var fs = require('fs');var readStream = fs.createReadStream('/path/to/source');var writeStream = fs.createWriteStream('/path/to/dest');

readStream.on('data', function(chunk) { // 當(dāng)有數(shù)據(jù)流出時(shí)，寫(xiě)入數(shù)據(jù)
? ?writeStream.write(chunk);
});

readStream.on('end', function() { // 當(dāng)沒(méi)有數(shù)據(jù)時(shí)，關(guān)閉數(shù)據(jù)流
? ?writeStream.end();
});

上面的代碼就有一個(gè)問(wèn)題，要是寫(xiě)入速度跟不上讀取速度，就可能造成你說(shuō)的writeStream還沒(méi)寫(xiě)完就被關(guān)閉了。所以可以改成下面這種，我寫(xiě)完一段，你再讀取下一段。這里如果是最后一次讀取數(shù)據(jù)，那么讀了之后，writeStream開(kāi)始寫(xiě)，寫(xiě)完再通知readStream去讀數(shù)據(jù)，可是這時(shí)readStream發(fā)現(xiàn)沒(méi)有數(shù)據(jù)可讀了，于是就觸發(fā)end事件的監(jiān)聽(tīng)器，它們才被關(guān)閉了

var fs = require('fs');var readStream = fs.createReadStream('/path/to/source');var writeStream = fs.createWriteStream('/path/to/dest');

readStream.on('data', function(chunk) { // 當(dāng)有數(shù)據(jù)流出時(shí)，寫(xiě)入數(shù)據(jù)
? ?if (writeStream.write(chunk) === false) { // 如果沒(méi)有寫(xiě)完，暫停讀取流
? ? ? ?readStream.pause();
? ?}
});

writeStream.on('drain', function() { // 寫(xiě)完后，繼續(xù)讀取
? ?readStream.resume();
});

readStream.on('end', function() { // 當(dāng)沒(méi)有數(shù)據(jù)時(shí)，關(guān)閉數(shù)據(jù)流
? ?writeStream.end();
});