微信公众号开发一：接入指南

1.新建一个web project，我取的项目名称是weixin，使用8080端口，新建一个WeiXinServlet，web.xml如下

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" 
	xmlns="http://java.sun.com/xml/ns/javaee" 
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" 
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
	http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
  <display-name></display-name>
  
  <servlet>
    <servlet-name>WeiXinServlet</servlet-name>
    <servlet-class>com.gf.web.controller.WeiXinServlet</servlet-class>
  </servlet>

  <servlet-mapping>
    <servlet-name>WeiXinServlet</servlet-name>
    <url-pattern>/weiXinServlet</url-pattern>
  </servlet-mapping>
  
  	
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>

项目运行之后，我们就可以通过http://localhost:8080/weixin/weiXinServlet访问该servlet

2.下载ngrok，下载之后双击打开，在命令窗口输入ngrok http 8080回车

我马赛克注释掉的就是映射的外网访问地址，和后面的localhsot:8080访问一样。

http://注释掉/weixin/weiXinServlet和http://localhost:8080/weixin/weiXinServlet访问的是刚才新建的WeiXinServlet

3.登录微信公众号，我是申请的测试账号，左侧菜单“开发”下“基本配置”，配置如下

4.WeiXinServlet代码如下

package com.gf.web.controller;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class WeiXinServlet extends HttpServlet {

	private static String token = "pangpang";

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		String signature = request.getParameter("signature");
		String timestamp = request.getParameter("timestamp");
		String nonce = request.getParameter("nonce");
		String echostr = request.getParameter("echostr");
		
		System.out.println(signature);
//		System.out.println(timestamp);
//		System.out.println(nonce);
//		System.out.println(echostr);
		if(checkSignature(signature, timestamp, nonce)){
            response.getWriter().print(echostr);
        }


	}

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

	}

	public static boolean checkSignature(String signature, String timestamp,
			String nonce) {
		String[] arr = new String[] { token, timestamp, nonce };
		// 排序
		Arrays.sort(arr);

		// 生成字符串
		StringBuffer content = new StringBuffer();
		for (int i = 0; i < arr.length; i++) {
			content.append(arr[i]);
		}

		// sha1加密
		String temp = getSha1(content.toString());
		System.out.println(temp);
		return temp.equals(signature);

	}

	public static String getSha1(String str) {
		if (null == str || 0 == str.length()) {
			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 (NoSuchAlgorithmException e) {
			e.printStackTrace();
			return null;
		} catch (UnsupportedEncodingException e) {
			e.printStackTrace();
			return null;
		}
	}

}

5.提交第三步的配置，bingo。