学步园

  
 （3）搭建好 Java 开发环境，没有搭建好的可参考 Java 开发环境搭建

package org.ivy.course.servlet;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
 * Servlet implementation class CoreServlet
 */
@WebServlet("/CoreServlet")
public class CoreServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;
    /**
     * Default constructor. 
     */
    public CoreServlet() {
        // TODO Auto-generated constructor stub
    }
    /**
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
    }
    /**
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
    }
}

package org.ivy.course.servlet;

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

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

import org.ivy.course.util.SignUtil;

/**
 * Servlet implementation class CoreServlet
 */
@WebServlet("/CoreServlet")
public class CoreServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    /**
     * Default constructor. 
     */
    public CoreServlet() {
        // TODO Auto-generated constructor stub
    }

    /**
     * 确认请求来自微信服务器
     * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        
        // my
        // 微信加密签名
        String signature = request.getParameter("signature");
        // 时间戮
        String timestamp = request.getParameter("timestamp");
        // 随机数
        String nonce = request.getParameter("nonce");
        // 随机字符串
        String echostr = request.getParameter("echostr"); 
        
        PrintWriter out = response.getWriter();
        // 通过检验 signature 对请求进行校验，若校验成功则原样返回 echostr，表示接入成功，否则接入失败
       if(SignUtil.checkSignature(signature, timestamp, nonce)){
           out.print(echostr);
       }

       out.close();
       out = null;        
    }

    /**
     * 处理微信服务器发来的消息 
     * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO Auto-generated method stub
        // 消息的接收、处理、响应  
    }

}

在doGet方法中调用了checkSignature方法，该方法还没有实现，我们新建一个包
org.ivy.course.util 作为一个工具包，并往该包中添加新类 SignUtil，添加类的方法是：包名右键 -->new --> class，填上类名，其它默认，完整代码如下：

package org.ivy.course.util;

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

public class SignUtil {
    /**
     * 与接口配置信息中的 token 要一致，这里赋予什么值，在接口配置信息中的Token就要填写什么值，
     * 两边保持一致即可，建议用项目名称、公司名称缩写等，我在这里用的是项目名称weixinface
     */
    private static String token = "weixinface";
    
    /**
     * 验证签名
     * @param signature
     * @param timestamp
     * @param nonce
     * @return
     */
    public static boolean checkSignature(String signature, String timestamp, String nonce){
        String[] arr = new String[]{token, timestamp, nonce};
        // 将 token, timestamp, nonce 三个参数进行字典排序
        Arrays.sort(arr);
        StringBuilder content = new StringBuilder();
        for(int i = 0; i < arr.length; i++){
            content.append(arr[i]);
        }
        MessageDigest md = null;
        String tmpStr = null;
        
        try {
            md = MessageDigest.getInstance("SHA-1");
            // 将三个参数字符串拼接成一个字符串进行 shal 加密
            byte[] digest = md.digest(content.toString().getBytes());
            tmpStr = byteToStr(digest);
        } catch (NoSuchAlgorithmException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        content = null;
        // 将sha1加密后的字符串可与signature对比，标识该请求来源于微信
        return tmpStr != null ? tmpStr.equals(signature.toUpperCase()): false;
    }
    
    /**
     * 将字节数组转换为十六进制字符串
     * @param digest
     * @return
     */
    private static String byteToStr(byte[] digest) {
        // TODO Auto-generated method stub
        String strDigest = "";
        for(int i = 0; i < digest.length; i++){
            strDigest += byteToHexStr(digest[i]);
        }
        return strDigest;
    }
    
    /**
     * 将字节转换为十六进制字符串
     * @param b
     * @return
     */
    private static String byteToHexStr(byte b) {
        // TODO Auto-generated method stub
        char[] Digit = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F'};
        char[] tempArr = new char[2];
        tempArr[0] = Digit[(b >>> 4) & 0X0F];
        tempArr[1] = Digit[b & 0X0F];
        
        String s = new String(tempArr);
        return s;
    }
}

代码添加完毕，工程右键，删除工程中的
ROOT.war 包,  然后工程右键重新打包一个
ROOT.war 包，名字必须和原来一样，保存地址也和原来一样，具体是，右键 -->  Export --> WAR file：