微信开发之处理微信客户端发来的消息

在上一篇微信开发的博文中微信开发(01)之如何成为开发者，我们开启了微信开发者模式，本篇博文我们简单的处理微信关注者发给我们公众号的消息。

在开启微信开发者模式时，我们配置了一个URL地址，当我们提交开启微信开发者模式，腾讯的微信服务器会向该URL地址发送一个get请求，并且携带一些参数，让我们来验证。说到get请求，就必须说到post请求，关注我们公众号的微信粉丝发来的消息，触发的事件，腾讯的微信服务器则会像该URL地址发送一个post请求，请求的内容就是以xml文档形式的字符串。

所以该URL地址的get请求的处理方法，专门用于开启微信开发者模式；而post请求则用于处理微信粉丝发给我们的消息，或者触发的事件，所以我们后面的微信开发工作的起点就是该URL地址的post处理方法。

下面我们处理一个最简单的例子：粉丝发送任意一个文本信息给我们，我们给他回复一个消息：“你好，+ 他微信的openId”

下面直接贴代码：

URL对应的处理servlet:

public class CoreServlet extends HttpServlet {private static final long serialVersionUID = 4440739483644821986L;/** * 请求校验（确认请求来自微信服务器） */public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// 微信服务端发来的加密签名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 = response.getWriter();// 请求校验，若校验成功则原样返回echostr，表示接入成功，否则接入失败if (SignUtil.checkSignature(signature, timestamp, nonce)) {out.print(echostr);}out.close();out = null;}/** * 请求校验与处理 */public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {// 将请求、响应的编码均设置为UTF-8（防止中文乱码）request.setCharacterEncoding("UTF-8");response.setCharacterEncoding("UTF-8");// 接收参数微信加密签名、 时间戳、随机数String signature = request.getParameter("signature");String timestamp = request.getParameter("timestamp");String nonce = request.getParameter("nonce");PrintWriter out = response.getWriter();// 请求校验if (SignUtil.checkSignature(signature, timestamp, nonce)) {Message msgObj = XMLUtil.getMessageObject(request);// 读取微信客户端发来的消息(xml字符串)，并将其转换为消息对象if(msgObj != null){String xml = "<xml>" + "<ToUserName><![CDATA[" + msgObj.getFromUserName() + "]]></ToUserName>" +// 接收方帐号（收到的OpenID） "<FromUserName><![CDATA[" + msgObj.getToUserName() + "]]></FromUserName>" +// 开发者微信号 "<CreateTime>12345678</CreateTime>" + "<MsgType><![CDATA[text]]></MsgType>" + "<Content><![CDATA[你好，"+ msgObj.getFromUserName() +"]]></Content>" + "</xml>";out.write(xml);// 回复微信客户端的消息(xml字符串)out.close();return;}}out.write("");out.close();}}

xml字符串的处理工具类，实现xml消息到消息对象的转换：

public class XMLUtil {/** * 从request中读取用户发给公众号的消息内容 * @param request * @return 用户发给公众号的消息内容 * @throws IOException */public static String readRequestContent(HttpServletRequest request) throws IOException{// 从输入流读取返回内容InputStream inputStream = request.getInputStream();InputStreamReader inputStreamReader = new InputStreamReader(inputStream, "utf-8");BufferedReader bufferedReader = new BufferedReader(inputStreamReader);String str = null;StringBuilder buffer = new StringBuilder();while ((str = bufferedReader.readLine()) != null) {buffer.append(str);}// 释放资源bufferedReader.close();inputStreamReader.close();inputStream.close();return buffer.toString();}/** * 将xml文档的内容转换成map * @param xmlDoc * @return map */public static Map<String, String> xmlToMap(String xmlDoc){//创建一个新的字符串StringReader read = new StringReader(xmlDoc);//创建新的输入源SAX 解析器将使用 InputSource 对象来确定如何读取 XML 输入InputSource source = new InputSource(read);//创建一个新的SAXBuilderSAXBuilder sb = new SAXBuilder();Map<String, String> xmlMap = new HashMap<String, String>();try {Document doc = sb.build(source);//通过输入源构造一个DocumentElement root = doc.getRootElement();//取的根元素List<Element> cNodes = root.getChildren();//得到根元素所有子元素的集合(根元素的子节点，不包括孙子节点)Element et = null;for(int i=0;i<cNodes.size();i++){et = (Element) cNodes.get(i);//循环依次得到子元素xmlMap.put(et.getName(), et.getText());}} catch (JDOMException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();}return xmlMap;}/** * 将保存xml内容的map转换成对象 * @param map * @return */public static Message getMessageObject(Map<String, String> map){if(map != null){String MsgType = map.get("MsgType");// 消息类型(文本消息:text, 图片消息:image, 语音消息:voice, 视频消息:video, // 地理位置消息:location, 链接消息:link)if("text".equals(MsgType)){TextMessage msg = new TextMessage();XMLUtil.initCommonMsg(msg, map);msg.setContent(map.get("Content"));return msg;}if("ImageMessage".equals(MsgType)){ImageMessage msg = new ImageMessage();XMLUtil.initCommonMsg(msg, map);msg.setPicUrl(map.get("PicUrl"));msg.setMediaId(map.get("MediaId"));return msg;}if("video".equals(MsgType)){VideoMessage msg = new VideoMessage();XMLUtil.initCommonMsg(msg, map);msg.setMediaId(map.get("MediaId"));msg.setThumbMediaId(map.get("ThumbMediaId"));return msg;}if("voice".equals(MsgType)){VoiceMessage msg = new VoiceMessage();XMLUtil.initCommonMsg(msg, map);msg.setMediaId(map.get("MediaId"));msg.setFormat(map.get("Format"));return msg;}if("location".equals(MsgType)){LocationMessage msg = new LocationMessage();msg.setLocation_X(map.get("Location_X"));msg.setLocation_Y(map.get("Location_Y"));msg.setScale(map.get("Scale"));msg.setLabel(map.get("Label"));return msg;}if("link".equals(MsgType)){LinkMessage msg = new LinkMessage();XMLUtil.initCommonMsg(msg, map);msg.setTitle(map.get("Title"));msg.setDescription(map.get("Description"));msg.setUrl(map.get("Url"));return msg;}}return null;}/** * 将保存xml内容的map转换成对象 * @param map * @return * @throws IOException*/public static Message getMessageObject(HttpServletRequest request) throws IOException{String xmlDoc = XMLUtil.readRequestContent(request);// 读取微信客户端发了的消息(xml)Map<String, String> map = XMLUtil.xmlToMap(xmlDoc);// 将客户端发来的xml转换成Mapif(map != null){String MsgType = map.get("MsgType");// 消息类型(文本消息:text, 图片消息:image, 语音消息:voice, 视频消息:video, // 地理位置消息:location, 链接消息:link)if("text".equals(MsgType)){TextMessage msg = new TextMessage();XMLUtil.initCommonMsg(msg, map);msg.setContent(map.get("Content"));return msg;}/*if("ImageMessage".equals(MsgType)){ImageMessage msg = new ImageMessage();XMLUtil.initCommonMsg(msg, map);msg.setPicUrl(map.get("PicUrl"));msg.setMediaId(map.get("MediaId"));return msg;}if("video".equals(MsgType)){VideoMessage msg = new VideoMessage();XMLUtil.initCommonMsg(msg, map);msg.setMediaId(map.get("MediaId"));msg.setThumbMediaId(map.get("ThumbMediaId"));return msg;}if("voice".equals(MsgType)){VoiceMessage msg = new VoiceMessage();XMLUtil.initCommonMsg(msg, map);msg.setMediaId(map.get("MediaId"));msg.setFormat(map.get("Format"));return msg;}if("location".equals(MsgType)){LocationMessage msg = new LocationMessage();msg.setLocation_X(map.get("Location_X"));msg.setLocation_Y(map.get("Location_Y"));msg.setScale(map.get("Scale"));msg.setLabel(map.get("Label"));return msg;}if("link".equals(MsgType)){LinkMessage msg = new LinkMessage();XMLUtil.initCommonMsg(msg, map);msg.setTitle(map.get("Title"));msg.setDescription(map.get("Description"));msg.setUrl(map.get("Url"));return msg;}*/}return null;}public static void initCommonMsg(Message msg, Map<String, String> map){msg.setMsgId(map.get("MsgId"));msg.setMsgType(map.get("MsgType"));msg.setToUserName(map.get("ToUserName"));msg.setFromUserName(map.get("FromUserName"));msg.setCreateTime(map.get("CreateTime"));}}

粉丝发来的消息分为了6中类型(文本消息, 图片消息, 语音消息, 视频消息, 地理位置消息, 链接消息)：

/** * 微信消息基类 * @author yuanfang * @date 2015-03-23 */public class Message {private String MsgId;// 消息id，64位整型private String MsgType;// 消息类型(文本消息:text, 图片消息:image, 语音消息:voice, 视频消息:video, 地理位置消息:location, 链接消息:link)private String ToUserName;//开发者微信号private String FromUserName; // 发送方帐号（一个OpenID）private String CreateTime;// 消息创建时间 （整型）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;}public String getMsgId() {return MsgId;}public void setMsgId(String msgId) {MsgId = msgId;}}

文本消息类：

package com.sinaapp.wx.msg;public class TextMessage extends Message {private String Content;// 文本消息内容public String getContent() {return Content;}public void setContent(String content) {Content = content;}}

OK，对粉丝发送给我们公众号的任意的文本消息的最简单处理就完成，我们简单的回复他：你好，然后加上他微信的openId，类似于：你好，orJydljfkg3-r0_dj3rkdfvjl

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