微信公众平台开发学习记录(3)————接收消息和发送回复消息

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。

当用户发送消息给公众号时（或某些特定的用户操作引发的事件推送时），会产生一个POST请求，开发者可以在响应包（Get）中返回特定XML结构，来对该消息进行响应（现支持回复文本、图片、图文、语音、视频、音乐）。严格来说，发送被动响应消息其实并不是一种接口，而是对微信服务器发过来消息的一次回复。回复消息是根据接收的xml中获取到用户信息，根据各类型消息XML结构示例进行拼接。

代码：

package com.qs.action;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.Date;

import javax.servlet.ServletInputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.struts2.interceptor.ServletRequestAware;
import org.apache.struts2.interceptor.ServletResponseAware;

import com.opensymphony.xwork2.ActionSupport;
import com.qs.util.SignUtil;

/**
* @author qiaoshuai
* @createDate 2016-3-1
*/
public class TestWeiXinAction extends ActionSupport implements
ServletRequestAware, ServletResponseAware {

private static final long serialVersionUID = -799327593656049028L;
protected HttpServletRequest request;
private HttpServletResponse response;

public void setServletResponse(HttpServletResponse response) {
this.response = response;
}

public void setServletRequest(HttpServletRequest request) {
this.request = request;
}

public void checkSignature() throws IOException {
boolean isGet = request.getMethod().toLowerCase().equals("get");
if (isGet) {
// 微信加密签名
String signature = request.getParameter("signature");
System.out.println("signature=" + signature);
// 时间戳
String timestamp = request.getParameter("timestamp");
System.out.println("timestamp=" + timestamp);
// 随机数
String nonce = request.getParameter("nonce");
System.out.println("nonce=" + nonce);
// 随机字符串
String echostr = request.getParameter("echostr");
System.out.println("echostr=" + echostr);
PrintWriter 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，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;
} else {
// POST
responseMsg();
}

}

public void responseMsg() throws  IOException{
String outString = "";
String replyString = "";
BufferedReader br = new BufferedReader(new InputStreamReader(
(ServletInputStream) request.getInputStream(), "utf-8"));
String line = null;
StringBuilder sb = new StringBuilder();
while ((line = br.readLine()) != null) {
sb.append(line);
}
String xmlS = sb.toString();
System.out.println(xmlS);

if (xmlS != null && !xmlS.equals("")) {
// 用户发送者
int fromuser_s = xmlS.indexOf("<FromUserName><![CDATA[");
int fromuser_e = xmlS.indexOf("]]></FromUserName>");
String fromuser = xmlS.substring(fromuser_s + 23, fromuser_e);
System.out.println("fromuser:" + fromuser);

// 取出目标用户
int touser_s = xmlS.indexOf("<ToUserName><![CDATA[");
int touser_e = xmlS.indexOf("]]></ToUserName>");
String touser = xmlS.substring(touser_s + 21, touser_e);
System.out.println("touser:" + touser);

// 获取请求类型
int msgType_s = xmlS.indexOf("<MsgType><![CDATA[");
int msgType_e = xmlS.indexOf("]]></MsgType>");
String msgType = xmlS.substring(msgType_s + 18, msgType_e);
System.out.println("msgType:" + msgType);

// 获取请求当前时间
int createTime_s = xmlS.indexOf("<CreateTime>");
int createTime_e = xmlS.indexOf("</CreateTime>");
String createTime = xmlS.substring(createTime_s + 12, createTime_e);
int createTimeInt = Integer.parseInt(createTime);
System.out.println("createTime:" + createTimeInt);

// 接收点击推事件消息
if ("event".equals(msgType)) {
StringBuilder outBuilder = new StringBuilder();
int EventKey_s = xmlS.indexOf("<EventKey><![CDATA[");
int EventKey_e = xmlS.indexOf("]]></EventKey>");
String eventKey = xmlS.substring(EventKey_s + 19, EventKey_e);
System.out.println("EventKey:" + eventKey);
if (eventKey.equals("V1001_TODAY_MUSIC")) { //

outBuilder.append("《燕归巢》");
outString = textDemo(outBuilder.toString());
}else if(eventKey.equals("V1001_GOOD")){
outBuilder.append("谢谢您的赞！");
outString = textDemo(outBuilder.toString());
}
}

// 接收文本消息
if ("text".equals(msgType)) {
StringBuilder outBuilder = new StringBuilder();
int content_s = xmlS.indexOf("<Content><![CDATA[");
int content_e = xmlS.indexOf("]]></Content>");
String content = xmlS.substring(content_s + 18, content_e);
System.out.println("content:" + content);
if (content.equals("天气")) { // 帮助回复（文本回复）

outBuilder.append("今天是晴天");
outString = textDemo(outBuilder.toString());
}else{
outBuilder.append(content + "啊哈");
outString = textDemo(outBuilder.toString());
}

}

//
replyString = this.replyDemo(fromuser, touser, outString);
}
System.out.println("replyString:" + replyString);
this.print(replyString);

}

// 向请求端发送返回数据
public void print(String content) {
try {
response.setContentType("text/html;charset=utf-8");
response.getWriter().print(content);
response.getWriter().flush();
response.getWriter().close();
} catch (Exception e) {
e.printStackTrace();
}
}

public String replyDemo(String fromuser, String touser, String content) {
StringBuilder outString = new StringBuilder();
// 表头
outString.append("<xml>");
outString.append("    <ToUserName><![CDATA[" + fromuser
+ "]]></ToUserName>");
outString.append("    <FromUserName><![CDATA[" + touser
+ "]]></FromUserName>");
outString.append("    <CreateTime>" + new Date().getTime()
+ "</CreateTime>");
// 表中
outString.append(content);
// 表尾
outString.append("    <FuncFlag>0</FuncFlag>");
outString.append("</xml>");
return outString.toString();
}

/**
*文本回复 Demo
*
* @param content
*            字符串内容
**/
public String textDemo(String content) {
StringBuilder textString = new StringBuilder();
textString.append("<MsgType><![CDATA[text]]></MsgType>");
textString.append("<Content><![CDATA[").append(content).append(
"]]></Content>");
return textString.toString();
}

/**
*图文回复 Demo
*
* @param title
*            标题
* @param description
*            简介内容
* @param picUrl
*            图片路径
* @param skipUrl
*            链接路径
*
**/
public String textPicDemo(String title, String description, String picUrl,
String skipUrl) {
StringBuilder textPicString = new StringBuilder();
textPicString.append("  <MsgType><![CDATA[news]]></MsgType>");
textPicString.append("  <ArticleCount>1</ArticleCount>");
textPicString.append("  <Articles>");
textPicString.append("    <item>");
textPicString.append("      <Title><![CDATA[" + title + "]]></Title> ");
if (description != null) {
textPicString.append("      <Description><![CDATA[" + description
+ "]]></Description>");
}
textPicString
.append("	    <PicUrl><![CDATA[" + picUrl + "]]></PicUrl>");
textPicString.append("      <Url><![CDATA[" + skipUrl + "]]></Url>");
textPicString.append("    </item>");
textPicString.append("  </Articles>");
return textPicString.toString();
}

/**
* 多张图文回复 Demo
*
* @param articleCount
*            图文数量
* @param content
*            图文内容
**/
public String textPicListDemosun(String[] titles, String[] descriptions,
String[] picUrls, String[] skipUrls) {
StringBuilder textPicString = new StringBuilder();
textPicString.append("  <MsgType><![CDATA[news]]></MsgType>");
textPicString.append("  <ArticleCount>" + 1 + "</ArticleCount>");
textPicString.append("  <Articles>");
textPicString.append("    <item>");
textPicString.append("      <Title><![CDATA[" + titles[0]
+ "]]></Title> ");
if (descriptions != null) {
textPicString.append("      <Description><![CDATA["
+ descriptions[0] + "]]></Description>");
}
textPicString.append("	    <PicUrl><![CDATA[" + picUrls[0]
+ "]]></PicUrl>");
textPicString
.append("      <Url><![CDATA[" + skipUrls[0] + "]]></Url>");
textPicString.append("    </item>");
textPicString.append("  </Articles>");
return textPicString.toString();
}

/**
* 多张图文回复 Demo
*
* @param articleCount
*            图文数量
* @param content
*            图文内容
**/
public String textPicListDemo(int articleCount, String content) {
StringBuilder textPicString = new StringBuilder();
textPicString.append("  <MsgType><![CDATA[news]]></MsgType>");
textPicString.append("  <ArticleCount>" + articleCount
+ "</ArticleCount>");
textPicString.append("  <Articles>");
textPicString.append(content);
textPicString.append("  </Articles>");
return textPicString.toString();
}

}

效果：