最近在弄微信支付，网站有好几种不同类型的"商品"，去每个支付的页面都需要获取用户的OpenId，而且获取openid要在微信的浏览器去发送请求，如果有三个不同类型的付款页面就需要写三个一样获取openid的方法，这为了以后如果网站需要在其他的地方获取openid，为了扩展所以lz想了一个办法 把获取微信openId的方法抽取成了用注解和spring mvc的拦截器来实现。废话不多说下面直接上代码。

1.获取微信openid 网页授权代码

这里就不详细说啦，可以参照微信开发文档，下面也会体现到网页授权

注解代码实现

package com.workit.handler;import java.lang.annotation.Documented;import java.lang.annotation.ElementType;import java.lang.annotation.Retention;import java.lang.annotation.RetentionPolicy;import java.lang.annotation.Target;/** * * @Title: WeiXinGetOpenId.java* @Description: 获取openId注解，needGetOpenId 为true时调用获取openid* @date 2017年5月9日 下午4:12:02* @version V1.0 */@Target({ElementType.TYPE, ElementType.METHOD})@Retention(RetentionPolicy.RUNTIME)@Documentedpublic @interface WeiXinGetOpenId {      /**    *     * @Title: needGetOpenId    * @Description: 是否需要获取OpenId。    * @param @return        * @return boolean    */    boolean needGetOpenId() default false;    /**     *      * @Title: needGetUserInfo     * @Description: 是否需要获取用户信息。     * @param @return         * @return boolean     */    boolean needGetUserInfo() default false;        /**     *      * @Title: scopeType     * @Description: 授权方式     * @param @return         * @return String     */    String scopeType() default  "snsapi_base";    }

spring mvc配置文件加入下代码

拦截器代码实现类

package com.workit.handler;import java.net.URLEncoder;import java.util.Enumeration;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.springframework.web.method.HandlerMethod;import org.springframework.web.servlet.HandlerInterceptor;import org.springframework.web.servlet.ModelAndView;import com.alibaba.fastjson.JSONObject;import com.workit.comm.util.GlobalConstant;import com.workit.comm.util.String.StringUtil;import com.workit.comm.util.weixin.WeiXinConstant;import com.workit.comm.util.weixin.WeiXinUtil;/**   * @Title: WeixinGetOpenIdHandlerInterceptor.java* @Description: TODO* @date 2017年5月9日 上午10:56:45* @version V1.0   */public class WeixinGetOpenIdHandlerInterceptor implements HandlerInterceptor {	@Override	public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler)			throws Exception {		 if (handler instanceof HandlerMethod) {	            HandlerMethod method = (HandlerMethod) handler;	            WeiXinGetOpenId annotation = method.getMethodAnnotation(WeiXinGetOpenId.class);	            if(WeiXinUtil.checkWeiXinAgent(request)){		            if (annotation != null) {		                boolean needGetOpenId = annotation.needGetOpenId();		                String scopeType= annotation.scopeType();		                if (needGetOpenId) {		                	String url =request.getRequestURI();		                	String methodType = request.getMethod();		     	            @SuppressWarnings("rawtypes")							Enumeration enu=request.getParameterNames();  		     	            JSONObject json = new JSONObject();		     	            json.put("targetUrl",url);		     	            json.put("submitMethodType",methodType);		     	            while(enu.hasMoreElements()){  		     		            String paraName=(String)enu.nextElement();  		     		            json.put(paraName, request.getParameter(paraName));		     	            }		     	            //说明已经获取过OpenId		     	           if(StringUtil.isNotEmpty(json.get("weiXinGetOpenIdFlag"))){		     	            	return true;		     	            }else{				     	        String jsonParams = json.toJSONString();				     	      	String returnUrl ="网站名字"+"/WeiXinCommGetOpenId.html?weixin_outh2_params="+jsonParams;				     	      	returnUrl=URLEncoder.encode(returnUrl,"UTF-8");				     	      	String scope =scopeType;				     	      	returnUrl = WeiXinConstant.WEIXIN_AUTH_URL.replace("APPID",GlobalConstant.SERVICE_APPID).replace("REDIRECT_URI", returnUrl).replace("SCOPE", scope);				     	      	response.sendRedirect(returnUrl);				     	      	return false;		     	            }		                }		            }	            }	        }	        return true;	}	@Override	public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler,			ModelAndView modelAndView) throws Exception {		// TODO Auto-generated method stub			}	@Override	public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex)			throws Exception {		// TODO Auto-generated method stub			}}

获取OpenId的类

package com.workit.handler;import java.io.IOException;import java.io.PrintWriter;import java.util.HashMap;import java.util.Iterator;import java.util.Map;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import org.json.JSONObject;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import com.workit.comm.util.weixin.WeiXinUtil;/**   * @Title: WeiXinCommGetOpenId.java* @Description: TODO* @date 2017年5月9日 下午1:45:30* @version V1.0   */@Controllerpublic class WeiXinCommGetOpenId {	private static final Logger logger = LoggerFactory.getLogger(WeiXinCommGetOpenId.class);		@RequestMapping("/WeiXinCommGetOpenId.html")	public void getWeiXinCommOpenId(HttpServletRequest request,HttpServletResponse response) throws IOException{		Map
    
      paramMap = new HashMap
     
      ();		String postUrl ="";		try {			String code = request.getParameter("code");			String weixin_outh2_params = request.getParameter("weixin_outh2_params");			JSONObject json = new JSONObject(weixin_outh2_params);	 		String clickOpenId = WeiXinUtil.getUserInfoOpenId(code);	 		Iterator
       it = json.keys();	 		postUrl = json.getString("targetUrl");	 		if(postUrl.contains("网站名字")){	 			postUrl = postUrl.replace("网站名字/","");	 		}	 		postUrl ="网站名字"+postUrl;	 		paramMap.put("weiXinOpenId", clickOpenId);	 		paramMap.put("weiXinGetOpenIdFlag","isTure");			 while (it.hasNext()) {  			     String key = (String) it.next();  			     String value = json.getString(key); 			     paramMap.put(key, value);			 }  		} finally {			// TODO: handle finally clause			doReq(response, postUrl, paramMap);		}					}	 /**     *      * @param response     * @param postUrl     * @param paramMap     * @throws IOException     */	public static void doReq(HttpServletResponse response,String postUrl,Map
      
        paramMap) throws IOException {		 logger.debug("go into doReq method");		response.setContentType("text/html;charset=utf-8");   	    PrintWriter out = response.getWriter();  	    String type =(String) paramMap.get("submitMethodType");	    out.println("
       
        ");  	    for (String key : paramMap.keySet()) {	    	out.println("
        ");		}	    out.println("
       
");   	    out.println("
       ");  	    logger.debug("======doReq =====");	}}
      
     
    

使用只要在获取需要获取OPenID的方法前面加上注解

@WeiXinGetOpenId(needGetOpenId=true)

在方法里通过request.getParams("weiXinOpenId")