.NET Core(C#) POST JSON数据和Form表单的方法及示例代码

1､POST提交JSON格式数据

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();}

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2､POST提交Form表单数据

1) type为"application/x-www-form-urlencoded"类型的表单

/// 
/// 执行POST请求/// 
/// /// /// application/xml、application/json、application/text、application/x-www-form-urlencoded/// 填充消息头        /// public static string HttpPost(string url, string paramData, Dictionary headers = null, string contentType = "application/json", int timeOut = 30){    using (HttpClient client = new HttpClient())    {        if (headers != null)        {            foreach (var header in headers)                client.DefaultRequestHeaders.Add(header.Key, header.Value);        }        using (HttpContent httpContent = new StringContent(paramData, Encoding.UTF8))        {            if (contentType != null)                httpContent.Headers.ContentType = new System.Net.Http.Headers.MediaTypeHeaderValue(contentType);            HttpResponseMessage response = client.PostAsync(url, httpContent).Result;            return response.Content.ReadAsStringAsync().Result;        }    }}

2) type为"multipart/form-data"类型的表单

public async Task UploadFile(string filePath){    if (string.IsNullOrWhiteSpace(filePath))    {        throw new ArgumentNullException(nameof(filePath));    }    if (!File.Exists(filePath))    {        throw new FileNotFoundException($"File [{filePath}] not found.");    }    using var form = new MultipartFormDataContent();    using var fileContent = new ByteArrayContent(await File.ReadAllBytesAsync(filePath));    fileContent.Headers.ContentType = MediaTypeHeaderValue.Parse("multipart/form-data");    form.Add(fileContent, "file", Path.GetFileName(filePath));    //表单中其它参数    form.Add(new StringContent("789"), "userId");    form.Add(new StringContent("some comments"), "comment");    form.Add(new StringContent("true"), "isPrimary");    var response = await _httpClient.PostAsync($"{_url}/api/files", form);    response.EnsureSuccessStatusCode();    var responseContent = await response.Content.ReadAsStringAsync();    var result = JsonSerializer.Deserialize(responseContent);    _logger.LogInformation("Uploading is complete.");    return result.Guid;}

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