java get micro-binding letter openid user, free landing.

• Concise, clear, no bullshit, things did not get off before the micro-letter, get a bad morning with the code be run through.
• Testing framework I use springMVC.
• The need to penetrate the network, please download natapp official website address  https://natapp.cn/ , Tutorial: NATAPP1 minute quick novice graphic tutorials
• Need a micro-channel public number, use this demo is to test the number of public access Address:  https://mp.weixin.qq.com/debug/cgi-bin/sandbox?t=sandbox/login
• Need to focus on your own test public number.
• Please ask about micro-channel authorization  https://developers.weixin.qq.com/doc/offiaccount/OA_Web_Apps/Wechat_webpage_authorization.html
• No public test configuration

1. 
2. JS interface security domain to fill out your own domain name after the local penetration without http: //

3. Experience Interface permissions table -> Web Services -> Web account or fill out the last step of the domain name without http: //

• The following code starts ↓↓ ↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓ ↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓

•  @RequestMapping(params = "toUrl",method=RequestMethod.GET)
  	    public void toUrl(HttpServletRequest request,HttpServletResponse response){
  	    	StringBuffer sb = new StringBuffer();
  	        //公众号appId
  	        String appId = "appidxxxxxxxxxxxxxxx";
  	        //目标方法或者页面 先获取code 换取openId 一个微信用户对应关注的微信号只有一个唯一的openId  在其他关注的公账号下openId不同 
  	        String doname = "带http://的域名/xxxxxController.do?getCode";
  	        sb.append("https://open.weixin.qq.com/connect/oauth2/authorize?appid=");
  	        sb.append(appId);
  	        String url = "";
  	        try {
  //	            url = URLEncoder.encode(encodeUrl.toString(), "utf-8");
  	            url = URLEncoder.encode(doname, "utf-8");
  	            sb.append("&redirect_uri=").append(url);
  	            //网页授权的静默授权snsapi_base
  	            sb.append("&response_type=code&scope=snsapi_userinfo&state=123#wechat_redirect");
  	            response.sendRedirect(sb.toString());
  	        } catch (UnsupportedEncodingException e) {
  	            System.out.println("重定向url编码失败：>>" + e.getMessage());   
  	            e.printStackTrace();
  	        } catch (Exception e) {
  	        	 System.out.println("response重定向失败：>>" + e.getMessage());   
  	            e.printStackTrace();
  	        }
  	    }
  	    

    @RequestMapping(params = "getCode",method=RequestMethod.GET)
  	    public void toMyPage(HttpServletRequest request,HttpServletResponse response){
  	        //获取重定向携带的code参数值
  	        String code = request.getParameter("code");
  	        String openId = "";
  	        if (StringUtils.isEmpty(openId)) {
  	            /*
  	            * 根据得到的code参数，内部请求获取openId的方法。
  	             */
  	            openId = getOpenId(request,response,code);
  	        }
  	    }
  
  
  
   //发送请求，根据code获取openId
  	    public String getOpenId(HttpServletRequest request, HttpServletResponse response,String code) {
  	        String content = "";
  	        String openId = "";
  	        String unionId = "";
  	        String appId = "appidxxxxxxxxxxxxxxx";//公众号的appId
  	        String appsecret="appsecretxxxxxxxxxxxxx"; //公众号的appsecret
  	        //封装获取openId的微信API
  	        StringBuffer url = new StringBuffer();
  	        url.append("https://api.weixin.qq.com/sns/oauth2/access_token?appid=")
  	        .append(appId)
  	        .append("&secret=")
  	        .append(appsecret)
  	        .append("&code=")
  	        .append(code)
  	        .append("&grant_type=authorization_code");
  	        
  	        ObjectMapper objectMapper = new ObjectMapper();
  	        try {
  	        	CloseableHttpClient httpClient = HttpClientBuilder.create().build();
  	        	HttpGet httpGet = new HttpGet(url.toString());
  	        	CloseableHttpResponse re = null;
  	        	re = httpClient.execute(httpGet);
  	        	HttpEntity responseEntity = re.getEntity();
  	        	
  	            content = EntityUtils.toString(responseEntity);
  	            Map map = objectMapper.readValue(content, Map.class);
  	            openId = String.valueOf(map.get("openid"));
  	            unionId = String.valueOf(map.get("unionid"));
  	            System.out.println("获取的openID：" + openId);
  	            /*
  		             * 将openId保存到session中，当其他业务获取openId时，
  		             * 可先从session中获取openId.
  	             */
  	            request.getSession().setAttribute("openId", openId);
                   /*
  		             
  		             * 获取到openid就可写绑定用户方法了
  	             */
                 
  	        } catch (JsonParseException e) {
  	        	 System.out.println("json解析失败：");
  	        } catch (JsonMappingException e) {
  	        	 System.out.println("map转换成json失败：");
  	        } catch (Exception e) {
  	        	 System.out.println("http获取openId请求失败：");
  	        }
  	        return openId;
  	    }

  Caishuxueqian brother, want to write to say clearly understand.