js檔案複製 note

**:

//資料的分批寫入

let fs =
require
('fs');
let path =
require
('path');
//1.生成讀取和寫入的路徑
let readpath = path.
join
(__dirname,
"test.mp4");
let writepath = path.
join
(__dirname,
"abc.mp4");
//第一種複製方式
/*//2.建立乙個讀取流
let readstream = fs.createreadstream(readpath);
//3.建立乙個寫入流
let writestream = fs.createwritestream(writepath);
//4.監聽讀取流的事件
readstream.on("open", function () );
readstream.on("error", function () );
readstream.on("data", function (data) );
readstream.on("close", function () );
//5.監聽寫入流的事件
writestream.on("open", function () );
writestream.on("error", function () );
writestream.on("close", function () );*/
//第二種方式,管道符複製：
//2.建立乙個讀取流
let readstream = fs.
createreadstream
(readpath)
;//3.建立乙個寫入流
let writestream = fs.
createwritestream
(writepath)
;//利用讀取流的管道方法實現快速檔案拷貝,內部的實現其實就是上面的寫法
readstream.
pipe
(writestream)
;

檔案大小無誤

第二種方式複製

大小無誤

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