Java微信二次开发（二）

第二天，做微信文本消息接口请求与发送

需要导入库：dom4j-1.6.1.jar，xstream-1.3.1.jar

第一步：新建包com.wtz.message.response，新建类BaseMessage.java

 package com.wtz.message.response;

 /**
  *     @author wangtianze QQ:864620012
  *    @date 2017年4月19日 下午3:12:40
  *  <p>version:1.0</p>
  *     <p>description:基础消息类</p>
  */
 public class BaseMessage {
     //接收方
     private String ToUserName;
     //发送方
     private String FromUserName;
     //消息的创建时间
     private long CreateTime;
     //消息类型
     private String MsgType;

     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;
     }
 }

第二步：找到包com.wtz.message.response，新建类TextMessage.java

 package com.wtz.message.response;

 /**
  *     @author wangtianze QQ:864620012
  *    @date 2017年4月19日 下午3:22:33
  *  <p>version:1.0</p>
  *     <p>description:文本消息类</p>
  */
 public class TextMessage extends BaseMessage{
     //消息内容
     private String Content;

     public String getContent() {
         return Content;
     }
     public void setContent(String content) {
         Content = content;
     }
 }

第三步：找到包com.wtz.util，新建类MessageUtil.java

 package com.wtz.util;

 import java.io.IOException;
 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.DocumentException;
 import org.dom4j.Element;
 import org.dom4j.io.SAXReader;

 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;
 import com.wtz.message.response.TextMessage;

 /**
  *     @author wangtianze QQ:864620012
  *    @date 2017年4月19日 下午3:29:58
  *  <p>version:1.0</p>
  *     <p>description:消息处理工具类</p>
  */
 public class MessageUtil {
     //定义了消息类型（常量：文本类型）
     public static final String RESP_MESSAGE_TYPE_TEXT = "text";

     //从流中解析出每个节点的内容
     public static Map<String,String> parseXml(HttpServletRequest request) throws IOException{
         Map<String,String> map = new HashMap<String,String>();

         //从输入流中获取流对象
         InputStream in = request.getInputStream();

         //构建SAX阅读器对象
         SAXReader reader = new SAXReader();
         try {
             //从流中获得文档对象
             Document doc = reader.read(in);

             //获得根节点
             Element root = doc.getRootElement();

             //获取根节点下的所有子节点
             List<Element> children = root.elements();

             for(Element e:children){
                 //遍历每一个节点，并按照节点名--节点值放入map中
                 map.put(e.getName(), e.getText());
                 System.out.println("用户发送的消息XML解析为：" + e.getName() + e.getText());
             }

             //关闭流
             in.close();
             in = null;
         } catch (DocumentException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
         }

         return map;
     }

     /**
      * 用于扩展节点数据按照<ToUserName><![CDATA[toUser]]></ToUserName>，中间加了CDATA段
      */
     private static XStream xstream = new XStream(new XppDriver(){
         public HierarchicalStreamWriter createWriter(Writer out){
             return new PrettyPrintWriter(out){
                 boolean cdata = true;
                 public void startNode(String name,Class clazz){
                     super.startNode(name,clazz);
                 }

                 protected void writeText(QuickWriter writer,String text){
                     if(cdata){
                         writer.write("<![CDATA[");
                         writer.write(text);
                         writer.write("]]>");
                     }else{
                         writer.write(text);
                     }
                 }
             };
         }
     });

     /**
      * 将文本消息转换成XML格式
      */
     public static String messageToXml(TextMessage textMessage){
         xstream.alias("xml",textMessage.getClass());
         String xml = xstream.toXML(textMessage);
         System.out.println("响应所转换的XML："+xml);
         return xml;
     }
 }

第四步：找到包com.wtz.service，新建类ProcessService.java

 package com.wtz.util;

 import java.io.IOException;
 import java.util.Date;
 import java.util.Map;

 import javax.servlet.http.HttpServletRequest;

 import com.wtz.message.response.TextMessage;

 /**
  *     @author wangtianze QQ:864620012
  *    @date 2017年4月19日 下午8:04:14
  *  <p>version:1.0</p>
  *     <p>description:核心服务类</p>
  */
 public class ProcessService {
     public static String dealRequest(HttpServletRequest request) throws IOException{
         //响应的XML串
         String respXml = "";

         //要响应的文本内容
         String respContent = "未知的消息类型";
         Map<String,String> requestMap = MessageUtil.parseXml(request);
         String fromUserName = requestMap.get("FromUserName");
         String toUserName = requestMap.get("ToUserName");
         String MsgType = requestMap.get("MsgType");
         String Content = requestMap.get("Content");

         System.out.println("用户给公众号发的消息为：" + Content);

         //构建一条文本消息
         TextMessage textMessage = new TextMessage();
         textMessage.setToUserName(fromUserName);
         textMessage.setFromUserName(toUserName);
         textMessage.setCreateTime(new Date().getTime());
         textMessage.setMsgType(MessageUtil.RESP_MESSAGE_TYPE_TEXT);

         if(MsgType.equals(MessageUtil.RESP_MESSAGE_TYPE_TEXT)){
             respContent = "王天泽的公众号收到了您的一条文本消息：" + Content + "，时间戳是：" + (new Date().getTime());
         }
         textMessage.setContent(respContent);
         respXml = MessageUtil.messageToXml(textMessage);

         System.out.println("respXml:"+respXml);

         return respXml;
     }
 }

第五步：找到包com.wtz.service下的LoginServlet类，重写doPost方法

 package com.wtz.service;

 import java.io.IOException;
 import java.io.PrintWriter;

 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServlet;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;

 import com.wtz.util.MessageUtil;
 import com.wtz.util.ProcessService;
 import com.wtz.util.ValidationUtil;

 /**
  *     @author wangtianze QQ:864620012
  *    @date 2017年4月17日 下午8:11:32
  *  <p>version:1.0</p>
  *     <p>description:微信请求验证类</p>
  */
 public class LoginServlet extends HttpServlet {

     @Override
     protected void doGet(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException {
         System.out.println("get请求。。。。。。");

         //1.获得微信签名的加密字符串
         String signature = request.getParameter("signature");

         //2.获得时间戳信息
         String timestamp = request.getParameter("timestamp");

         //3.获得随机数
         String nonce = request.getParameter("nonce");

         //4.获得随机字符串
         String echostr = request.getParameter("echostr");

         System.out.println("获得微信签名的加密字符串："+signature);
         System.out.println("获得时间戳信息："+timestamp);
         System.out.println("获得随机数："+nonce);
         System.out.println("获得随机字符串："+echostr);

         PrintWriter out = response.getWriter();

         //验证请求确认成功原样返回echostr参数内容，则接入生效，成为开发者成功，否则失败
         if(ValidationUtil.checkSignature(signature, timestamp, nonce)){
             out.print(echostr);
         }

         out.close();
         out = null;
     }

     /**
      * 接受微信服务器发过来的XML数据包（通过post请求发送过来的）
      */
     @Override
     protected void doPost(HttpServletRequest request, HttpServletResponse response)
             throws ServletException, IOException {

         request.setCharacterEncoding("utf-8");
         response.setCharacterEncoding("utf-8");

         //获取微信加密的签名字符串
         String signature = request.getParameter("signature");

         //获取时间戳
         String timestamp = request.getParameter("timestamp");

         //获取随机数
         String nonce = request.getParameter("nonce");

         PrintWriter out = response.getWriter();

         if(ValidationUtil.checkSignature(signature,timestamp,nonce)){
             String respXml = "";
             try {
                 respXml = ProcessService.dealRequest(request);
             } catch (Exception e) {
                 // TODO Auto-generated catch block
                 e.printStackTrace();
             }
             out.print(respXml);
         }
         out.close();
         out = null;
     }
 }

完成微信文本消息接口请求与发送。