如何使用c#发布JSON到服务器?

下面是我使用的代码:

// create a request
HttpWebRequest request = (HttpWebRequest)
WebRequest.Create(url); request.KeepAlive = false;
request.ProtocolVersion = HttpVersion.Version10;
request.Method = "POST";


// turn our request string into a byte stream
byte[] postBytes = Encoding.UTF8.GetBytes(json);

// this is important - make sure you specify type this way
request.ContentType = "application/json; charset=UTF-8";
request.Accept = "application/json";
request.ContentLength = postBytes.Length;
request.CookieContainer = Cookies;
request.UserAgent = currentUserAgent;
Stream requestStream = request.GetRequestStream();

// now send it
requestStream.Write(postBytes, 0, postBytes.Length);
requestStream.Close();

// grab te response and print it out to the console along with the status code
HttpWebResponse response = (HttpWebResponse)request.GetResponse();
string result;
using (StreamReader rdr = new StreamReader(response.GetResponseStream()))
{
    result = rdr.ReadToEnd();
}

return result;

当我运行这个时，我总是得到500个内部服务器错误。

我做错了什么?

当前回答

HttpClient类型是一个比WebClient和HttpWebRequest更新的实现。WebClient和WebRequest都已被标记为过时。[1]

您可以简单地使用以下几行代码。

string myJson = "{'Username': 'myusername','Password':'pass'}";
using (var client = new HttpClient())
{
    var response = await client.PostAsync(
        "http://yourUrl", 
         new StringContent(myJson, Encoding.UTF8, "application/json"));
}

当你不止一次需要你的HttpClient时，建议只创建一个实例并重用它或使用新的HttpClientFactory。[２]

对于FTP，由于HttpClient不支持，我们建议使用第三方库。

@learn.microsoft.com [3]

从dotnet核心3.1开始，你可以使用System.Text.Json中的JsonSerializer来创建你的json字符串。

string myJson = JsonSerializer.Serialize(credentialsObj);

2018-03-13 22:25:22

其他回答

我的方法是:

var httpWebRequest = (HttpWebRequest)WebRequest.Create("http://url");
httpWebRequest.ContentType = "application/json";
httpWebRequest.Method = "POST";

using (var streamWriter = new StreamWriter(httpWebRequest.GetRequestStream()))
{
    string json = "{\"user\":\"test\"," +
                  "\"password\":\"bla\"}";

    streamWriter.Write(json);
}

var httpResponse = (HttpWebResponse)httpWebRequest.GetResponse();
using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
{
    var result = streamReader.ReadToEnd();
}

我写了一个库来以更简单的方式执行这个任务，它在这里:https://github.com/ademargomes/JsonRequest

2012-04-05 11:15:57

我就是这么做的

//URL
var url = "http://www.myapi.com/";

//Request
using var request = new HttpRequestMessage(HttpMethod.Post, url);

//Headers
request.Headers.Add("Accept", "application/json");
request.Headers.Add("Cache-Control", "no-cache");

//Payload
var payload = JsonConvert.SerializeObject(
    new
    {
        Text = "Hello world"
    });
request.Content = new StringContent(payload, Encoding.UTF8, "application/json");

//Send
var response = await _httpClient.SendAsync(request);

//Handle response
if (response.IsSuccessStatusCode)
    return;

2021-11-15 16:38:48

一些不同的干净的方法是通过使用HttpClient来实现这一点:

public async Task<HttpResponseMessage> PostResult(string url, ResultObject resultObject)
{
    using (var client = new HttpClient())
    {
        HttpResponseMessage response = new HttpResponseMessage();
        try
        {
            response = await client.PostAsJsonAsync(url, resultObject);
        }
        catch (Exception ex)
        {
            throw ex
        }
        return response;
     }
}

2017-06-01 07:09:13

我最终通过包含.Result在同步模式下调用

HttpResponseMessage response = null;
try
{
    using (var client = new HttpClient())
    {
       response = client.PostAsync(
        "http://localhost:8000/....",
         new StringContent(myJson,Encoding.UTF8,"application/json")).Result;
    if (response.IsSuccessStatusCode)
        {
            MessageBox.Show("OK");              
        }
        else
        {
            MessageBox.Show("NOK");
        }
    }
}
catch (Exception ex)
{
    MessageBox.Show("ERROR");
}

2018-02-27 10:34:45

在。net 4.5.1之前，这个选项可以工作:

using (var client = new HttpClient())
{
    client.BaseAddress = new Uri("http://localhost:9000/");
    client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));

    var foo = new User
    {
        user = "Foo",
        password = "Baz"
    }

    await client.PostAsJsonAsync("users/add", foo);
}

2016-09-26 11:29:26

如何使用c#发布JSON到服务器?

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