如何使用C＃将JSON发布到服务器？

这是我正在使用的代码：

// 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;

当我运行此命令时，总是会收到500个内部服务器错误。

我究竟做错了什么？

我这样做并且正在工作的方式是：

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();
}

我编写了一个库以更简单的方式执行此任务，它在这里：https : //github.com/ademargomes/JsonRequest

希望能帮助到你。

通过利用JavaScriptSerializer的Serialize方法可以将对象隐式转换为JSON，从而可以改善Ademar的解决方案。

另外，可以利用using语句的默认功能来省略显式调用Flushand Close。

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

using (var streamWriter = new StreamWriter(httpWebRequest.GetRequestStream()))
{
    string json = new JavaScriptSerializer().Serialize(new
                {
                    user = "Foo",
                    password = "Baz"
                });

    streamWriter.Write(json);
}

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

该HttpClient类型比WebClient和的实现要新HttpWebRequest。

您可以简单地使用以下几行。

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"));
}

如果您需要HttpClient多个实例，建议仅创建一个实例并重用它或使用new HttpClientFactory。

在Sean的帖子之后，没有必要嵌套using语句。通过usingStreamWriter，它将在块的末尾刷新并关闭，因此无需显式调用Flush()和Close()方法：

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

using (var streamWriter = new StreamWriter(request.GetRequestStream()))
{
    string json = new JavaScriptSerializer().Serialize(new
                {
                    user = "Foo",
                    password = "Baz"
                });

    streamWriter.Write(json);
}

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

如果您需要异步调用，请使用

var request = HttpWebRequest.Create("http://www.maplegraphservices.com/tokkri/webservices/updateProfile.php?oldEmailID=" + App.currentUser.email) as HttpWebRequest;
            request.Method = "POST";
            request.ContentType = "text/json";
            request.BeginGetRequestStream(new AsyncCallback(GetRequestStreamCallback), request);

private void GetRequestStreamCallback(IAsyncResult asynchronousResult)
    {
        HttpWebRequest request = (HttpWebRequest)asynchronousResult.AsyncState;
        // End the stream request operation

        Stream postStream = request.EndGetRequestStream(asynchronousResult);


        // Create the post data
        string postData = JsonConvert.SerializeObject(edit).ToString();

        byte[] byteArray = Encoding.UTF8.GetBytes(postData);


        postStream.Write(byteArray, 0, byteArray.Length);
        postStream.Close();

        //Start the web request
        request.BeginGetResponse(new AsyncCallback(GetResponceStreamCallback), request);
    }

    void GetResponceStreamCallback(IAsyncResult callbackResult)
    {
        HttpWebRequest request = (HttpWebRequest)callbackResult.AsyncState;
        HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(callbackResult);
        using (StreamReader httpWebStreamReader = new StreamReader(response.GetResponseStream()))
        {
            string result = httpWebStreamReader.ReadToEnd();
            stat.Text = result;
        }

    }

照顾您正在使用的Content-Type：

application/json

资料来源：

RFC4627

其他职位

我最近想出了一种发布JSON的简单得多的方法，另外还有从我的应用程序中的模型进行转换的步骤。请注意，必须为控制器创建模型[JsonObject]以获取值并进行转换。

请求：

 var model = new MyModel(); 

 using (var client = new HttpClient())
 {
     var uri = new Uri("XXXXXXXXX"); 
     var json = new JavaScriptSerializer().Serialize(model);
     var stringContent = new StringContent(json, Encoding.UTF8, "application/json");
     var response = await Client.PutAsync(uri,stringContent).Result;
     ...
     ...
  }

模型：

[JsonObject]
[Serializable]
public class MyModel
{
    public Decimal Value { get; set; }
    public string Project { get; set; }
    public string FilePath { get; set; }
    public string FileName { get; set; }
}

服务器端：

[HttpPut]     
public async Task<HttpResponseMessage> PutApi([FromBody]MyModel model)
{
    ...
    ... 
}

未提及此选项：

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);
}

实现此目标的一些不同且干净的方法是使用HttpClient，如下所示：

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;
     }
}

警告！在这个问题上，我有很强烈的看法。

.NET的现有Web客户端对开发人员不友好！ WebRequest和WebClient是“如何挫败开发人员”的主要示例。它们冗长而复杂。当您要做的只是在C＃中执行一个简单的Post请求。HttpClient可以解决这些问题，但是仍然不足。最重要的是，Microsoft的文档很糟糕……确实很糟糕；除非您要浏览技术性页面和页面。

开源拯救。有三种出色的开源免费NuGet库可供选择。谢天谢地！这些都得到很好的支持和记录，是的，很容易-纠正...超级容易-可以使用。

• ServiceStack.Text-快速，轻便和灵活。
• RestSharp简单的REST和HTTP API客户端
• Flurl-一个流畅，可移植，可测试的HTTP客户端库

它们之间没有太多，但是我会给ServiceStack.Text带来一点优势……

• Github的星星大致相同。
• 未解决的问题，重要的是，任何问题关闭的速度有多快？ServiceStack在这里以最快的问题解决速度和没有未解决的问题获得奖项。
• 文档？所有人都有很好的文档。但是，ServiceStack将其提升到一个新的水平，并以其“黄金标准”而闻名。

好的-在ServiceStack.Text中，JSON中的Post Request看起来如何？

var response = "http://example.org/login"
    .PostJsonToUrl(new Login { Username="admin", Password="mypassword" });

那是一行代码。简洁易用！将以上内容与.NET的Http库进行比较。

我终于通过包含.Result在同步模式下调用了

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");
}

var data = Encoding.ASCII.GetBytes(json);

byte[] postBytes = Encoding.UTF8.GetBytes(json);

使用ASCII代替UFT8