HttpWebRequest实现下载图片至本地

本文为大家分享了HttpWebRequest实现下载图片至本地的具体代码，供大家参考，具体内容如下

HttpWebRequest发送web请求，获取流文件，保存至本地

using System;
using System.IO;
using System.Net;
using System.Text;
using System.Web.Mvc;
 
namespace Web.Controllers
{
  public class HomeController : Controller
  {
    string url = "http://www.***.com/Image.aspx?ucode=ucode";
 
    public Stream GetFileToStream(string filePath)
    {
      FileStream fileStream = new FileStream(filePath, FileMode.Open, FileAccess.Read, FileShare.Read);
      byte[] bytes = new byte[fileStream.Length];
      fileStream.Read(bytes, 0, bytes.Length);
      fileStream.Close();
      Stream streamFile = new MemoryStream(bytes);
      return streamFile;
    }
 
    public void Method1()
    {
      string fileName = @"upload" + GenerateTimeStamp() + ".jpg";
 
      string webPath = Server.MapPath(fileName);
      string pathName = @"d:" + GenerateTimeStamp() + ".jpg";
      HttpWebRequest req = (HttpWebRequest)WebRequest.Create(url);
 
      req.ServicePoint.Expect100Continue = false;
      req.Method = "GET";
      req.KeepAlive = true;
 
      req.ContentType = "image/png";
      HttpWebResponse rsp = (HttpWebResponse)req.GetResponse();
 
      System.IO.Stream stream = null;
 
      try
      {
 //以字符流的方式读取HTTP响应
 stream = rsp.GetResponseStream();
 System.Drawing.Image.FromStream(stream).Save(pathName);
      }
      finally
      {
 // 释放资源
 if (stream != null) stream.Close();
 if (rsp != null) rsp.Close();
      }
    }
 
    protected void Method2()
    {
      string fileName = @"upload" + GenerateTimeStamp() + ".jpg";
 
      string webPath = Server.MapPath(fileName);
      string pathName = @"d:" + GenerateTimeStamp() + ".jpg";
      HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(url);
      myRequest.Method = "GET";
 
      HttpWebResponse myResponse = null;
      try
      {
 myResponse = (HttpWebResponse)myRequest.GetResponse();
 StreamReader reader = new StreamReader(myResponse.GetResponseStream(), Encoding.UTF8);
 Stream stream = myResponse.GetResponseStream();
 
 #region 保存下载图片
 
 MemoryStream ms = null;
 Byte[] buffer = new Byte[myResponse.ContentLength];
 int offset = 0, actuallyRead = 0;
 do
 {
   actuallyRead = stream.Read(buffer, offset, buffer.Length - offset);
   offset += actuallyRead;
 }
 while (actuallyRead > 0);
 ms = new MemoryStream(buffer);
 
 byte[] buffurPic = ms.ToArray();
 System.IO.File.WriteAllBytes(pathName, buffurPic);
 
 #endregion
      }
      //异常请求
      catch (WebException ex)
      {
 
      }
    }
 
    protected void Method3()
    {
      string fileName = @"upload" + GenerateTimeStamp() + ".jpg";
 
      string webPath = Server.MapPath(fileName);
      string pathName = @"d:" + GenerateTimeStamp() + ".jpg";
      HttpWebRequest myRequest = (HttpWebRequest)WebRequest.Create(url);
      myRequest.Method = "GET";
 
      HttpWebResponse myResponse = null;
      try
      {
 myResponse = (HttpWebResponse)myRequest.GetResponse();
 StreamReader reader = new StreamReader(myResponse.GetResponseStream(), Encoding.UTF8);
 Stream stream = myResponse.GetResponseStream();
 
 #region 保存下载图片
 
 FileStream fileStream = new FileStream(pathName, FileMode.Create, FileAccess.Write);
 byte[] bytes = new byte[1024];
 int readSize = 0;
 while ((readSize = stream.Read(bytes, 0, 1024)) > 0)
 {
   fileStream.Write(bytes, 0, readSize);
   fileStream.Flush();
 }
 #endregion
 
 myResponse.Close();
 stream.Close();
 fileStream.Close();
      }
      //异常请求
      catch (WebException ex)
      {
 
      }
      finally
      {
 
      }
    }
 
    public string GenerateTimeStamp()
    {
      TimeSpan ts = DateTime.UtcNow - new DateTime(1970, 1, 1, 0, 0, 0, 0);
      return Convert.ToInt64(ts.TotalMilliseconds).ToString();
    }
  }
}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持考高分网。