微信公众号的开发教程Java版本

1、首先，去官网注册一个微信公众号

2、点击开发者中心，填写服务器配置信息

3、通过ngrok来映射本地的请求到服务器端

4、通过代码来验证请求，并给出相应的回复，不多说，贴代码

package com.weixin.action;

import java.io.IOException;
/*
 * 第一次请求的时候是get请求，用户验证
 * 第二次请求就是Post请求，传递消息和返回消息
 */
import java.io.PrintWriter;
import java.util.Map;

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

public class WeixinServlet extends HttpServlet{

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        /*
         * 获取参数，然后验证是否是正确的连接应用
         */
        String signature = req.getParameter("signature");
        String timestamp = req.getParameter("timestamp");
        String nonce = req.getParameter("nonce");
        String echostr = req.getParameter("echostr");
        PrintWriter out = resp.getWriter();
        if(CheckUtil.checkSignature(signature, timestamp, nonce)){
            out.print(echostr);
        }
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp)
            throws ServletException, IOException {
        // TODO Auto-generated method stub
        req.setCharacterEncoding("UTF-8");
        resp.setCharacterEncoding("UTF-8");
        Map<String,String> map = MessageUtil.readStringXmlOut(req, null);
        String ToUserName = map.get("ToUserName");
        String FromUserName = map.get("FromUserName");
    //    String CreateTime = map.get("CreateTime");
        String Content = map.get("Content");
    //    String MsgId = map.get("MsgId");
        String MsgType = map.get("MsgType");
        PrintWriter writer = resp.getWriter();
        String msg = null;
        if(MessageUtil.MESSAGE_TEXT.equals(MsgType)){
            if("1".equals(Content)){
                Content = "你好";
            }else if("2".equals(Content)){
                Content = "暂时";
            }
            msg = MessageUtil.initText(ToUserName, FromUserName, Content);
        }else if(MessageUtil.MESSAGE_EVENT.equals(MsgType)){
            String event = map.get("event");
            if(MessageUtil.MESSAGE_SUBSCRIBE.equals(event)){
                msg = MessageUtil.initText(ToUserName, FromUserName, MessageUtil.menuText());
            }
        }
        writer.print(msg);
        writer.close();
        
    }
    
    

}

5、验证请求是否合法sha1验证

package com.weixin.action;

import java.util.Arrays;

public class CheckUtil {
    
    private static final String token = "imooc";
    
    public static boolean checkSignature(String signature,String timestamp,String nonce){
        String[] arr = new String[]{token,timestamp,nonce};
        Arrays.sort(arr);
        //生成字符串
        StringBuffer content = new StringBuffer();
        for(int i = 0; i< arr.length;i++){
            content.append(arr[i]);
        }
        //sha1加密
        //String temp = new SHA1().getDigestOfString(content.toString().getBytes()).toLowerCase();
        String temp = Util.sha1(content.toString()).toLowerCase();
        return temp.equals(signature);
    }
}

package com.weixin.action;

import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;

public class Util {

    /**
     * sha1加密
     * 
     * @author qincd
     * @date Nov 3, 2014 4:16:39 PM
     */
    public static String sha1(String str) {
        if (str == null || str.length() == 0)
            return "";
        try {
            MessageDigest md = MessageDigest.getInstance("SHA1");
            byte[] bytes = md.digest(str.getBytes());
            return byte2Hex(bytes);
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
            throw new RuntimeException("SHA1加密出错");
        }
    }

    public static String byte2Hex(byte[] data) {
        if (data == null || data.length == 0)
            return "";
        StringBuilder sbu = new StringBuilder();
        for (int i = 0; i < data.length; i++) {
            if ((data[i] & 0xff) < 0x10) {
                sbu.append("0");
            }
            sbu.append(Integer.toHexString(data[i] & 0xff));
        }
        return sbu.toString();
    }
}

6、处理请求

package com.weixin.action;

public class MessageText {
    
    private String Content;
    private String CreateTime;
    private String FromUserName;
    private String MsgID;
    private String MsgType;
    private String ToUserName;
    
    public MessageText() {
        // TODO Auto-generated constructor stub
    }

    public MessageText(String toUserName, String fromUserName,
            String createTime, String msgType, String content, String msgID) {
        ToUserName = toUserName;
        FromUserName = fromUserName;
        CreateTime = createTime;
        MsgType = msgType;
        Content = content;
        MsgID = msgID;
    }

    public String getContent() {
        return Content;
    }

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

    public String getCreateTime() {
        return CreateTime;
    }

    public void setCreateTime(String createTime) {
        CreateTime = createTime;
    }

    public String getFromUserName() {
        return FromUserName;
    }

    public void setFromUserName(String fromUserName) {
        FromUserName = fromUserName;
    }

    public String getMsgID() {
        return MsgID;
    }

    public void setMsgID(String msgID) {
        MsgID = msgID;
    }

    public String getMsgType() {
        return MsgType;
    }

    public void setMsgType(String msgType) {
        MsgType = msgType;
    }

    public String getToUserName() {
        return ToUserName;
    }

    public void setToUserName(String toUserName) {
        ToUserName = toUserName;
    }

}

7、协助处理请求的工具类

package com.weixin.action;

import java.io.IOException;
import java.io.InputStream;
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;

public class MessageUtil {
    
    public static final String  MESSAGE_TEXT = "text";
    public static final String  MESSAGE_IMAGE = "image";
    public static final String  MESSAGE_VOICE = "voice";
    public static final String  MESSAGE_VIDEO = "video";
    public static final String  MESSAGE_SHORTVIDEO = "shortvideo";    
    public static final String  MESSAGE_LOCATION = "location";
    public static final String  MESSAGE_LINK = "link";
    public static final String  MESSAGE_EVENT = "event";
    public static final String  MESSAGE_SUBSCRIBE = "subscribe";
    public static final String  MESSAGE_UNSUBSCRIBE = "unsubscribe";
    public static final String  MESSAGE_SCAN = "SCAN";
    public static final String  MESSAGE_LOCATIONs = "LOCATION";
    public static final String  MESSAGE_CLICK = "CLICK";
    public static final String  MESSAGE_VIEW = "VIEW";
    
    
    public static Map readStringXmlOut(HttpServletRequest req,String xml) {
         Map map = new HashMap();
         Document doc = null;
         InputStream stream = null;
         // 将字符串转为XML
        try {
            SAXReader reader = new SAXReader();
            stream = req.getInputStream();
            doc = reader.read(stream);
            Element rootElt = doc.getRootElement();
            List<Element> es = rootElt.elements();
            for(Element e:es){
                map.put(e.getName(), e.getText());
            }
        } catch (DocumentException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }finally{
            try {
                if(stream!=null){
                    stream.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        // 获取根节点
         return map;
    }
    
    public static String objToXml(MessageText text){
        XStream xml = new XStream();
        xml.alias("xml", text.getClass());
        return xml.toXML(text);
    }
    
    /*
     * 主菜单
     */
    public static String menuText(){
        StringBuffer sb = new StringBuffer();
        sb.append("欢迎您的关注，请按照才对提示进行操作\n\n");
        sb.append("1、小村长介绍。");
        sb.append("2、小村庄介绍");
        sb.append("回复？调出主菜单");
        return sb.toString();
    }
    
    /*
     * 拼接文本消息
     */
    public static String initText(String ToUserName,String FromUserName,String Content){
        MessageText text = new MessageText();
        text.setFromUserName(ToUserName);
        text.setToUserName(FromUserName);
        text.setMsgType("text");
        text.setCreateTime(System.currentTimeMillis()+"");
        text.setContent(Content);
        return MessageUtil.objToXml(text);
    }
}