微信公众平台 java 开发详解（工程代码+解析）
说明：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：
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package demo.servlet;
import
import
import
import
import
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
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<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
xmlns="http://java.
xmlns:xsi="http://www.
xsi:schemaLocation="http://java.
http://java.
<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。
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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：
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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;
}
}
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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：
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package demo.process;
import
import
import
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.
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。
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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();
}
}
总结，以上便是微信公众平台开发的全部流程，整体来看并不复杂，要非常感谢图灵机器人提供的api接口，帮我们解决了智能回复这一高难度问题。其他类型的消息处理与示例中类似，有兴趣的开发者可以联系我进行交流学习，希望本文对大家有所帮助。
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