符串md5加密(小写+字母)

    *

    * @param str 传入要加密的字符串

    * @return  MD5加密后的字符串

    */

   public static String littleMD5a(String str) {

       try {

           // 生成一个MD5加密计算摘要

           MessageDigest md = MessageDigest.getInstance("MD5");

           // 计算md5函数

           md.update(str.getBytes());

           // digest()最后确定返回md5 hash值，返回值为8为字符串。因为md5 hash值是16位的hex值，实际上就是8位的字符

           // BigInteger函数则将8位的字符串转换成16位hex值，用字符串来表示；得到字符串形式的hash值

           return new BigInteger(1, md.digest()).toString(16);

       } catch (Exception e) {

          e.printStackTrace();

          return null;

       }

   }

   // 16位是将32位中的16截取出来

    public static String little16MD5a(String str) {

        return littleMD5a(str).substring(8, 24);

    }

   /**

    * 对字符串md5加密(大写+数字)

    *

    * @param str 传入要加密的字符串

    * @return  MD5加密后的字符串

    */

   public static String BigMD55(String string) {

       char hexDigits[]={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};       

       try {

           byte[] btInput = string.getBytes();

           // 获得MD5摘要算法的 MessageDigest 对象

           MessageDigest mdInst = MessageDigest.getInstance("MD5");

           // 使用指定的字节更新摘要

           mdInst.update(btInput);

           // 获得密文

           byte[] md = mdInst.digest();

           // 把密文转换成十六进制的字符串形式

           int j = md.length;

           char str[] = new char[j * 2];

           int k = 0;

           for (int i = 0; i < j; i++) {

               byte byte0 = md[i];

               str[k++] = hexDigits[byte0 >>> 4 & 0xf];

               str[k++] = hexDigits[byte0 & 0xf];

           }

           return new String(str);

       } catch (Exception e) {

           e.printStackTrace();

           return null;

       }

   }

    // 16位是将32位中的16截取出来

    public static String Big16MD55(String str) {

        return BigMD55(str).substring(8, 24);

    }

   //获取SHA1加密值

   public static String getSHA1(String str){

       if(str==null||str.length()==0){

           return null;

       }

       char hexDigits[] = {'0','1','2','3','4','5','6','7','8','9',

               'a','b','c','d','e','f'};

       try {

           MessageDigest mdTemp = MessageDigest.getInstance("SHA1");

           mdTemp.update(str.getBytes("UTF-8"));

           byte[] md = mdTemp.digest();

           int j = md.length;

           char buf[] = new char[j*2];

           int k = 0;

           for (int i = 0; i < j; i++) {

               byte byte0 = md[i];

               buf[k++] = hexDigits[byte0 >>> 4 & 0xf];

               buf[k++] = hexDigits[byte0 & 0xf];

           }

           return new String(buf);

       } catch (Exception e) {

           return null;

       }

   }  

    public static void main(String[] args) {

        String bigmd5 = BigMD55("miniprograme");

        System.err.println("32大写加数字  "+bigmd5);

        long Time13 = System.currentTimeMillis();

        System.out.println(Time13);

        String postbigmd5time = "POST"+bigmd5+ Time13;

        System.err.println("post32大写加数字 时间戳  "+ postbigmd5time);

        System.out.println("最终的sign值  "+ getSHA1(postbigmd5time));

        System.err.println("最终的sign值  "+ getSHA1(postbigmd5time));

        System.out.println(Time13);

    }

}