JAVA微信开发-新手接入指南

相信很多人对微信开发已经不那么陌生，我也是从一个微信开发的菜鸟经过各种问题的折磨，然后去搜索引擎搜索各种文章阅读，但是基本都是零散的资料，没有一个统一、系统的阐述微信应用如何开发。作者结合自己的实际开发经验，归纳整理出来分享给微信开发的入门者或正在研究的开发者。

这篇文章主要阐述如何搭建一个微信开发平台。古人云：“磨刀不负砍才工”。我们开发应用也需要准备一些必要的条件。

 准备工作

1.  下载 Jdk1.7  安装

2.  下载 Tomcat 7.0

3.  下载 Myeclipse 6.5

4.  下载 Json-lib第三方jar .

1.      申请一个公网IP地址，发布自己的应用。

例如： 192.168.1.102

2.      打开myeclipse 创建一个工程

如下图所示：

3.  创建一个微信应用接入Servlet类

JAVA实现类 ：WeixinServlet

package com.wx.servlet;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.util.Arrays;
import java.util.logging.Logger;

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

import net.sf.json.JSONObject;
import net.sf.json.xml.XMLSerializer;

/**
 * @author haibing.xiao
 * @since jdk1.6
 * @version 1.0
 */
public class WeixinServlet extends HttpServlet{

    private Logger log =Logger.getLogger(this.getClass().getName());
    private static final long serialVersionUID = 1L;
    private   String Token;
    private   String echostr;
    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
         connect(request,response);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response)
            throws ServletException, IOException {
        message(request,response);
    }

    /**
     *@author haibing.xiao
     *@return
     *@exception
     *@param
     *
     * <p>接入连接生效验证</p>
     */
    private void connect(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException{
        log.info("RemoteAddr: "+ request.getRemoteAddr());
        log.info("QueryString: "+ request.getQueryString());
         if(!accessing(request, response)){
             log.info("服务器接入失败.......");
             return ;
         }
        String echostr=getEchostr();
        if(echostr!=null && !"".equals(echostr)){
                log.info("服务器接入生效..........");
                response.getWriter().print(echostr);//完成相互认证
        }
    }
    /**
     * @author haibing.xiao
     * Date 2013-05-29
     * @return boolean
     * @exception ServletException, IOException
     * @param
     *
     *<p>用来接收微信公众平台的验证</p>
     */
    private boolean accessing(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {
        String signature = request.getParameter("signature");
        String timestamp = request.getParameter("timestamp");
        String nonce = request.getParameter("nonce");
        String echostr = request.getParameter("echostr");
        if( isEmpty(signature)){
            return false;
        }
        if(isEmpty(timestamp)){
            return false;
        }
        if(isEmpty(nonce)){
            return false;
        }
        if(isEmpty(echostr)){
            return false;
        }
        String[] ArrTmp = { Token, timestamp, nonce };
        Arrays.sort(ArrTmp);
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < ArrTmp.length; i++) {
            sb.append(ArrTmp[i]);
        }
        String pwd = Encrypt(sb.toString());

        log.info("signature:"+signature+"timestamp:"+timestamp+"nonce:"+nonce+"pwd:"+pwd+"echostr:"+echostr);

        if(trim(pwd).equals(trim(signature))){
            this.echostr =echostr;
            return true;
        }else{
            return false;
        }
    }
    private String Encrypt(String strSrc) {
        MessageDigest md = null;
        String strDes = null;

        byte[] bt = strSrc.getBytes();
        try {
            md = MessageDigest.getInstance("SHA-1");
            md.update(bt);
            strDes = bytes2Hex(md.digest()); //to HexString
        } catch (NoSuchAlgorithmException e) {
            System.out.println("Invalid algorithm.");
            return null;
        }
        return strDes;
    }

    public String bytes2Hex(byte[] bts) {
        String des = "";
        String tmp = null;
        for (int i = 0; i < bts.length; i++) {
            tmp = (Integer.toHexString(bts[i] & 0xFF));
            if (tmp.length() == 1) {
                des += "0";
            }
            des += tmp;
        }
        return des;
    }

    public String getEchostr(){
        return echostr;
    }
    /**
     *@author haibing.xiao
     *@return
     *@exception ServletException, IOException
     *@param
     *
     * <p>XML组装组件</p>
     */
     private void message(HttpServletRequest request,HttpServletResponse response) throws ServletException, IOException{

            InputStream is = request.getInputStream();
            // 取HTTP请求流长度
            int size = request.getContentLength();
            // 用于缓存每次读取的数据
            byte[] buffer = new byte[size];
            // 用于存放结果的数组
            byte[] xmldataByte = new byte[size];
            int count = 0;
            int rbyte = 0;
            // 循环读取
            while (count < size) {
                // 每次实际读取长度存于rbyte中
                rbyte = is.read(buffer);
                for(int i=0;i<rbyte;i++) {
                    xmldataByte[count + i] = buffer[i];
                }
                count += rbyte;
            }
            is.close();
            String requestStr = new String(xmldataByte, "UTF-8");

            try{
                manageMessage(requestStr,request,response);
            }catch(Exception e){
                e.printStackTrace();
            }

        }

    /**
     * @author haibing.xiao
     * @return
     * @exception ServletException, IOException
     * @param
     *
     * <p>业务转发组件</p>
     *
     */
      private void  manageMessage(String requestStr,HttpServletRequest request,HttpServletResponse response)throws ServletException,IOException{

            String responseStr;

            try {
                 XMLSerializer xmlSerializer=new XMLSerializer();
                 JSONObject jsonObject =(JSONObject) xmlSerializer.read(requestStr);
                 String event =jsonObject.getString("Event");
                 String msgtype =jsonObject.getString("MsgType");
                 if("CLICK".equals(event) && "event".equals(msgtype)){ //菜单click事件
                     String eventkey =jsonObject.getString("EventKey");
                     if("hytd_001".equals(eventkey)){ // hytd_001 这是好友团队按钮的标志值
                         jsonObject.put("Content", "欢迎使用好友团队菜单click按钮.");
                     }

                 }
                 responseStr =creatRevertText(jsonObject);//创建XML
                 log.info("responseStr:"+responseStr);
                 OutputStream os =response.getOutputStream();
                 os.write(responseStr.getBytes("UTF-8"));
            }   catch (Exception e) {
                e.printStackTrace();
            }

    }
    private String creatRevertText(JSONObject jsonObject){
            StringBuffer revert =new StringBuffer();
            revert.append("<xml>");
            revert.append("<ToUserName><![CDATA["+jsonObject.get("ToUserName")+"]]></ToUserName>");
            revert.append("<FromUserName><![CDATA["+jsonObject.get("FromUserName")+"]]></FromUserName>");
            revert.append("<CreateTime>"+jsonObject.get("CreateTime")+"</CreateTime>");
            revert.append("<MsgType><![CDATA[text]]></MsgType>");
            revert.append("<Content><![CDATA["+jsonObject.get("Content")+"]]></Content>");
            revert.append("<FuncFlag>0</FuncFlag>");
            revert.append("</xml>");
            return revert.toString();
        }
    @Override
    public void init() throws ServletException {
        Token="test123";
    }

    private boolean isEmpty(String str){
        return null ==str || "".equals(str) ? true :false;
    }
    private String trim(String str){
        return null !=str  ? str.trim() : str;
    }

}

4.   本地部署应用  访问http://localhost:端口号/上下文/wenxin

5  .申请成为开发者

访问 http://mp.weixin.qq.com   ，开启开发者模式。填入URL和taken，申请成功，如下所示：

填入URL：http://外网IP/TestWeixin/weixin 【必须80端】

填入token :  test123【需要与代码中的token保持一致，Token的长度是有限制的，根据笔者的经验最好不超过10个字符。】