解決問題 

正確：

 {

 "data":

{accesstoken : "odA5niNeOhhi1cIK0eOGhrxCB7ClG9R4gl%2Fa2%2FNcOaJ42tWayXKZZZBgIPsh1tRLshlxWyXlEyY...",

 expirein :"2017-11-27 14:49:23"

},

     "flag":1,

    "success":1,

     "expired":0

  }

錯誤：

 {

 flag:1,

 expired :0,

success : 0,

 err :{

          code :"xxx",

         Msg :"密碼錯誤"

      }

 }

import com.alibaba.fastjson.JSONObject;
import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
import com.lenovo.pcsd.bp.businesspartner.bean.UserModel;
import okhttp3.*;

import java.util.HashMap;
import java.util.Map;


public class HttpUtils {
    public static Map post(String url,Object obj){
        //建立連線客戶端
        OkHttpClient client = new OkHttpClient();
        //使用Gson 新增 依賴 compile 'com.google.code.gson:gson:2.8.1'
        Gson gson = new Gson();
        //使用Gson將物件轉換為json字串
        String json = gson.toJson(obj);
        //MediaType  設定Content-Type 標頭中包含的媒體型別值
        RequestBody requestBody = FormBody.create(MediaType.parse("application/json; charset=utf-8")
                , json);
        Request request = new Request.Builder()
                .url(url)//請求的url
                .post(requestBody)
                .build();
        Call call = client.newCall(request);
        Response response;//執行
        {
            try {
                response = call.execute();
                if (response.isSuccessful()) {
                    String result=response.body().string();
                    Map<String,String> resultMap=new HashMap<String, String>();
                    if(JSONObject.parseObject(result).get("success").equals(1)){
                        JSONObject object = JSONObject.parseObject(result).getJSONObject("data");
                        String accesstoken= (String) object.get("accesstoken");
                        String expirein= (String) object.get("expirein");
                        resultMap.put("success","1");
                        resultMap.put("accesstoken",accesstoken);
                        resultMap.put("expirein",expirein);
                    }else {
                        String errCode = (String) JSONObject.parseObject(result).getJSONObject("err").get("code");
                        String errMsg = (String) JSONObject.parseObject(result).getJSONObject("err").get("msg");
                        resultMap.put("success","0");
                        resultMap.put("errCode",errCode);
                        resultMap.put("errMsg",errMsg);
                    }
                    return resultMap;
                }

            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return null;
    }

}