本次的教程主要是对微信公众平台开发者模式的讲解，网络上很多类似文章，但很多都让初学微信开发的人一头雾水，所以总结自己的微信开发经验，将微信开发的整个过程系统的列出，并对主要代码进行讲解分析，让初学者尽快上手。
在阅读本文之前，应对微信公众平台的官方开发文档有所了解，知道接收和发送的都是xml格式的数据。另外，在做内容回复时用到了图灵机器人的api接口，这是一个自然语言解析的开放平台，可以帮我们解决整个微信开发过程中最困难的问题，此处不多讲，下面会有其详细的调用方式。
1.1 在登录微信官方平台之后，开启开发者模式，此时需要我们填写url和token，所谓url就是我们自己服务器的接口，用WechatServlet.java来实现，相关解释已经在注释中说明，代码如下：
package demo.servlet;import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import demo.process.WechatProcess;
/**
* 微信服务端收发消息接口
*
* @author pamchen-1
*
*/
public class WechatServlet extends HttpServlet {
/**
* The doGet method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to get.
*
* @param request
* the request send by the client to the server
* @param response
* the response send by the server to the client
* @throws ServletException
* if an error occurred
* @throws IOException
* if an error occurred
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
request.setCharacterEncoding("UTF-8");
response.setCharacterEncoding("UTF-8");
/** 读取接收到的xml消息 */
StringBuffer sb = new StringBuffer();
InputStream is = request.getInputStream();
InputStreamReader isr = new InputStreamReader(is, "UTF-8");
BufferedReader br = new BufferedReader(isr);
String s = "";
while ((s = br.readLine()) != null) {
sb.append(s);
}
String xml = sb.toString(); //次即为接收到微信端发送过来的xml数据
String result = "";
/** 判断是否是微信接入激活验证，只有首次接入验证时才会收到echostr参数，此时需要把它直接返回 */
String echostr = request.getParameter("echostr");
if (echostr != null && echostr.length() > 1) {
result = echostr;
} else {
//正常的微信处理流程
result = new WechatProcess().processWechatMag(xml);
}
try {
OutputStream os = response.getOutputStream();
os.write(result.getBytes("UTF-8"));
os.flush();
os.close();
} catch (Exception e) {
e.printStackTrace();
}
}
/**
* The doPost method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to
* post.
*
* @param request
* the request send by the client to the server
* @param response
* the response send by the server to the client
* @throws ServletException
* if an error occurred
* @throws IOException
* if an error occurred
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
}
1.2 相应的web.xml配置信息如下，在生成WechatServlet.java的同时，可自动生成web.xml中的配置。前面所提到的url处可以填写例如：http;//服务器地址/项目名/wechat.do
<?xml version="1.0" encoding="UTF-8"?><web-app version="2.5"
xmlns=""
xmlns:xsi=""
xsi:schemaLocation="
">
<servlet>
<description>This is the description of my J2EE component</description>
<display-name>This is the display name of my J2EE component</display-name>
<servlet-name>WechatServlet</servlet-name>
<servlet-class>demo.servlet.WechatServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>WechatServlet</servlet-name>
<url-pattern>/wechat.do</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
1.3 通过以上代码，我们已经实现了微信公众平台开发的框架，即开通开发者模式并成功接入、接收消息和发送消息这三个步骤。