如何调用外部的Web API

1. Uri uri = new Uri(url + "?" + postData);
2. System.Net.HttpWebRequest request = (System.Net.HttpWebRequest)System.Net.WebRequest.Create(uri);
3. request.Method = "GET";
4. request.ContentType = "application/x-www-form-urlencoded";
5. request.AllowAutoRedirect = false;
6. request.Timeout = 5000;
7. System.Net.HttpWebResponse response = (System.Net.HttpWebResponse)request.GetResponse();
8. Stream responseStream = response.GetResponseStream();
9. StreamReader readStream = new StreamReader(responseStream, System.Text.Encoding.UTF8);
10. string retext = readStream.ReadToEnd().ToString();
11. readStream.Close();
12. return retext;
13. }