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。