通过参数与凌空后

Question

我能够使用Postman和以下参数调用HTTPendpoint：

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

但是，我无法通过Android对截击进行同样的操作：这里尝试使用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);

这里是尝试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，会发出调用，但不会传递任何参数；当我使用StringRequest时，会出现以下错误？如何将JSON数据传递给Volley调用？

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

以下是处理请求的服务器代码

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; }
}

Answer 1

您正在使用params。用put代替params2。在传递参数时放入哈希映射。因为您的对象名是params2

Answer 2

在标题中添加内容类型

@Override
public Map<String, String> getHeaders() throws AuthFailureError {
HashMap<String, String> headers = new HashMap<String, String>();
headers.put("Content-Type", "application/json; charset=utf-8");
return headers;
}    

Answer 3

服务器代码期望JSON对象返回字符串，而不是JSON字符串。

JSONObject请求

JSONRequest在请求正文中发送一个JSON对象，并期望响应中有一个JSON对象。由于服务器返回一个字符串，它最终会抛出ParseError

StringRequest

StringRequest发送主体类型为x-www-form-urlencoded的请求，但因为服务器需要JSON对象。你最终收到了400个错误的请求

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JSON对象。因为它已经期待一个字符串，所以你的响应很好。代码应该如下。

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";
    }
};

服务器代码中也有一个错误

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

应该是

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