API请求接口-远程服务器返回错误: (400) 错误的请求错误_request.getresponse()远程服务器返回错误: (400) 错误的请求。-优快云博客

这个博客主要展示了如何使用C#进行HTTP Web请求，特别是在遇到异常时如何捕获并处理错误。代码示例中，作者创建了一个静态方法`HttpWebRequest`，用于发送POST请求，并在出现WebException时从响应中读取可能存在的数据。该方法包含了错误处理逻辑，以确保即使在异常情况下也能获取到服务器的响应信息。

捕获异常查看具体错误

using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.ComponentModel.DataAnnotations;
using System.IO;
using System.Net;
using System.Reflection;
using System.Text;

namespace Test
{

    class Program
    {

        static void Main(string[] args)
        {
            string url = "http://www.baidus.com";
            string contentType = "application/x-www-form-urlencoded";
            int timeOut = 3000;
            string parms = "626";
            int encoding = 65001;
            HttpWebRequest(url, parms, encoding, contentType, timeOut);
        }

        public static void HttpWebRequest(string url, string parms, int encoding, string contentType = "application/x-www-form-urlencoded", int timeOut = 3000)
        {
            try
            {
                string result = string.Empty;
                var mRequest = (HttpWebRequest)WebRequest.Create(url);
                //相应请求的参数
                var data = Encoding.GetEncoding(encoding).GetBytes(parms);
                mRequest.Method = "Post";
                mRequest.ContentType = contentType;
                mRequest.ContentLength = data.Length;
                mRequest.Timeout = timeOut;
                mRequest.KeepAlive = true;
                mRequest.ProtocolVersion = HttpVersion.Version10;
                //请求流
                var requestStream = mRequest.GetRequestStream();
                requestStream.Write(data, 0, data.Length);
                requestStream.Close();
                //响应流
                var mResponse = mRequest.GetResponse() as HttpWebResponse;//此位置进入catch(403)
                var responseStream = mResponse.GetResponseStream();//
                if (responseStream != null)
                {
                    var streamReader = new StreamReader(responseStream, Encoding.GetEncoding(encoding));
                    //获取返回的信息
                    result = streamReader.ReadToEnd();
                    streamReader.Close();
                    responseStream.Close();
                }
            }
            catch (System.Net.WebException ex)
            { //进入异常   在异常里获取  返回的数据，有时候在调试的时候 直接异常进入这里，我们得不到数据，
              //如果用Fiddler我们查看访问的结果是有数据的，经过下面的处理，最终得到数据
                string result = string.Empty;
                //响应流
                var mResponse = ex.Response as HttpWebResponse;
                var responseStream = mResponse.GetResponseStream();
                if (responseStream != null)
                {
                    var streamReader = new StreamReader(responseStream, Encoding.GetEncoding(encoding));
                    //获取返回的信息
                    result = streamReader.ReadToEnd();
                    streamReader.Close();
                    responseStream.Close();
                }
                result = "获取数据失败，请重试！" + url + ex.ToString() + "         返回数据" + result;
            }
        }

    }

}