本篇文章为大家展示了使用HttpWebRequest怎么下载图片至本地，内容简明扼要并且容易理解，绝对能使你眼前一亮，通过这篇文章的详细介绍希望你能有所收获。
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();
}
}
}上述内容就是使用HttpWebRequest怎么下载图片至本地，你们学到知识或技能了吗？如果还想学到更多技能或者丰富自己的知识储备，欢迎关注创新互联成都网站设计公司行业资讯频道。
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