相信官方文檔，以前的接口錯誤已經改正，用最新的即可，這幾篇隨筆是一個項目中拿出來的，缺什麽方法去其他隨筆裏找找就有

 1 import java.io.IOException;
 2 import java.io.UnsupportedEncodingException;
 3 import javax.servlet.ServletException;
 4 import java.net.URLEncoder;
 5 import java.util.ArrayList;
 6 import java.util.List;
 7 
 8 import javax.servlet.http.HttpServletRequest;
 
 9 import javax.servlet.http.HttpServletResponse;
10 
11 import org.apache.http.HttpEntity;
12 import org.apache.http.HttpResponse;
13 import org.apache.http.client.methods.HttpGet;
14 import org.apache.http.impl.client.DefaultHttpClient;
15 import org.apache.http.util.EntityUtils;
16 import org.slf4j.Logger;
 
17 import org.slf4j.LoggerFactory;
18 import org.springframework.stereotype.Controller;
19 import org.springframework.web.bind.annotation.RequestMapping;
20 import org.springframework.web.bind.annotation.ResponseBody;
21 
22 import com.fuyin.mp.utils.GetMenuJson;
23 import com.fuyin.mp.utils.NetWorkHelper;
 
24 import com.fuyin.mp.utils.WxaApi;
25 import com.google.gson.Gson;
26 
27 import net.sf.json.JSONArray;
28 import net.sf.json.JSONObject;
29 
30 @Controller
31 public class WxController {
32     private static final Logger logger = LoggerFactory.getLogger(WxController.class);
33     NetWorkHelper netWorkHelper=new NetWorkHelper();
34     /**
35      * 創建自定義菜單欄
36      */
37     @RequestMapping("creatmenus.action")
38     public String creatmenus(HttpServletRequest req,HttpServletResponse res){
39         logger.debug("自定義菜單欄");
40         NetWorkHelper netWorkHelper=new NetWorkHelper();
41         String u1=WxaApi.CreateMenus.replace("TOKEN", WxaApi.accessToken.getAccessToken());
42         String getruslt = netWorkHelper.getHttpsResponse(u1, "POST", new GetMenuJson().getMenuJson());
43         logger.debug("自定義菜單欄返回結果="+getruslt);
44         return "index.jsp";
45     }
46     
47     /**
48      * 獲取用戶授權
49      */
50     @RequestMapping("Oauth.get")
51     public String Oauth2(HttpServletRequest request,HttpServletResponse response){
52         String newopenid = null;
53         String nickname = null;
54         String city = null;
55         try {
56             logger.debug("授權後的回調請求處理");
57             request.setCharacterEncoding("utf-8");
58             response.setCharacterEncoding("utf-8");
59             // 用戶同意授權後，能獲取到code
60             String code = request.getParameter("code");
61             String state = request.getParameter("state");
62             // 用戶同意授權
63             if (!"authdeny".equals(code)) {
64              //通過code換取網頁授權access_token
65              String reqUrl=WxaApi.codetotoken.replace("APPID", WxaApi.appID).replace("SECRET",WxaApi.appsecret).replace("CODE", code);
66              String httpsResponse = netWorkHelper.getHttpsResponse(reqUrl, "GET", "");
67              logger.debug("用戶授權返回的TOKEN="+httpsResponse);
68              JSONObject jsonObject=JSONObject.fromObject(httpsResponse);
69              String access_token = jsonObject.getString("access_token");
70              String openid = jsonObject.getString("openid");
71              String url=WxaApi.getinfor.replace("ACCESS_TOKEN",access_token).replace("OPENID", openid);
72              JSONObject jsonbject = null;
73              DefaultHttpClient client = new DefaultHttpClient();
74              HttpGet httpget = new HttpGet(url);
75              HttpResponse respone = client.execute(httpget);
76              HttpEntity entity = respone.getEntity();
77              if(entity != null){
78                 String result = EntityUtils.toString(entity,"UTF-8");
79                 jsonbject = JSONObject.fromObject(result);
80                 }
81              newopenid = jsonbject.getString("openid");
82              city = jsonbject.getString("city");
83              nickname = jsonbject.getString("nickname");
84              logger.debug("用戶授權返回的用戶信息="+jsonbject); 
85              nickname = URLEncoder.encode(nickname,"utf-8");
86              System.out.println("openid="+openid+"----nickname="+nickname);
87             }
88             
89         } catch (UnsupportedEncodingException e) {
90             // TODO Auto-generated catch block
91             e.printStackTrace();
92         }catch (IOException e) {
93             // TODO Auto-generated catch block
94             e.printStackTrace();
95         }
96         // 跳轉到index.jsp
97         return "redirect:"+WxaApi.WebUrl+"/demo/main.html?openid="+newopenid+"&nickname="+nickname;
98     }
99 }

授權以後通過重定向，去另一個域名的前端項目裏，以後的交互全是跨域

微信公眾號開發--網頁用戶授權