如何以编程方式保存来自 URL 的图像？

Question

如何以编程方式保存来自 URL 的图像？我正在使用 C#，需要能够从 URL 中获取图像并将它们存储在本地。 ...不，我不是在偷东西 :)

Answer 1

我的解决方案是将图像预先保存到磁盘，然后作为普通保存的图像使用：

remoteFile = "http://xxx.yyy.com/image1.png"; localFile = "c:\myimage.png";

WebClient webClient = new WebClient(); webClient.DownloadFile(remoteFile, localFile);

Answer 2

aspx (c#) 中的一个例子

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Net;
using System.IO;

public partial class download_file_from_url : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        string url = "http://4rapiddev.com/wp-includes/images/logo.jpg";
        string file_name = Server.MapPath(".") + "\\logo.jpg";

        save_file_from_url(file_name, url);

        Response.Write("The file has been saved at: " + file_name);
    }

    public void save_file_from_url(string file_name, string url)
    {
        byte[] content;
        HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
        WebResponse response = request.GetResponse();

        Stream stream = response.GetResponseStream();

        using (BinaryReader br = new BinaryReader(stream))
        {
            content = br.ReadBytes(500000);
            br.Close();
        }
        response.Close();

        FileStream fs = new FileStream(file_name, FileMode.Create);
        BinaryWriter bw = new BinaryWriter(fs);
        try
        {
            bw.Write(content);
        }
        finally
        {
            fs.Close();
            bw.Close();
        }
    }
}

作者：HOAN HUYNH
ASP.Net C# Download Or Save Image File From URL

Answer 3

这样写会更容易：

WebClient webClient = new WebClient();
webClient.DownloadFile(remoteFileUrl, localFileName);

Answer 4

您只需使用 HttpWebRequest 为图像的 URI 发出基本的 http 请求，然后获取生成的字节流，然后将该流保存到文件中。

这是一个关于如何执行此操作的示例...

'作为旁注，如果图像非常大，您可能希望将 br.ReadBytes(500000) 分解为一个循环，并在写入每批字节时一次抓取 n 个字节找回它们。'

using System;
using System.IO;
using System.Net;
using System.Text;

namespace ImageDownloader
{
    class Program
    {
        static void Main(string[] args)
        {
            string imageUrl = @"http://www.somedomain.com/image.jpg";
            string saveLocation = @"C:\someImage.jpg";

            byte[] imageBytes;
            HttpWebRequest imageRequest = (HttpWebRequest)WebRequest.Create(imageUrl);
            WebResponse imageResponse = imageRequest.GetResponse();

            Stream responseStream = imageResponse.GetResponseStream();

            using (BinaryReader br = new BinaryReader(responseStream ))
            {
                imageBytes = br.ReadBytes(500000);
                br.Close();
            }
            responseStream.Close();
            imageResponse.Close();

            FileStream fs = new FileStream(saveLocation, FileMode.Create);
            BinaryWriter bw = new BinaryWriter(fs);
            try
            {
                bw.Write(imageBytes);
            }
            finally
            {
                fs.Close();
                bw.Close();
            }
        }
    }
}