微信公众号开发

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="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">
  <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。

下面就讲解其核心部分——解析接收到的xml数据，并以文本类消息为例，通过图灵机器人api接口实现智能回复。


2.1 首先看一下整体流程处理代码，包括：xml数据处理、调用图灵api、封装返回的xml数据。

package demo.process;

import java.util.Date;

import demo.entity.ReceiveXmlEntity;

/**
 * 微信xml消息处理流程逻辑类
 * @author pamchen-1
 *
 */
public class WechatProcess {
    /**
     * 解析处理xml、获取智能回复结果（通过图灵机器人api接口）
     * @param xml 接收到的微信数据
     * @return  最终的解析结果（xml格式数据）
     */
    public String processWechatMag(String xml){
        /** 解析xml数据 */
        ReceiveXmlEntity xmlEntity = new ReceiveXmlProcess().getMsgEntity(xml);

        /** 以文本消息为例，调用图灵机器人api接口，获取回复内容 */
        String result = "";
        if("text".endsWith(xmlEntity.getMsgType())){
            result = new TulingApiProcess().getTulingResult(xmlEntity.getContent());
        }

        /** 此时，如果用户输入的是“你好”，在经过上面的过程之后，result为“你也好”类似的内容
         *  因为最终回复给微信的也是xml格式的数据，所有需要将其封装为文本类型返回消息
         * */
        result = new FormatXmlProcess().formatXmlAnswer(xmlEntity.getFromUserName(), xmlEntity.getToUserName(), result);

        return result;
    }
}

2.2 解析接收到的xml数据，此处有两个类，ReceiveXmlEntity.java和ReceiveXmlProcess.java，通过反射的机制动态调用实体类中的set方法，可以避免很多重复的判断，提高代码效率，代码如下：

package demo.entity;
/**
 * 接收到的微信xml实体类
 * @author pamchen-1
 *
 */
public class ReceiveXmlEntity {
    private String ToUserName="";
    private String FromUserName="";
    private String CreateTime="";
    private String MsgType="";
    private String MsgId="";
    private String Event="";
    private String EventKey="";
    private String Ticket="";
    private String Latitude="";
    private String Longitude="";
    private String Precision="";
    private String PicUrl="";
    private String MediaId="";
    private String Title="";
    private String Description="";
    private String Url="";
    private String Location_X="";
    private String Location_Y="";
    private String Scale="";
    private String Label="";
    private String Content="";
    private String Format="";
    private String Recognition="";

    public String getRecognition() {
        return Recognition;
    }
    public void setRecognition(String recognition) {
        Recognition = recognition;
    }
    public String getFormat() {
        return Format;
    }
    public void setFormat(String format) {
        Format = format;
    }
    public String getContent() {
        return Content;
    }
    public void setContent(String content) {
        Content = content;
    }
    public String getLocation_X() {
        return Location_X;
    }
    public void setLocation_X(String locationX) {
        Location_X = locationX;
    }
    public String getLocation_Y() {
        return Location_Y;
    }
    public void setLocation_Y(String locationY) {
        Location_Y = locationY;
    }
    public String getScale() {
        return Scale;
    }
    public void setScale(String scale) {
        Scale = scale;
    }
    public String getLabel() {
        return Label;
    }
    public void setLabel(String label) {
        Label = label;
    }
    public String getTitle() {
        return Title;
    }
    public void setTitle(String title) {
        Title = title;
    }
    public String getDescription() {
        return Description;
    }
    public void setDescription(String description) {
        Description = description;
    }
    public String getUrl() {
        return Url;
    }
    public void setUrl(String url) {
        Url = url;
    }
    public String getPicUrl() {
        return PicUrl;
    }
    public void setPicUrl(String picUrl) {
        PicUrl = picUrl;
    }
    public String getMediaId() {
        return MediaId;
    }
    public void setMediaId(String mediaId) {
        MediaId = mediaId;
    }
    public String getEventKey() {
        return EventKey;
    }
    public void setEventKey(String eventKey) {
        EventKey = eventKey;
    }
    public String getTicket() {
        return Ticket;
    }
    public void setTicket(String ticket) {
        Ticket = ticket;
    }
    public String getLatitude() {
        return Latitude;
    }
    public void setLatitude(String latitude) {
        Latitude = latitude;
    }
    public String getLongitude() {
        return Longitude;
    }
    public void setLongitude(String longitude) {
        Longitude = longitude;
    }
    public String getPrecision() {
        return Precision;
    }
    public void setPrecision(String precision) {
        Precision = precision;
    }
    public String getEvent() {
        return Event;
    }
    public void setEvent(String event) {
        Event = event;
    }
    public String getMsgId() {
        return MsgId;
    }
    public void setMsgId(String msgId) {
        MsgId = msgId;
    }
    public String getToUserName() {
        return ToUserName;
    }
    public void setToUserName(String toUserName) {
        ToUserName = toUserName;
    }
    public String getFromUserName() {
        return FromUserName;
    }
    public void setFromUserName(String fromUserName) {
        FromUserName = fromUserName;
    }
    public String getCreateTime() {
        return CreateTime;
    }
    public void setCreateTime(String createTime) {
        CreateTime = createTime;
    }
    public String getMsgType() {
        return MsgType;
    }
    public void setMsgType(String msgType) {
        MsgType = msgType;
    }
}

package demo.process;

import java.lang.reflect.Field;
import java.lang.reflect.Method;
import java.util.Iterator;
import org.dom4j.Document;
import org.dom4j.DocumentHelper;
import org.dom4j.Element;

import demo.entity.ReceiveXmlEntity;
/**
 * 解析接收到的微信xml，返回消息对象
 * @author pamchen-1
 *
 */
public class ReceiveXmlProcess {
    /**
     * 解析微信xml消息
     * @param strXml
     * @return
     */
    public ReceiveXmlEntity getMsgEntity(String strXml){
        ReceiveXmlEntity msg = null;
        try {
            if (strXml.length() <= 0 || strXml == null)
                return null;

            // 将字符串转化为XML文档对象
            Document document = DocumentHelper.parseText(strXml);
            // 获得文档的根节点
            Element root = document.getRootElement();
            // 遍历根节点下所有子节点
            Iterator<?> iter = root.elementIterator();

            // 遍历所有结点
            msg = new ReceiveXmlEntity();
            //利用反射机制，调用set方法
            //获取该实体的元类型
            Class<?> c = Class.forName("demo.entity.ReceiveXmlEntity");
            msg = (ReceiveXmlEntity)c.newInstance();//创建这个实体的对象

            while(iter.hasNext()){
                Element ele = (Element)iter.next();
                //获取set方法中的参数字段（实体类的属性）
                Field field = c.getDeclaredField(ele.getName());
                //获取set方法，field.getType())获取它的参数数据类型
                Method method = c.getDeclaredMethod("set"+ele.getName(), field.getType());
                //调用set方法
                method.invoke(msg, ele.getText());
            }
        } catch (Exception e) {
            // TODO: handle exception
            System.out.println("xml 格式异常: "+ strXml);
            e.printStackTrace();
        }
        return msg;
    }
}

2.3 调用图灵机器人api接口，获取智能回复内容：

package demo.process;

import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;

import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import org.json.JSONException;
import org.json.JSONObject;

/**
 * 调用图灵机器人api接口，获取智能回复内容
 * @author pamchen-1
 *
 */
public class TulingApiProcess {
    /**
     * 调用图灵机器人api接口，获取智能回复内容，解析获取自己所需结果
     * @param content
     * @return
     */
    public String getTulingResult(String content){
        /** 此处为图灵api接口，参数key需要自己去注册申请，先以11111111代替 */
        String apiUrl = "http://www.tuling123.com/openapi/api?key=11111111&info=";
        String param = "";
        try {
            param = apiUrl+URLEncoder.encode(content,"utf-8");
        } catch (UnsupportedEncodingException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        } //将参数转为url编码

        /** 发送httpget请求 */
        HttpGet request = new HttpGet(param);
        String result = "";
        try {
            HttpResponse response = HttpClients.createDefault().execute(request);
            if(response.getStatusLine().getStatusCode()==200){
                result = EntityUtils.toString(response.getEntity());
            }
        } catch (ClientProtocolException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        /** 请求失败处理 */
        if(null==result){
            return "对不起，你说的话真是太高深了……";
        }

        try {
            JSONObject json = new JSONObject(result);
            //以code=100000为例，参考图灵机器人api文档
            if(100000==json.getInt("code")){
                result = json.getString("text");
            }
        } catch (JSONException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        return result;
    }
}

2.4 将结果封装为微信规定的xml格式，并返回给1.1中创建的servlet接口。

package demo.process;

import java.util.Date;
/**
 * 封装最终的xml格式结果
 * @author pamchen-1
 *
 */
public class FormatXmlProcess {
    /**
     * 封装文字类的返回消息
     * @param to
     * @param from
     * @param content
     * @return
     */
    public String formatXmlAnswer(String to, String from, String content) {
        StringBuffer sb = new StringBuffer();
        Date date = new Date();
        sb.append("<xml><ToUserName><![CDATA[");
        sb.append(to);
        sb.append("]]></ToUserName><FromUserName><![CDATA[");
        sb.append(from);
        sb.append("]]></FromUserName><CreateTime>");
        sb.append(date.getTime());
        sb.append("</CreateTime><MsgType><![CDATA[text]]></MsgType><Content><![CDATA[");
        sb.append(content);
        sb.append("]]></Content><FuncFlag>0</FuncFlag></xml>");
        return sb.toString();
    }
}