zoukankan      html  css  js  c++  java
  • (转) C# FileStream复制大文件


                        即每次复制文件的一小段,以节省总内存开销。当然,本机复制也可以采用.NET内部的System.IO.File.Copy方法。

            /// <summary>

            /// 复制文件

            /// </summary>

            /// <param name="fromFile">要复制的文件</param>

            /// <param name="toFile">要保存的位置</param>

            /// <param name="lengthEachTime">每次复制的长度</param>

            private void CopyFile(string fromFile, string toFile, int lengthEachTime)

            {

                FileStream fileToCopy = new FileStream(fromFile, FileMode.Open, FileAccess.Read);

                FileStream copyToFile = new FileStream(toFile, FileMode.Append, FileAccess.Write);

                int lengthToCopy;

                if (lengthEachTime < fileToCopy.Length)//如果分段拷贝,即每次拷贝内容小于文件总长度

                {

                    byte[] buffer = new byte[lengthEachTime];

                    int copied = 0;

                    while (copied <= ((int)fileToCopy.Length - lengthEachTime))//拷贝主体部分

                    {

                        lengthToCopy = fileToCopy.Read(buffer, 0, lengthEachTime);

                        fileToCopy.Flush();

                        copyToFile.Write(buffer, 0, lengthEachTime);

                        copyToFile.Flush();

                        copyToFile.Position = fileToCopy.Position;

                        copied += lengthToCopy;

                    }

                    int left = (int)fileToCopy.Length - copied;//拷贝剩余部分

                    lengthToCopy = fileToCopy.Read(buffer, 0, left);

                    fileToCopy.Flush();

                    copyToFile.Write(buffer, 0, left);

                    copyToFile.Flush();

                }

                else//如果整体拷贝,即每次拷贝内容大于文件总长度

                {

                    byte[] buffer = new byte[fileToCopy.Length];

                    fileToCopy.Read(buffer,0,(int)fileToCopy.Length);

                    fileToCopy.Flush();

                    copyToFile.Write(buffer, 0, (int)fileToCopy.Length);

                    copyToFile.Flush();

                }

                fileToCopy.Close();

                copyToFile.Close();

            }

  • 相关阅读:
    服务端实现url网页截屏、HTML保存为高质量PDF[puppeteer]
    网页保存为图片[rasterizeHTML]
    SortedList<T,K>,SortedDictionary<T,K>,Dictionay<T,K>用法区别
    svn实现类似git stash及git stash pop的功能
    MSBuild报错及找不到AxImp.exe或LC.exe问题
    记一个ios下text-overflow: ellipsis 与 text-align: justify 冲突的问题
    Chrome devtools inspect后打开空白解决办法
    Oracle长时间使用导致连接变慢且频繁报无法找到监听程序的错误
    vscode+vue不得不用的插件和不得不添加的配置
    初识vscode+vue
  • 原文地址:https://www.cnblogs.com/yangxiaohu1/p/1226949.html
Copyright © 2011-2022 走看看