使用 Volley POST 传递参数 [英] Pass Parameter with Volley POST

问题描述

我能够使用 Postman 和这些参数调用 HTTP 端点:

I was able to call an HTTP endpoint using Postman and these parameters:

{
    "name":"Val",
    "subject":"Test"
}

但是我无法通过 Android 对 Volley 做同样的事情:这里正在尝试使用 JSONRequest:

However I am unable to do the same with Volley through Android: Here is trying to use JSONRequest:

HashMap<String, String> params2 = new HashMap<String, String>();
        params.put("name", "Val");
        params.put("subject", "Test Subject");

        JsonObjectRequest jsObjRequest = new JsonObjectRequest
                (Request.Method.POST, Constants.CLOUD_URL, new JSONObject(params2), new Response.Listener<JSONObject>() {

                    @Override
                    public void onResponse(JSONObject response) {
                        mView.showMessage("Response: " + response.toString());
                    }
                }, new Response.ErrorListener() {

                    @Override
                    public void onErrorResponse(VolleyError error) {
                        // TODO Auto-generated method stub
                        mView.showMessage(error.getMessage());

                    }
                });

        // Access the RequestQueue through your singleton class.
        VolleySingleton.getInstance(mContext).addToRequestQueue(jsObjRequest);

这里正在尝试 StringRequest

And here is trying StringRequest

private void postMessage(Context context, final String name, final String subject ){

        RequestQueue queue = Volley.newRequestQueue(context);
        StringRequest sr = new StringRequest(Request.Method.POST, Constants.CLOUD_URL, new Response.Listener<String>() {
            @Override
            public void onResponse(String response) {
                mView.showMessage(response);
            }
        }, new Response.ErrorListener() {
            @Override
            public void onErrorResponse(VolleyError error) {

            }
        }){
            @Override
            protected Map<String,String> getParams(){
                Map<String,String> params = new HashMap<String, String>();
                params.put("name", name);
                params.put("subject", subject);

                return params;
            }

            @Override
            public Map<String, String> getHeaders() throws AuthFailureError {
                Map<String,String> params = new HashMap<String, String>();
                params.put("Content-Type","application/x-www-form-urlencoded");
                return params;
            }
        };
        queue.add(sr);
    }

当我使用 JSONRequest 时，调用 POSTs 但没有传递参数，当我使用 StringRequest 时，我收到以下错误?如何将 JSON 数据传递给 Volley 调用?

When I use JSONRequest, the call POSTs but no parameter is passed and when I use StringRequest I get the error below? How can I pass JSON data to Volley call?

E/Volley: [13053] BasicNetwork.performRequest: Unexpected response code 400 for 

这里是处理请求的服务器代码

Here is the server code that handles the request

public static async Task<HttpResponseMessage> Run(HttpRequestMessage req, TraceWriter log)
{
    var helloRequest = await req.Content.ReadAsAsync<HelloRequest>();

    var name = helloRequest?.Name ?? "world";    
    var responseMessage = $"Hello {personToGreet}!";


    log.Info($"Message: {responseMessage}");


    return req.CreateResponse(HttpStatusCode.OK, $"All went well.");
}

public class HelloRequest
{
    public string Name { get; set; }
    public string Subject { get; set; }
}

推荐答案

服务器代码期望 JSON 对象返回字符串或 Json 字符串.

The server code is expecting a JSON object is returning string or rather Json string.

JsonObjectRequest

JSONRequest 在请求正文中发送一个 JSON 对象，并在响应中期望一个 JSON 对象.由于服务器返回一个字符串，它最终会抛出 ParseError

JSONRequest sends a JSON object in the request body and expects a JSON object in the response. Since the server returns a string it ends up throwing ParseError

StringRequest

StringRequest 发送一个主体类型为 x-www-form-urlencoded 的请求，但因为服务器需要一个 JSON 对象.您最终会收到 400 个错误请求

StringRequest sends a request with body type x-www-form-urlencoded but since the server is expecting a JSON object. You end up getting 400 Bad Request

解决方案

解决方案是将字符串请求中的内容类型更改为 JSON，并在正文中传递一个 JSON 对象.因为它已经期待一个字符串，你回应你在那里很好.代码如下.

The Solution is to change the content-type in the string request to JSON and also pass a JSON object in the body. Since it already expects a string you response you are good there. Code for that should be as follows.

StringRequest sr = new StringRequest(Request.Method.POST, Constants.CLOUD_URL, new Response.Listener<String>() {
    @Override
    public void onResponse(String response) {
        mView.showMessage(response);
    }
}, new Response.ErrorListener() {
    @Override
    public void onErrorResponse(VolleyError error) {
        mView.showMessage(error.getMessage());
    }
}) {
    @Override
    public byte[] getBody() throws AuthFailureError {
        HashMap<String, String> params2 = new HashMap<String, String>();
        params2.put("name", "Val");
        params2.put("subject", "Test Subject");
        return new JSONObject(params2).toString().getBytes();
    }

    @Override
    public String getBodyContentType() {
        return "application/json";
    }
};

这里的服务器代码也有一个错误

Also there is a bug here in the server code

var responseMessage = $"Hello {personToGreet}!";

应该

var responseMessage = $"Hello {name}!";

这篇关于使用 Volley POST 传递参数的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！