C# Response如何处理大文件下载
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在C#中处理大文件下载通常需要考虑以下几个方面:
1、使用流(Stream)来处理大文件下载,可以有效避免一次性加载整个文件到内存中,节约内存资源。可以使用HttpWebRequest或HttpClient来获取文件的流,然后逐块下载文件内容。
using System; using System.IO; using System.Net; public class FileDownloader { public void DownloadFile(string url, string savePath) { using (var client = new WebClient()) { using (var stream = client.OpenRead(url)) { using (var fileStream = new FileStream(savePath, FileMode.Create)) { byte[] buffer = new byte[4096]; int bytesRead; while ((bytesRead = stream.Read(buffer, 0, buffer.Length)) > 0) { fileStream.Write(buffer, 0, bytesRead); } } } } } }
2、使用异步下载来提高下载性能,可以使用HttpClient的异步方法来下载文件。
using System; using System.IO; using System.Net.Http; using System.Threading.Tasks; public class FileDownloader { public async Task DownloadFileAsync(string url, string savePath) { using (var client = new HttpClient()) { using (var stream = await client.GetStreamAsync(url)) { using (var fileStream = new FileStream(savePath, FileMode.Create)) { await stream.CopyToAsync(fileStream); } } } } }
3、考虑断点续传功能,可以在下载过程中记录已经下载的文件大小,以便在下载中断后可以继续下载。
public class FileDownloader { public async Task DownloadFileWithResumeAsync(string url, string savePath) { long fileSize = 0; if (File.Exists(savePath)) { fileSize = new FileInfo(savePath).Length; } using (var client = new HttpClient()) { var request = new HttpRequestMessage(HttpMethod.Get, url); request.Headers.Range = new System.Net.Http.Headers.RangeHeaderValue(fileSize, null); using (var response = await client.SendAsync(request, HttpCompletionOption.ResponseHeadersRead)) { using (var stream = await response.Content.ReadAsStreamAsync()) { using (var fileStream = new FileStream(savePath, FileMode.Append)) { await stream.CopyToAsync(fileStream); } } } } } }