微信公众平台开发教程Java版(三) 消息接收和发送

前面两章已经介绍了如何接入微信公众平台，这一章说说消息的接收和发送

可以先了解公众平台的消息api接口（接收消息，发送消息）

http://mp./wiki/index.php

接收消息

当普通微信用户向公众账号发消息时，微信服务器将POST消息的XML数据包到开发者填写的URL上。

http://mp./wiki/index.php?title=%E6%8E%A5%E6%94%B6%E6%99%AE%E9%80%9A%E6%B6%88%E6%81%AF

接收的消息类型有6种，分别为：

1文本消息 2图片消息 3语音消息 4视频消息 5地理位置消息 6链接消息

可以根据官方的api提供的字段建立对应的实体类

如：文本消息

有很多属性是所有消息类型都需要的，可以把这些信息提取出来建立一个基类

package com.ifp.weixin.entity.Message.req;/*** 消息基类（用户 -> 公众帐号）* */public class BaseMessage {/*** 开发者微信号*/private String ToUserName;/*** 发送方帐号（一个OpenID）*/private String FromUserName;/*** 消息创建时间 （整型）*/private long CreateTime;/*** 消息类型 text、image、location、link*/private String MsgType;/*** 消息id，64位整型*/private long 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 long getCreateTime() {return CreateTime;}public void setCreateTime(long createTime) {CreateTime = createTime;}public String getMsgType() {return MsgType;}public void setMsgType(String msgType) {MsgType = msgType;}public long getMsgId() {return MsgId;}public void setMsgId(long msgId) {MsgId = msgId;}}

接收的文本消息

package com.ifp.weixin.entity.Message.req;/*** 文本消息*/public class TextMessage extends BaseMessage {/*** 回复的消息内容*/private String Content;public String getContent() {return Content;}public void setContent(String content) {Content = content;}}

接收的图片消息

package com.ifp.weixin.entity.Message.req;public class ImageMessage extends BaseMessage{private String picUrl;public String getPicUrl() {return picUrl;}public void setPicUrl(String picUrl) {this.picUrl = picUrl;}}

接收的链接消息

package com.ifp.weixin.entity.Message.req;public class LinkMessage extends BaseMessage {/*** 消息标题*/private String Title;/*** 消息描述*/private String Description;/*** 消息链接*/private String Url;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;}}

接收的语音消息

package com.ifp.weixin.entity.Message.req;/*** 语音消息* * @author Caspar* */public class VoiceMessage extends BaseMessage {/*** 媒体ID*/private String MediaId;/*** 语音格式*/private String Format;public String getMediaId() {return MediaId;}public void setMediaId(String mediaId) {MediaId = mediaId;}public String getFormat() {return Format;}public void setFormat(String format) {Format = format;}}

接收的地理位置消息

package com.ifp.weixin.entity.Message.req;/*** 位置消息* * @author caspar* */public class LocationMessage extends BaseMessage {/*** 地理位置维度*/private String Location_X;/*** 地理位置经度*/private String Location_Y;/*** 地图缩放大小*/private String Scale;/*** 地理位置信息*/private String Label;public String getLocation_X() {return Location_X;}public void setLocation_X(String location_X) {Location_X = location_X;}public String getLocation_Y() {return Location_Y;}public void setLocation_Y(String location_Y) {Location_Y = location_Y;}public String getScale() {return Scale;}public void setScale(String scale) {Scale = scale;}public String getLabel() {return Label;}public void setLabel(String label) {Label = label;}}

发送被动响应消息

对于每一个POST请求，开发者在响应包（Get）中返回特定XML结构，对该消息进行响应（现支持回复文本、图片、图文、语音、视频、音乐）。请注意，回复图片等多媒体消息时需要预先上传多媒体文件到微信服务器，只支持认证服务号。

同样，建立响应消息的对应实体类

也把公共的属性提取出来，封装成基类

响应消息的基类

package com.ifp.weixin.entity.Message.resp;/*** 消息基类（公众帐号 -> 用户）*/public class BaseMessage {/*** 接收方帐号（收到的OpenID）*/private String ToUserName;/*** 开发者微信号*/private String FromUserName;/*** 消息创建时间 （整型）*/private long CreateTime;/*** 消息类型*/private String MsgType;/*** 位0x0001被标志时，星标刚收到的消息*/private int FuncFlag;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 long getCreateTime() {return CreateTime;}public void setCreateTime(long createTime) {CreateTime = createTime;}public String getMsgType() {return MsgType;}public void setMsgType(String msgType) {MsgType = msgType;}public int getFuncFlag() {return FuncFlag;}public void setFuncFlag(int funcFlag) {FuncFlag = funcFlag;}}

响应文本消息

package com.ifp.weixin.entity.Message.resp;/*** 文本消息*/public class TextMessage extends BaseMessage {/*** 回复的消息内容*/private String Content;public String getContent() {return Content;}public void setContent(String content) {Content = content;}}

响应图文消息

package com.ifp.weixin.entity.Message.resp;import java.util.List;/*** 多图文消息，* 单图文的时候 Articles 只放一个就行了* @author Caspar.chen*/public class NewsMessage extends BaseMessage {/*** 图文消息个数，限制为10条以内*/private int ArticleCount;/*** 多条图文消息信息，默认第一个item为大图*/private List<Article> Articles;public int getArticleCount() {return ArticleCount;}public void setArticleCount(int articleCount) {ArticleCount = articleCount;}public List<Article> getArticles() {return Articles;}public void setArticles(List<Article> articles) {Articles = articles;}}

图文消息的定义

package com.ifp.weixin.entity.Message.resp;/*** 图文消息* */public class Article {/*** 图文消息名称*/private String Title;/*** 图文消息描述*/private String Description;/*** 图片链接，支持JPG、PNG格式，<br>* 较好的效果为大图640*320，小图80*80*/private String PicUrl;/*** 点击图文消息跳转链接*/private String Url;public String getTitle() {return Title;}public void setTitle(String title) {Title = title;}public String getDescription() {return null == Description ? "" : Description;}public void setDescription(String description) {Description = description;}public String getPicUrl() {return null == PicUrl ? "" : PicUrl;}public void setPicUrl(String picUrl) {PicUrl = picUrl;}public String getUrl() {return null == Url ? "" : Url;}public void setUrl(String url) {Url = url;}}

响应音乐消息

package com.ifp.weixin.entity.Message.resp;/*** 音乐消息*/public class MusicMessage extends BaseMessage {/*** 音乐*/private Music Music;public Music getMusic() {return Music;}public void setMusic(Music music) {Music = music;}}

音乐消息的定义

package com.ifp.weixin.entity.Message.resp;/*** 音乐消息*/public class Music {/*** 音乐名称*/private String Title;/*** 音乐描述*/private String Description;/*** 音乐链接*/private String MusicUrl;/*** 高质量音乐链接，WIFI环境优先使用该链接播放音乐*/private String HQMusicUrl;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 getMusicUrl() {return MusicUrl;}public void setMusicUrl(String musicUrl) {MusicUrl = musicUrl;}public String getHQMusicUrl() {return HQMusicUrl;}public void setHQMusicUrl(String musicUrl) {HQMusicUrl = musicUrl;}}

构建好之后的项目结构图为

到这里，请求消息和响应消息的实体类都定义好了

解析请求消息

用户向微信公众平台发送消息后，微信公众平台会通过post请求发送给我们。

上一章中WeixinController 类的post方法我们空着

现在我们要在这里处理用户请求了。

因为微信的发送和接收都是用xml格式的，所以我们需要处理请求过来的xml格式。

发送的时候也需要转化成xml格式再发送给微信，所以封装了消息处理的工具类，用到dome4j和xstream两个jar包

package com.ifp.weixin.util;import java.io.InputStream;import java.io.Writer;import java.util.HashMap;import java.util.List;import java.util.Map;import javax.servlet.http.HttpServletRequest;import org.dom4j.Document;import org.dom4j.Element;import org.dom4j.io.SAXReader;import com.ifp.weixin.entity.Message.resp.Article;import com.ifp.weixin.entity.Message.resp.MusicMessage;import com.ifp.weixin.entity.Message.resp.NewsMessage;import com.ifp.weixin.entity.Message.resp.TextMessage;import com.thoughtworks.xstream.XStream;import com.thoughtworks.xstream.core.util.QuickWriter;import com.thoughtworks.xstream.io.HierarchicalStreamWriter;import com.thoughtworks.xstream.io.xml.PrettyPrintWriter;import com.thoughtworks.xstream.io.xml.XppDriver;/*** 消息工具类* */public class MessageUtil {/*** 解析微信发来的请求（XML）* * @param request* @return* @throws Exception*/public static Map<String, String> parseXml(HttpServletRequest request) throws Exception {// 将解析结果存储在HashMap中Map<String, String> map = new HashMap<String, String>();// 从request中取得输入流InputStream inputStream = request.getInputStream();// 读取输入流SAXReader reader = new SAXReader();Document document = reader.read(inputStream);// 得到xml根元素Element root = document.getRootElement();// 得到根元素的所有子节点@SuppressWarnings("unchecked")List<Element> elementList = root.elements();// 遍历所有子节点for (Element e : elementList)map.put(e.getName(), e.getText());// 释放资源inputStream.close();inputStream = null;return map;}/*** 文本消息对象转换成xml* * @param textMessage 文本消息对象* @return xml*/public static String textMessageToXml(TextMessage textMessage) {xstream.alias("xml", textMessage.getClass());return xstream.toXML(textMessage);}/*** 音乐消息对象转换成xml* * @param musicMessage 音乐消息对象* @return xml*/public static String musicMessageToXml(MusicMessage musicMessage) {xstream.alias("xml", musicMessage.getClass());return xstream.toXML(musicMessage);}/*** 图文消息对象转换成xml* * @param newsMessage 图文消息对象* @return xml*/public static String newsMessageToXml(NewsMessage newsMessage) {xstream.alias("xml", newsMessage.getClass());xstream.alias("item", new Article().getClass());return xstream.toXML(newsMessage);}/*** 扩展xstream，使其支持CDATA块* */private static XStream xstream = new XStream(new XppDriver() {public HierarchicalStreamWriter createWriter(Writer out) {return new PrettyPrintWriter(out) {// 对所有xml节点的转换都增加CDATA标记boolean cdata = true;protected void writeText(QuickWriter writer, String text) {if (cdata) {writer.write("<![CDATA[");writer.write(text);writer.write("]]>");} else {writer.write(text);}}};}});}

接下来在处理业务逻辑，建立一个接收并响应消息的service类，并针对用户输入的1或2回复不同的信息给用户

package com.ifp.weixin.biz.core.impl;import java.util.Date;import java.util.Map;import javax.servlet.http.HttpServletRequest;import org.apache.log4j.Logger;import org.springframework.stereotype.Service;import com.ifp.weixin.biz.core.CoreService;import com.ifp.weixin.constant.Constant;import com.ifp.weixin.entity.Message.resp.TextMessage;import com.ifp.weixin.util.MessageUtil;@Service("coreService")public class CoreServiceImpl implements CoreService{public static Logger log = Logger.getLogger(CoreServiceImpl.class);@Overridepublic String processRequest(HttpServletRequest request) {String respMessage = null;try {// xml请求解析Map<String, String> requestMap = MessageUtil.parseXml(request);// 发送方帐号（open_id）String fromUserName = requestMap.get("FromUserName");// 公众帐号String toUserName = requestMap.get("ToUserName");// 消息类型String msgType = requestMap.get("MsgType");TextMessage textMessage = new TextMessage();textMessage.setToUserName(fromUserName);textMessage.setFromUserName(toUserName);textMessage.setCreateTime(new Date().getTime());textMessage.setMsgType(Constant.RESP_MESSAGE_TYPE_TEXT);textMessage.setFuncFlag(0);// 文本消息if (msgType.equals(Constant.REQ_MESSAGE_TYPE_TEXT)) {// 接收用户发送的文本消息内容String content = requestMap.get("Content");if ("1".equals(content)) {textMessage.setContent("1是很好的");// 将文本消息对象转换成xml字符串respMessage = MessageUtil.textMessageToXml(textMessage);}else if ("2".equals(content)) {textMessage.setContent("我不是2货");// 将文本消息对象转换成xml字符串respMessage = MessageUtil.textMessageToXml(textMessage);}} } catch (Exception e) {e.printStackTrace();}return respMessage;}}

接下来在controller里面的post方法里面调用即可

WeixinController类的完整代码

package com.ifp.weixin.controller;import java.io.IOException;import java.io.PrintWriter;import java.io.UnsupportedEncodingException;import javax.annotation.Resource;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import com.ifp.weixin.biz.core.CoreService;import com.ifp.weixin.util.SignUtil;@Controller@RequestMapping("/weixinCore")public class WeixinController {@Resource(name="coreService")private CoreService coreService;@RequestMapping(method = RequestMethod.GET)public void get(HttpServletRequest request, HttpServletResponse response) {// 微信加密签名，signature结合了开发者填写的token参数和请求中的timestamp参数、nonce参数。String signature = request.getParameter("signature");// 时间戳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 = null;try {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，否则接入失败if (SignUtil.checkSignature(signature, timestamp, nonce)) {out.print(echostr);}} catch (IOException e) {e.printStackTrace();} finally {out.close();out = null;}}@RequestMapping(method = RequestMethod.POST)public void post(HttpServletRequest request, HttpServletResponse response) {try {request.setCharacterEncoding("UTF-8");} catch (UnsupportedEncodingException e) {e.printStackTrace();}response.setCharacterEncoding("UTF-8");// 调用核心业务类接收消息、处理消息String respMessage = coreService.processRequest(request);// 响应消息PrintWriter out = null;try {out = response.getWriter();out.print(respMessage);} catch (IOException e) {e.printStackTrace();} finally {out.close();out = null;}}}

效果如下：

ok，大功告成，消息的接收和发送就写完了。

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