其实在weixin4j中，已经为大家提供了一个默认的消息接入Filter，大家只需要将jar包引入，然后配置一下web.xml和weixin4j.properties，然后部署web项目，也可以实现新手接入。
首先先展示一下默认的Filter源码
[java] view plain copy print ? /* * 微信公众平台(JAVA) SDK * * Copyright (c) 2014, Ansitech Network Technology Co.,Ltd All rights reserved. * * http://www.weixin4j.org/sdk/ * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package org.weixin4j; import org.weixin4j.message.Articles; import org.weixin4j.message.OutputMessage; import org.weixin4j.message.TextOutputMessage; import org.weixin4j.message.Video; import org.weixin4j.message.VideoOutputMessage; import org.weixin4j.spi.IMessageHandler; import org.weixin4j.spi.InputMessage; import org.weixin4j.util.TokenUtil; import org.weixin4j.util.XStreamFactory; import com.thoughtworks.xstream.XStream; import java.io.IOException; import java.lang.reflect.Field; import java.lang.reflect.Method; import java.util.Date; import javax.servlet.Filter; import javax.servlet.FilterChain; import javax.servlet.FilterConfig; import javax.servlet.ServletException; import javax.servlet.ServletInputStream; import javax.servlet.ServletRequest; import javax.servlet.ServletResponse; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * <p>Title: 微信公众平台接受消息拦截器</p> * * <p>Description: 拦截Url http://www.weixin4j.org/api/vzhanqun</p> * * @author weixin4j<weixin4j@ansitech.com> */ public class WeixinUrlFilter implements Filter { private String _token; private static IMessageHandler messageHandler = null; private static String defaultHandler = "org.weixin4j.spi.DefaultMessageHandler"; @Override public void init(FilterConfig config) throws ServletException { if (Configuration.isDebug()) { System.out.println("WeixinUrlFilter启动成功!"); } } @Override public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException { HttpServletRequest request = (HttpServletRequest) req; HttpServletResponse response = (HttpServletResponse) res; //微信服务器将发送GET请求到填写的URL上,这里需要判定是否为GET请求 boolean isGet = request.getMethod().toLowerCase().equals("get"); if (Configuration.isDebug()) { System.out.println("获得微信请求:" + request.getMethod() + " 方式"); System.out.println("微信请求URL:" + request.getServletPath()); } if (isGet) { String path = request.getServletPath(); //1.验证消息真实性 //http://mp.weixin.qq.com/wiki/index.php?title=验证消息真实性 //URL为http://www.weixin4j.org/api/公众号 //Token为weixin4j.properties中配置的Token //获取微信公众号 String gongzonghao = path.substring(path.lastIndexOf("/")); //如果获取不到公众号，则向服务器发生错误信息 if (gongzonghao == null) { response.getWriter().write("error"); } else { //根据公众号，算出对应的Token,然后进行验证 gongzonghao = gongzonghao.substring(1); //算出公众号的Token _token = TokenUtil.get(gongzonghao); if (Configuration.isDebug()) { System.out.println("取出公众号加密后的Token:" + _token); } //token为空，则请求地址错误 if (!_token.equals("")) { //成为开发者验证 doGet(request, response); } } } else { //用户每次向公众号发送消息、或者产生自定义菜单点击事件时，响应URL将得到推送 doPost(request, response); } } //开发者提交信息后，微信服务器将发送GET请求到填写的URL上 private void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException { String signature = request.getParameter("signature");// 微信加密签名 String timestamp = request.getParameter("timestamp");// 时间戳 String nonce = request.getParameter("nonce");// 随机数 String echostr = request.getParameter("echostr");// //确认此次GET请求来自微信服务器，原样返回echostr参数内容，则接入生效，成为开发者成功，否则接入失败 if (TokenUtil.checkSignature(_token, signature, timestamp, nonce)) { response.getWriter().write(echostr); } } //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 //用户在关注与取消关注公众号时，微信会把这个事件推送到开发者填写的URL //用户每次发送语音给公众号时，微信会在推送的语音消息XML数据包中，增加一个Recongnition字段 private void doPost(HttpServletRequest request, HttpServletResponse response) throws IOException { InputMessage inputMsg = null; OutputMessage outputMsg = null; try { response.setCharacterEncoding("UTF-8"); response.setContentType("text/xml"); if (messageHandler == null) { try { //获取 defaultHandler = Configuration.getProperty("weixin4j.handler", defaultHandler); if (Configuration.isDebug()) { System.out.println("微信接受消息处理Hanle:" + defaultHandler); } // 加载处理器 Class<?> clazz = Class.forName(defaultHandler); try { messageHandler = (IMessageHandler) clazz.newInstance(); } catch (Exception ex) { System.out.println("初始化 MessageHandler 异常："); ex.printStackTrace(); } } catch (ClassNotFoundException ex) { System.out.println("找不到: " + defaultHandler + " 类!"); ex.printStackTrace(); throw ex; } } if (Configuration.isDebug()) { System.out.println("IMessageHandler创建成功!"); } //获取POST流 ServletInputStream in = request.getInputStream(); if (Configuration.isDebug()) { System.out.println("获取POST流成功!"); } //将POST流转换为XStream对象 XStream xs = XStreamFactory.init(false); if (Configuration.isDebug()) { System.out.println("将POST流转换为XStream对象成功!"); } //将指定节点下的xml节点数据转换为对象 xs.alias("xml", InputMessage.class); if (Configuration.isDebug()) { System.out.println("将指定节点下的xml节点数据转换为对象成功!"); } //将流转换为字符串 String xmlMsg = XStreamFactory.inputStream2String(in); if (Configuration.isDebug()) { System.out.println("获取POST的消息:[" + xmlMsg + "]"); } //将xml内容转换为InputMessage对象 inputMsg = (InputMessage) xs.fromXML(xmlMsg); // 取得消息类型 String MsgType = inputMsg.getMsgType(); if (Configuration.isDebug()) { System.out.println("POST的消息类型:[" + MsgType + "]"); } //获取消息处理方法 Method mt = messageHandler.getClass().getMethod(MsgType + "TypeMsg", InputMessage.class); //调用处理方法，返回输出流对象 outputMsg = (OutputMessage) mt.invoke(messageHandler, inputMsg); //如果输出流为null，则说明内部异常 if (outputMsg == null) { //告知用户错误信息 outputMsg = new TextOutputMessage(); ((TextOutputMessage) outputMsg).setContent("系统错误，请联系管理员!"); } } catch (Exception ex) { ex.printStackTrace(); outputMsg = new TextOutputMessage(); ((TextOutputMessage) outputMsg).setContent("系统错误!"); } try { setOutputMsgInfo(outputMsg, inputMsg); } catch (Exception e1) { e1.printStackTrace(); } // 把发送发送对象转换为xml输出 XStream xs = XStreamFactory.init(true); xs.alias("xml", outputMsg.getClass()); xs.alias("item", Articles.class); String xml = xs.toXML(outputMsg); if (Configuration.isDebug()) { System.out.println("POST输出消息:[" + xml + "]"); } response.getWriter().write(xml); } //设置详细信息 private static void setOutputMsgInfo(OutputMessage oms, InputMessage msg) throws Exception { // 设置发送信息 Class<?> outMsg = oms.getClass().getSuperclass(); Field CreateTime = outMsg.getDeclaredField("CreateTime"); Field ToUserName = outMsg.getDeclaredField("ToUserName"); Field FromUserName = outMsg.getDeclaredField("FromUserName"); ToUserName.setAccessible(true); CreateTime.setAccessible(true); FromUserName.setAccessible(true); CreateTime.set(oms, new Date().getTime()); ToUserName.set(oms, msg.getFromUserName()); FromUserName.set(oms, msg.getToUserName()); } @Override public void destroy() { } }
源码大家可以看，也可以不看。
下面教大家，直接在web.xml中，加一个Filter即可。
[html] view plain copy print ? <!-- 默认Filter方式 微信接入配置 --> <servlet> <servlet-name>wechatFilter</servlet-name> <servlet-class>org.weixin4j.WeixinUrlFilter</servlet-class> </servlet> <servlet-mapping> <servlet-name>wechatFilter</servlet-name> <url-pattern>/api/*</url-pattern> </servlet-mapping>最后，将项目打包，发布到服务器，就可以在微信公众号平台中，进行开发者接入认证了。
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