Gson：预计BEGIN_OBJECT但是在第1行第1列路径$ STRING

Question

Java代码：

 Gson gson = new GsonBuilder().setLenient().create();
    OkHttpClient client = new OkHttpClient();
    Retrofit retrofit = new Retrofit.Builder()
            .baseUrl(Constants.BASE_URL)
            .client(client)
            .addConverterFactory(GsonConverterFactory.create(gson))
            .build();

    RequestInterface requestInterface = retrofit.create(RequestInterface.class);

    User user = new User();
    user.setEmail(email);
    user.setPassword(password);
    ServerRequest request = new ServerRequest();
    request.setOperation(Constants.LOGIN_OPERATION);
    request.setUser(user);
    Call<ServerResponse> response = requestInterface.operation(request);

    response.enqueue(new Callback<ServerResponse>() {
        @Override
        public void onResponse(Call<ServerResponse> call, retrofit2.Response<ServerResponse> response) {

            ServerResponse resp = response.body();
            Snackbar.make(getView(), resp.getMessage(), Snackbar.LENGTH_LONG).show();

            if(resp.getResult().equals(Constants.SUCCESS)){
                SharedPreferences.Editor editor = pref.edit();
                editor.putBoolean(Constants.IS_LOGGED_IN,true);
                editor.putString(Constants.EMAIL,resp.getUser().getEmail());
                editor.putString(Constants.NAME,resp.getUser().getName());
                //editor.putString(Constants.UNIQUE_ID,resp.getUser().getUnique_id());
                editor.apply();
                goToProfile();

            }
            progress.setVisibility(View.INVISIBLE);
        }

        @Override
        public void onFailure(Call<ServerResponse> call, Throwable t) {

            progress.setVisibility(View.INVISIBLE);
            Log.d(Constants.TAG,"failed");
            Snackbar.make(getView(), t.getLocalizedMessage(), Snackbar.LENGTH_LONG).show();

        }
    });
}

JSON：

{"user":{"name":"Tan Jin","email":"ligo1995tan@gmail.com"},"result":"success","message":"Login Successful"}

当我运行app时，出现错误。我不知道为什么？救命！但是我收到一条错误消息：

  

com.google.gson.JsonSyntaxException：java.lang.IllegalStateException：预期为BEGIN_OBJECT，但在第1行第1行路径为STRING