nodejs 实现文件拷贝

//异步形式读取文件function copyFile(url){ ???const extName = path.extname(url) ???const fileName = path.basename(url) ???const dirName = path.dirname(url) ???fs.readFile(url, (err, data) => { ???????fs.writeFile(`${dirName}/${fileName}_copy_1${extName}`, data , err => { ???????????if(err){ ???????????????console.log(`写入出现错误 ${err.toString()}`) ???????????}else{ ???????????????console.log(‘完成!‘) ???????????} ???????}) ???})}

//同步形式读取文件function copySync(url){ ???const extName = path.extname(url) ???const fileName = path.basename(url) ???const dirName = path.dirname(url) ???var data = fs.readFileSync(url) ???????fs.writeFileSync(`${dirName}/${fileName}_copy_1${extName}`,data) ???console.log(‘同步拷贝完成!‘)}

const fs = require(‘fs‘)const path = require(‘path‘)// 使用流拷贝function streamCopyFile(url){ ???const extName = path.extname(url) ???const fileName = path.basename(url) ???const dirName = path.dirname(url) ???let options = { ???????highWaterMark : 64 * 1024 //默认值，每个chunk的大小 ???} ???const readable = fs.createReadStream(url, options) ???const writable = fs.createWriteStream(`${dirName}/${fileName}_copy${extName}`) ???var size = 0 ???var totalSize = 0 ???const stat = fs.stat(url, (err , stats) => { ???????totalSize = stats.size ???}) ???readable.on(‘open‘, () => { ???????console.log(‘打开文件‘); ???}) ???readable.on(‘data‘, data => { ???????size = data.length + size ???????console.log(‘已完成 ‘ + parseInt((size / totalSize) * 100) + ‘%‘); ???????writable.write(data) ???????readable.pause() ???}) ???readable.on(‘end‘, () => { ???????console.log(‘读取完成‘) ???}) ???readable.on(‘error‘, err => { ???????console.log(`读取时出现错误 ${err.toString()}`) ???}) ???writable.on(‘error‘, err => { ???????console.log(`写入时出现错误 ${err.toString()}`) ???}) ???//将内存中数据全部写入文件后触发 drain 事件 ???writable.on(‘drain‘, () => { ???????readable.resume() ???}) ???writable.on(‘finish‘, () => { ???????console.error(‘写入完成‘); ???})}

//通过管道的方式function pipeCopyFile(url){ ???const extName = path.extname(url) ???const fileName = path.basename(url) ???const dirName = path.dirname(url) ???const readable = fs.createReadStream(url) ???const writable = fs.createWriteStream(`${dirName}/${fileName}_copy_2${extName}`) ???var size = 0 ???var totalSize = 0 ???const stat = fs.stat(url, (err , stats) => { ???????totalSize = stats.size ???}) ???writable.on(‘pipe‘, (src) => { ???????console.log(‘有数据正通过管道流入写入器‘) ???}) ???writable.on(‘finish‘, () => { ???????console.error(‘写入已完成‘) ???}) ???readable.pipe(writable)}