In the previous article "WeChat Development—WeChat Development Environment Construction" we have completed the preparations for WeChat development. After the preparations are completed, we will start to get down to business.

1. The basic principles of WeChat public platform

Before starting, let’s briefly introduce the basic principles of WeChat public platform.

The WeChat server is equivalent to a forwarding server. The terminal (mobile phone, Pad, etc.) initiates a request to the WeChat server, and the WeChat server then forwards the request to our application server. After the application server completes processing, it sends the response data back to the WeChat server, and the WeChat server then replies the specific response information to the WeChat App terminal.

The communication protocol is: HTTP

The data transmission format is: XML

The specific process is as shown in the figure below:

Let’s get a more intuitive picture:

What we need to do is to respond to the HTTP request forwarded by the WeChat server. We parse the specific request content according to a specific XML format. After processing, we must also return it according to a specific XML format.

2. WeChat public account access

In the WeChat public platform developer documentation, the section on public account access is written in more detail in the access guide. In the document It is said that accessing the official account requires three steps, which are:

　1. Fill in the server configuration
　2. Verify the validity of the server address
　3. Implement business logic based on the interface document

In fact, step 3 can no longer be regarded as the step of connecting the official account, but after the connection, developers can do some development based on the interface provided by the WeChat official account.

The server configuration in step 1 includes server address (URL), Token and EncodingAESKey.

The server address is the entry address for the business logic provided by the public account backend. Currently, it only supports port 80. It will later include access verification and any other operation requests (such as message sending, menu management, material management, etc.) You must enter from this address. The difference between access verification and other requests is that access verification is a get request, and other times it is a post request;

Token can be filled in by the developer arbitrarily and used to generate a signature (the Token will be the same as the one in the interface URL The included Token is compared to verify security);

The EncodingAESKey is manually filled in by the developer or randomly generated, and will be used as the message body encryption and decryption key. In this example, all messages are in unencrypted plain text, and this configuration item is not involved.

Step 2, verify the validity of the server address. When the "Submit" button is clicked, the WeChat server will send an http get request to the server address just filled in, and carry four Parameters:

After receiving the request, we need to do the following three steps. If it is confirmed that the GET request comes from the WeChat server, the If the content of the echostr parameter is returned, the access will take effect, otherwise the access will fail.

1. Sort the three parameters token, timestamp, and nonce in lexicographic order
2. Splice the three parameter strings into one string for sha1 encryption
3. After the developer obtains the encryption The string can be compared with signature to indicate that the request comes from WeChat

Let’s use Java code to demonstrate this verification process

Use IDE (Eclipse or IntelliJ IDEA) to create a JavaWeb project. Here I am using IntelliJ IDEA. The project directory structure is as shown below:

Write a servlevt and define the verification method in the doGet method. The specific code is as follows:

package me.gacl.wx.web.servlet;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;

/**
 * Created by xdp on 2016/1/25.
 * 使用@WebServlet注解配置WxServlet,urlPatterns屬性指明了WxServlet的訪問路徑
 */
@WebServlet(urlPatterns="/WxServlet")
public class WxServlet extends HttpServlet {

    /**
     * Token可由開發(fā)者可以任意填寫，用作生成簽名（該Token會(huì)和接口URL中包含的Token進(jìn)行比對(duì)，從而驗(yàn)證安全性）
     * 比如這里我將Token設(shè)置為gacl
     */
    private final String TOKEN = "gacl";

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        System.out.println("開始校驗(yàn)簽名");
        /**
         * 接收微信服務(wù)器發(fā)送請(qǐng)求時(shí)傳遞過來的4個(gè)參數(shù)
         */
        String signature = request.getParameter("signature");//微信加密簽名signature結(jié)合了開發(fā)者填寫的token參數(shù)和請(qǐng)求中的timestamp參數(shù)、nonce參數(shù)。
        String timestamp = request.getParameter("timestamp");//時(shí)間戳
        String nonce = request.getParameter("nonce");//隨機(jī)數(shù)
        String echostr = request.getParameter("echostr");//隨機(jī)字符串
        //排序
        String sortString = sort(TOKEN, timestamp, nonce);
        //加密
        String mySignature = sha1(sortString);
        //校驗(yàn)簽名
        if (mySignature != null && mySignature != "" && mySignature.equals(signature)) {
            System.out.println("簽名校驗(yàn)通過。");
            //如果檢驗(yàn)成功輸出echostr，微信服務(wù)器接收到此輸出，才會(huì)確認(rèn)檢驗(yàn)完成。
            //response.getWriter().println(echostr);
            response.getWriter().write(echostr);
        } else {
            System.out.println("簽名校驗(yàn)失敗.");
        }

    }

    /**
     * 排序方法
     *
     * @param token
     * @param timestamp
     * @param nonce
     * @return
     */
    public String sort(String token, String timestamp, String nonce) {
        String[] strArray = {token, timestamp, nonce};
        Arrays.sort(strArray);
        StringBuilder sb = new StringBuilder();
        for (String str : strArray) {
            sb.append(str);
        }

        return sb.toString();
    }

    /**
     * 將字符串進(jìn)行sha1加密
     *
     * @param str 需要加密的字符串
     * @return 加密后的內(nèi)容
     */
    public String sha1(String str) {
        try {
            MessageDigest digest = MessageDigest.getInstance("SHA-1");
            digest.update(str.getBytes());
            byte messageDigest[] = digest.digest();
            // Create Hex String
            StringBuffer hexString = new StringBuffer();
            // 字節(jié)數(shù)組轉(zhuǎn)換為 十六進(jìn)制 數(shù)
            for (int i = 0; i < messageDigest.length; i++) {
                String shaHex = Integer.toHexString(messageDigest[i] & 0xFF);
                if (shaHex.length() < 2) {
                    hexString.append(0);
                }
                hexString.append(shaHex);
            }
            return hexString.toString();

        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        }
        return "";
    }
}

I use Servlet3.0 here. The advantage of using Servlet3.0 is that you can directly use the @WebServlet annotation to map the access path of the Servlet. You no longer need to do it in the web.xml file. Configuration.

Deploy the WxStudy project to the Tomcat server, start the project directly, and then use ngrok to map the local 8080 port to the external network (for how to use ngrok, please refer to the blog "WeChat Development—WeChat Development Environment Construction") . As shown below:

　　測(cè)試是否可以通過http://xdp.ngrok.natapp.cn地址正常訪問，測(cè)試結(jié)果如下：

　　可以看到，我們的項(xiàng)目已經(jīng)可以被外網(wǎng)正常訪問到了。

　　進(jìn)入微信測(cè)試公眾號(hào)管理界面，在接口配置信息中填入映射的外網(wǎng)地址和token，如下圖所示：

　　點(diǎn)擊提交按鈕，頁(yè)面會(huì)提示配置成功，

　　IDE的控制臺(tái)中輸出了校驗(yàn)通過的信息,如下圖所示:

　　到此，我們的公眾號(hào)應(yīng)用已經(jīng)能夠和微信服務(wù)器正常通信了，也就是說我們的公眾號(hào)已經(jīng)接入到微信公眾平臺(tái)了。

三、access_token管理

3.1、access_token介紹

　　我們的公眾號(hào)和微信服務(wù)器對(duì)接成功之后，接下來要做的就是根據(jù)我們的業(yè)務(wù)需求調(diào)用微信公眾號(hào)提供的接口來實(shí)現(xiàn)相應(yīng)的邏輯了。在使用微信公眾號(hào)接口中都需要一個(gè)access_token。

　　關(guān)于access_token，在微信公眾平臺(tái)開發(fā)者文檔上的獲取接口調(diào)用憑據(jù)有比較詳細(xì)的介紹：access_token是公眾號(hào)的全局唯一票據(jù)，公眾號(hào)調(diào)用各接口時(shí)都需使用access_token，開發(fā)者需要妥善保存access_token的存儲(chǔ)至少要保留512個(gè)字符空間。access_token的有效期目前為2個(gè)小時(shí)，需定時(shí)刷新，重復(fù)獲取將導(dǎo)致上次獲取的access_token失效。并且每天調(diào)用獲取access_token接口的上限是2000次。

　　總結(jié)以上說明，access_token需要做到以下兩點(diǎn)：

　　1.因?yàn)閍ccess_token有2個(gè)小時(shí)的時(shí)效性，要有一個(gè)機(jī)制保證最長(zhǎng)2個(gè)小時(shí)重新獲取一次。

　　2.因?yàn)榻涌谡{(diào)用上限每天2000次，所以不能調(diào)用太頻繁。

3.2、微信公眾平臺(tái)提供的獲取access_token的接口

　　關(guān)于access_token的獲取方式，在微信公眾平臺(tái)開發(fā)者文檔上有說明，公眾號(hào)可以調(diào)用一個(gè)叫"獲取access token"的接口來獲取access_token。

　　獲取access token接口調(diào)用請(qǐng)求說明

　　　　http請(qǐng)求方式: GET

　　　　請(qǐng)求的URL地址：https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=APPID&secret=APPSECRET　　　　　　

我們可以看到,調(diào)用過程中需要傳遞appID和AppSecret,appID和AppSecret是在申請(qǐng)公眾號(hào)的時(shí)候自動(dòng)分配給公眾號(hào)的，相當(dāng)于公眾號(hào)的身份標(biāo)示，使用微信公眾號(hào)的注冊(cè)帳號(hào)登錄到騰訊提供的微信公眾號(hào)管理后臺(tái)就可以看到自己申請(qǐng)的公眾號(hào)的AppID和AppSecret，如下圖所示：

　　這是我申請(qǐng)公眾號(hào)測(cè)試帳號(hào)時(shí)分配到的AppID和AppSecret。

3.3、獲取access_token方案以及具體實(shí)現(xiàn)

　　這里采用的方案是這樣的，定義一個(gè)默認(rèn)啟動(dòng)的servlet，在init方法中啟動(dòng)一個(gè)Thread,這個(gè)進(jìn)程中定義一個(gè)無限循環(huán)的方法，用來獲取access_token，當(dāng)獲取成功后，此進(jìn)程休眠7000秒(7000秒=1.944444444444444小時(shí))，否則休眠3秒鐘繼續(xù)獲取。流程圖如下：

　　下面正式開始在工程中實(shí)現(xiàn)以上思路，因?yàn)榉祷氐臄?shù)據(jù)都是json格式，這里會(huì)用到阿里的fastjson庫(kù)，為構(gòu)造請(qǐng)求和處理請(qǐng)求后的數(shù)據(jù)序列化和反序列化提供支持。

　　1.定義一個(gè)AccessToken實(shí)體類

package me.gacl.wx.entry;

/**
 * AccessToken的數(shù)據(jù)模型
 * Created by xdp on 2016/1/25.
 */
public class AccessToken {

    //獲取到的憑證
    private String accessToken;
    //憑證有效時(shí)間，單位：秒
    private int expiresin;

    public String getAccessToken() {
        return accessToken;
    }

    public void setAccessToken(String accessToken) {
        this.accessToken = accessToken;
    }

    public int getExpiresin() {
        return expiresin;
    }

    public void setExpiresin(int expiresin) {
        this.expiresin = expiresin;
    }
}

　2.定義一個(gè)AccessTokenInfo類,用于存放獲取到的AccessToken,代碼如下:

package me.gacl.wx.Common;

import me.gacl.wx.entry.AccessToken;

/**
 * Created by xdp on 2016/1/25.
 */
public class AccessTokenInfo {

    //注意是靜態(tài)的
    public static AccessToken accessToken = null;
}

　　3.編寫一個(gè)用于發(fā)起https請(qǐng)求的工具類NetWorkHelper,代碼如下:

package me.gacl.wx.util;

import javax.net.ssl.*;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.URL;
import java.security.cert.CertificateException;
import java.security.cert.X509Certificate;

/**
 * 訪問網(wǎng)絡(luò)用到的工具類
 */
public class NetWorkHelper {

    /**
     * 發(fā)起Https請(qǐng)求
     * @param reqUrl 請(qǐng)求的URL地址
     * @param requestMethod
     * @return 響應(yīng)后的字符串
     */
    public String getHttpsResponse(String reqUrl, String requestMethod) {
        URL url;
        InputStream is;
        String resultData = "";
        try {
            url = new URL(reqUrl);
            HttpsURLConnection con = (HttpsURLConnection) url.openConnection();
            TrustManager[] tm = {xtm};

            SSLContext ctx = SSLContext.getInstance("TLS");
            ctx.init(null, tm, null);

            con.setSSLSocketFactory(ctx.getSocketFactory());
            con.setHostnameVerifier(new HostnameVerifier() {
                @Override
                public boolean verify(String arg0, SSLSession arg1) {
                    return true;
                }
            });


            con.setDoInput(true); //允許輸入流，即允許下載

            //在android中必須將此項(xiàng)設(shè)置為false
            con.setDoOutput(false); //允許輸出流，即允許上傳
            con.setUseCaches(false); //不使用緩沖
            if (null != requestMethod && !requestMethod.equals("")) {
                con.setRequestMethod(requestMethod); //使用指定的方式
            } else {
                con.setRequestMethod("GET"); //使用get請(qǐng)求
            }
            is = con.getInputStream();   //獲取輸入流，此時(shí)才真正建立鏈接
            InputStreamReader isr = new InputStreamReader(is);
            BufferedReader bufferReader = new BufferedReader(isr);
            String inputLine;
            while ((inputLine = bufferReader.readLine()) != null) {
                resultData += inputLine + "\n";
            }
            System.out.println(resultData);

        } catch (Exception e) {
            e.printStackTrace();
        }
        return resultData;
    }

    X509TrustManager xtm = new X509TrustManager() {
        @Override
        public X509Certificate[] getAcceptedIssuers() {
            return null;
        }

        @Override
        public void checkServerTrusted(X509Certificate[] arg0, String arg1)
                throws CertificateException {

        }

        @Override
        public void checkClientTrusted(X509Certificate[] arg0, String arg1)
                throws CertificateException {

        }
    };
}

　　getHttpsResponse方法是請(qǐng)求一個(gè)https地址，參數(shù)requestMethod為字符串“GET”或者“POST”，傳null或者“”默認(rèn)為get方式。

　　4.定義一個(gè)默認(rèn)啟動(dòng)的servlet，在init方法中啟動(dòng)一個(gè)新的線程去獲取accessToken

package me.gacl.wx.web.servlet;

import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONObject;
import me.gacl.wx.Common.AccessTokenInfo;
import me.gacl.wx.entry.AccessToken;
import me.gacl.wx.util.NetWorkHelper;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebInitParam;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;

/**
 * 用于獲取accessToken的Servlet
 * Created by xdp on 2016/1/25.
 */
@WebServlet(
        name = "AccessTokenServlet",
        urlPatterns = {"/AccessTokenServlet"},
        loadOnStartup = 1,
        initParams = {
                @WebInitParam(name = "appId", value = "wxbe4d433e857e8bb1"),
                @WebInitParam(name = "appSecret", value = "ccbc82d560876711027b3d43a6f2ebda")
        })
public class AccessTokenServlet extends HttpServlet {

    @Override
    public void init() throws ServletException {
        System.out.println("啟動(dòng)WebServlet");
        super.init();

        final String appId = getInitParameter("appId");
        final String appSecret = getInitParameter("appSecret");

        //開啟一個(gè)新的線程
        new Thread(new Runnable() {
            @Override
            public void run() {
                while (true) {
                    try {
                        //獲取accessToken
                        AccessTokenInfo.accessToken = getAccessToken(appId, appSecret);
                        //獲取成功
                        if (AccessTokenInfo.accessToken != null) {
                            //獲取到access_token 休眠7000秒,大約2個(gè)小時(shí)左右
                            Thread.sleep(7000 * 1000);
                            //Thread.sleep(10 * 1000);//10秒鐘獲取一次
                        } else {
                            //獲取失敗
                            Thread.sleep(1000 * 3); //獲取的access_token為空 休眠3秒
                        }
                    } catch (Exception e) {
                        System.out.println("發(fā)生異常：" + e.getMessage());
                        e.printStackTrace();
                        try {
                            Thread.sleep(1000 * 10); //發(fā)生異常休眠1秒
                        } catch (Exception e1) {

                        }
                    }
                }

            }
        }).start();
    }

    /**
     * 獲取access_token
     *
     * @return AccessToken
     */
    private AccessToken getAccessToken(String appId, String appSecret) {
        NetWorkHelper netHelper = new NetWorkHelper();
        /**
         * 接口地址為https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=APPID&secret=APPSECRET，其中g(shù)rant_type固定寫為client_credential即可。
         */
        String Url = String.format("https://api.weixin.qq.com/cgi-bin/token?grant_type=client_credential&appid=%s&secret=%s", appId, appSecret);
        //此請(qǐng)求為https的get請(qǐng)求，返回的數(shù)據(jù)格式為{"access_token":"ACCESS_TOKEN","expires_in":7200}
        String result = netHelper.getHttpsResponse(Url, "");
        System.out.println("獲取到的access_token="+result);
        //使用FastJson將Json字符串解析成Json對(duì)象
        JSONObject json = JSON.parseObject(result);
        AccessToken token = new AccessToken();
        token.setAccessToken(json.getString("access_token"));
        token.setExpiresin(json.getInteger("expires_in"));
        return token;
    }
}

　　AccessTokenServlet采用注解的方式進(jìn)行配置
　　至此代碼實(shí)現(xiàn)完畢，將項(xiàng)目部署，看到控制臺(tái)輸出如下：

　　為了方便看效果，可以把休眠時(shí)間設(shè)置短一點(diǎn)，比如10秒獲取一次，然后將access_token輸出。

　　下面做一個(gè)測(cè)試jsp頁(yè)面，并把休眠時(shí)間設(shè)置為10秒，這樣過10秒刷新頁(yè)面，就可以看到變化

<%-- Created by IntelliJ IDEA. --%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ page import="me.gacl.wx.Common.AccessTokenInfo"%>
<html>
  <head>
    <title></title>
  </head>
  <body>
    微信學(xué)習(xí)
    <hr/>
    access_token為：<%=AccessTokenInfo.accessToken.getAccessToken()%>
  </body>
</html>

　　10秒鐘后刷新頁(yè)面,access_token變了,如下圖所示:

四、接收微信服務(wù)器發(fā)送的消息并做出響應(yīng)

　　經(jīng)過上述的三步,我們開發(fā)前的準(zhǔn)備工作已經(jīng)完成了,接下來要做的就是接收微信服務(wù)器發(fā)送的消息并做出響應(yīng)

　　從微信公眾平臺(tái)接口消息指南中可以了解到，當(dāng)用戶向公眾帳號(hào)發(fā)消息時(shí)，微信服務(wù)器會(huì)將消息通過POST方式提交給我們?cè)诮涌谂渲眯畔⒅刑顚懙腢RL，而我們就需要在URL所指向的請(qǐng)求處理類WxServlet的doPost方法中接收消息、處理消息和響應(yīng)消息。

4.1.編寫一個(gè)用于處理消息的工具類

　　編寫處理消息的工具欄,工具類代碼如下:

package me.gacl.wx.util;

import org.dom4j.Document;
import org.dom4j.Element;
import org.dom4j.io.SAXReader;

import javax.servlet.http.HttpServletRequest;
import java.io.InputStream;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * 消息處理工具類
 * Created by xdp on 2016/1/26.
 */
public class MessageHandlerUtil {

    /**
     * 解析微信發(fā)來的請(qǐng)求（XML）
     * @param request
     * @return map
     * @throws Exception
     */
    public static Map<String,String> parseXml(HttpServletRequest request) throws Exception {
        // 將解析結(jié)果存儲(chǔ)在HashMap中
        Map<String,String> map = new HashMap();
        // 從request中取得輸入流
        InputStream inputStream = request.getInputStream();
        System.out.println("獲取輸入流");
        // 讀取輸入流
        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節(jié)點(diǎn)
        List<Element> elementList = root.elements();

        // 遍歷所有子節(jié)點(diǎn)
        for (Element e : elementList) {
            System.out.println(e.getName() + "|" + e.getText());
            map.put(e.getName(), e.getText());
        }

        // 釋放資源
        inputStream.close();
        inputStream = null;
        return map;
    }

    // 根據(jù)消息類型 構(gòu)造返回消息
    public static String buildXml(Map<String,String> map) {
        String result;
        String msgType = map.get("MsgType").toString();
        System.out.println("MsgType:" + msgType);
        if(msgType.toUpperCase().equals("TEXT")){
            result = buildTextMessage(map, "孤傲蒼狼在學(xué)習(xí)和總結(jié)微信開發(fā)了,構(gòu)建一條文本消息:Hello World!");
        }else{
            String fromUserName = map.get("FromUserName");
            // 開發(fā)者微信號(hào)
            String toUserName = map.get("ToUserName");
            result = String
                    .format(
                            "<xml>" +
                                    "<ToUserName><![CDATA[%s]]></ToUserName>" +
                                    "<FromUserName><![CDATA[%s]]></FromUserName>" +
                                    "<CreateTime>%s</CreateTime>" +
                                    "<MsgType><![CDATA[text]]></MsgType>" +
                                    "<Content><![CDATA[%s]]></Content>" +
                                    "</xml>",
                            fromUserName, toUserName, getUtcTime(),
                            "請(qǐng)回復(fù)如下關(guān)鍵詞：\n文本\n圖片\n語音\n視頻\n音樂\n圖文");
        }

        return result;
    }

    /**
     * 構(gòu)造文本消息
     *
     * @param map
     * @param content
     * @return
     */
    private static String buildTextMessage(Map<String,String> map, String content) {
        //發(fā)送方帳號(hào)
        String fromUserName = map.get("FromUserName");
        // 開發(fā)者微信號(hào)
        String toUserName = map.get("ToUserName");
        /**
         * 文本消息XML數(shù)據(jù)格式
         * <xml>
             <ToUserName><![CDATA[toUser]]></ToUserName>
             <FromUserName><![CDATA[fromUser]]></FromUserName>
             <CreateTime>1348831860</CreateTime>
             <MsgType><![CDATA[text]]></MsgType>
             <Content><![CDATA[this is a test]]></Content>
             <MsgId>1234567890123456</MsgId>
         </xml>
         */
        return String.format(
                "<xml>" +
                        "<ToUserName><![CDATA[%s]]></ToUserName>" +
                        "<FromUserName><![CDATA[%s]]></FromUserName>" +
                        "<CreateTime>%s</CreateTime>" +
                        "<MsgType><![CDATA[text]]></MsgType>" +
                        "<Content><![CDATA[%s]]></Content>" + "</xml>",
                fromUserName, toUserName, getUtcTime(), content);
    }

    private static String getUtcTime() {
        Date dt = new Date();// 如果不需要格式,可直接用dt,dt就是當(dāng)前系統(tǒng)時(shí)間
        DateFormat df = new SimpleDateFormat("yyyyMMddhhmm");// 設(shè)置顯示格式
        String nowTime = df.format(dt);
        long dd = (long) 0;
        try {
            dd = df.parse(nowTime).getTime();
        } catch (Exception e) {

        }
        return String.valueOf(dd);
    }
}

　　為了方便解析微信服務(wù)器發(fā)送給我們的xml格式的數(shù)據(jù),這里我們借助于開源框架dom4j去解析xml（這里使用的是dom4j-2.0.0-RC1.jar）

4.2.在WxServlet的doPost方法中處理請(qǐng)求

　　WxServlet的doPost方法的代碼如下:

/**
     * 處理微信服務(wù)器發(fā)來的消息
     */
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // TODO 接收、處理、響應(yīng)由微信服務(wù)器轉(zhuǎn)發(fā)的用戶發(fā)送給公眾帳號(hào)的消息
        // 將請(qǐng)求、響應(yīng)的編碼均設(shè)置為UTF-8（防止中文亂碼）
        request.setCharacterEncoding("UTF-8");
        response.setCharacterEncoding("UTF-8");
        System.out.println("請(qǐng)求進(jìn)入");
        String result = "";
        try {
            Map<String,String> map = MessageHandlerUtil.parseXml(request);
            System.out.println("開始構(gòu)造消息");
            result = MessageHandlerUtil.buildXml(map);
            System.out.println(result);
            if(result.equals("")){
                result = "未正確響應(yīng)";
            }
        } catch (Exception e) {
            e.printStackTrace();
            System.out.println("發(fā)生異常："+ e.getMessage());
        }
        response.getWriter().println(result);
    }

　　到此,我們的WxServlet已經(jīng)可以正常處理用戶的請(qǐng)求并做出響應(yīng)了.接下來我們測(cè)試一下我們開發(fā)好的公眾號(hào)應(yīng)用是否可以正常和微信用戶交互

　　將WxStudy部署到Tomcat服務(wù)器,啟動(dòng)服務(wù)器,記得使用ngrok將本地Tomcat服務(wù)器的8080端口映射到外網(wǎng),保證接口配置信息的URL地址:http://xdp.ngrok.natapp.cn/WxServlet可以正常與微信服務(wù)器通信

　　登錄到我們的測(cè)試公眾號(hào)的管理后臺(tái),然后用微信掃描一下測(cè)試號(hào)的二維碼,如下圖所示:

　　關(guān)注成功后,我們開發(fā)好的公眾號(hào)應(yīng)用會(huì)先給用戶發(fā)一條提示用戶操作的文本消息,微信用戶根據(jù)提示操作輸入"文本",我們的公眾號(hào)應(yīng)用接收到用戶請(qǐng)求后就給用戶回復(fù)了一條我們自己構(gòu)建好的文本消息,如下圖所示:

　　我們的公眾號(hào)應(yīng)用響應(yīng)給微信用戶的文本消息的XML數(shù)據(jù)如下:

<xml>
  <ToUserName><![CDATA[ojADgs0eDaqh7XkTM9GvDmdYPoDw]]></ToUserName>
  <FromUserName><![CDATA[gh_43df3882c452]]></FromUserName>
  <CreateTime>1453755900000</CreateTime>
  <MsgType><![CDATA[text]]></MsgType>
  <Content><![CDATA[孤傲蒼狼在學(xué)習(xí)和總結(jié)微信開發(fā)了,構(gòu)建一條文本消息:Hello World!]]></Content>
</xml>

　　測(cè)試公眾號(hào)的管理后臺(tái)也可以看到關(guān)注測(cè)試號(hào)的用戶列表,如下圖所示:

　　通過這個(gè)簡(jiǎn)單的入門程序,我們揭開了微信開發(fā)的神秘面紗了.

　更多Summary of introductory learning for WeChat development相關(guān)文章請(qǐng)關(guān)注PHP中文網(wǎng)！