HttpWebRequest上传多文件和多参数——整理

1.整理HttpWebRequest上传多文件和多参数。较上一个版本，更具普适性和简易型。注意（服务方web.config中要配置）这样就可以上传大文件了

<system.webServer>
      <requestFiltering>
        <requestLimits maxAllowedContentLength="4294967295" />
      </requestFiltering>
</system.webServer>
<system.web>
    <httpRuntime  maxRequestLength="2048000"/>
</system.web>

2.HttpWebRequest的封装

/// <summary>
  /// Http上传文件类 - HttpWebRequest封装
  /// </summary>
  public class HttpUploadClient
  {
      public static string ExecuteMultipartRequest(string url, List<KeyValue> nvc)
      {
          string boundary = "---------------------------" + DateTime.Now.Ticks.ToString("x");
          byte[] boundarybytes = Encoding.UTF8.GetBytes("\r\n--" + boundary + "\r\n");
 
          HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create(new Uri(url, UriKind.RelativeOrAbsolute));
          webRequest.Method = "POST";
          webRequest.Timeout = 1800000;
          webRequest.ContentType = "multipart/form-data; boundary=" + boundary;
          webRequest.KeepAlive = true;
          webRequest.Credentials = System.Net.CredentialCache.DefaultCredentials;
          using (var rs = webRequest.GetRequestStream())
          {
              // 普通参数模板
              string formdataTemplate = "Content-Disposition: form-data; name=\"{0}\"\r\n\r\n{1}";
              //带文件的参数模板
              string headerTemplate = "Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\nContent-Type: {2}\r\n\r\n";
              foreach (KeyValue keyValue in nvc)
              {
                  //如果是普通参数
                  if (keyValue.FilePath == null)
                  {
                      rs.Write(boundarybytes, 0, boundarybytes.Length);
                      string formitem = string.Format(formdataTemplate, keyValue.Key, keyValue.Value);
                      byte[] formitembytes = System.Text.Encoding.UTF8.GetBytes(formitem);
                      rs.Write(formitembytes, 0, formitembytes.Length);
                  }
                  //如果是文件参数,则上传文件
                  else
                  {
                      rs.Write(boundarybytes, 0, boundarybytes.Length);
                      string header = string.Format(headerTemplate, keyValue.Key, keyValue.Value, keyValue.ContentType);
                      byte[] headerbytes = System.Text.Encoding.UTF8.GetBytes(header);
                      rs.Write(headerbytes, 0, headerbytes.Length);
                      using (var fileStream = new FileStream(keyValue.FilePath, FileMode.Open, FileAccess.Read))
                      {
                          byte[] buffer = new byte[4096];
                          int bytesRead = 0;
                          long total = 0;
                          while ((bytesRead = fileStream.Read(buffer, 0, buffer.Length)) != 0)
                          {
                              rs.Write(buffer, 0, bytesRead);
                              total += bytesRead;
                          }
                      }
                  }
 
              }
              byte[] trailer = Encoding.UTF8.GetBytes("\r\n--" + boundary + "--\r\n");
              rs.Write(trailer, 0, trailer.Length);
              rs.Close();
          }
 
          // 获取响应
          using (HttpWebResponse webResponse = (HttpWebResponse)webRequest.GetResponse())
          {
              using (StreamReader reader = new StreamReader(webResponse.GetResponseStream(), Encoding.UTF8))
              {
                  string body = reader.ReadToEnd();
                  reader.Close();
                  return body;
              }
          }
      }

3.参数封装（支持普通参数和多文件）

public class KeyValue
  {
      public string Key;
      public string Value;
      public string FilePath;
      public string ContentType = "*/*";
      public KeyValue(string key, string value, string filePath, string contentType)
      {
          Key = key;
          Value = value;
          FilePath = filePath;
          ContentType = contentType;
      }
      public KeyValue() { }
      public KeyValue(string key, string value, string filePath)
      {
          Key = key;
          Value = value;
          FilePath = filePath;
      }
      public KeyValue(string key, string value)
      {
          Key = key;
          Value = value;
      }
  }

4.调用示例

List<KeyValue> keyValues = new List<KeyValue>();
keyValues.Add(new KeyValue("key1", "12_423232523"));
keyValues.Add(new KeyValue("key2", " 1 2 3"));
keyValues.Add(new KeyValue("file1", "1.img", @"C:\临时\tempDB\1.img"));
keyValues.Add(new KeyValue("file2", "2.xls", @"C:\临时\tempDB\2.xls"));
HttpUploadClient.ExecuteMultipartRequest(url, keyValues);

5.服务接收方示例

for (int i = 0; i < HttpContext.Current.Request.Files.Count; i++)
{
     HttpPostedFile file = HttpContext.Current.Request.Files[i];
     file.SaveAs(""+file.FileName);
}
string Params = HttpContext.Current.Request.Form["key1"];