package com.wtz.service;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import com.wtz.util.ValidationUtil;

/**
 * 　　@author wangtianze QQ:864620012
 * @date 2017年4月17日 下午8:11:32
 * <p>version:1.0</p>
 *  <p>description:微信请求验证类</p>
 */
public class LoginServlet extends HttpServlet {

 @Override
 protected void doGet(HttpServletRequest request, HttpServletResponse response)
   throws ServletException, IOException {
  System.out.println("get请求。。。。。。");
  
  //1.获得微信签名的加密字符串
  String signature = request.getParameter("signature");
  
  //2.获得时间戳信息
  String timestamp = request.getParameter("timestamp");
   
  //3.获得随机数
  String nonce = request.getParameter("nonce");
  
  //4.获得随机字符串
  String echostr = request.getParameter("echostr");
  
  System.out.println("获得微信签名的加密字符串："+signature);
  System.out.println("获得时间戳信息："+timestamp);
  System.out.println("获得随机数："+nonce);
  System.out.println("获得随机字符串："+echostr);
  
  PrintWriter out = response.getWriter();
  
  //验证请求确认成功原样返回echostr参数内容，则接入生效，成为开发者成功，否则失败
  if(ValidationUtil.checkSignature(signature, timestamp, nonce)){
   out.print(echostr);
  }
  
  out.close();
  out = null;
 }
}

package com.wtz.util;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;

/**
 *  @author wangtianze QQ:864620012
 * @date 2017年4月17日 下午8:35:57
 * <p>version:1.0</p>
 *  <p>description:微信请求校验工具类</p>
 */
public class ValidationUtil {
 private static String token = "wangtianze";
 
 public static boolean checkSignature(String signature,String timestamp,String nonce){
  //1.将token,timestamp,nonce三个参数进行排序
  String[] str = new String[]{token,timestamp,nonce};
  Arrays.sort(str);
  
  //2.将三个参数字符串拼接成一个字符串
  StringBuilder buff = new StringBuilder();
  for(int i=0;i<buff.length();i++){
   buff.append(str[i]);
  }
  
  //3.进行sha1加密
  MessageDigest md = null;
  String result = "";
  try {
   md = MessageDigest.getInstance("SHA-1");
   byte[] data = md.digest(buff.toString().getBytes());
   
   //将字节数组转换成字符串
   result = bytesToString(data);
   
   System.out.println("加密后的字符串为："+result);
   
  } catch (NoSuchAlgorithmException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  }
  
  return result!=null?(result.equals(signature.toUpperCase())):false;
 }
 
 /**
  * 将字节数组转换成十六进制字符串
  * @param byteArray
  * @return
  */
 private static String bytesToString(byte[] byteArray){
  String stringDigest = "";
  for(int i=0;i<stringDigest.length();i++){
   stringDigest += byteToHexString(byteArray[i]);
  }
  return stringDigest;
 }
 
 /**
  * 将一个字节转换为十六进制字符串
  * @param mByte
  * @return
  */
 private static String byteToHexString(byte mByte){
  char[] digit = {'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};
  char[] temp = new char[2];
  
  temp[0] = digit[(mByte>>>4) & 0X0F];
  temp[1] = digit[mByte & 0X0F];
  
  String str = new String(temp);
  return str;
 }
}