#!/usr/bin/env node/*添加Watcher類的構造器。它的兩個參數分別是要監控的目錄和放置修改過的文件的目錄*/function Watcher(watchDir,PRocessedDir){    this.watchDir = watchDir;    this.processedDir = processedDir;}var events = require('events'),util = require('util');/*添加繼承事件發射器行為*/util.inherits(Watcher,events.EventEmitter);var fs = require('fs'),watchDir = './watch',processedDir = './done';/*擴展EventEmitter，添加處理文件的方法*/Watcher.prototype.watch = function(){    var watcher = this;    fs.readdir(this.watchDir,function(err,files){      if(err) throw err;      for(var index in files){          watcher.emit('process',files[index]);      }    });}/*擴展EventEmitter，添加開始監控的方法*/Watcher.prototype.start = function(){    var watcher = this;    fs.watchFile(watchDir,function(){      watcher.watch();    });}/*創建監聽對象*/var watcher = new Watcher(watchDir,processedDir);/*添加監聽事件發射器*/watcher.on('process',function process(file){    var watchFile = this.watchDir + '/' + file;    var processedFile = this.processedDir + '/' + file.toLowerCase();    fs.rename(watchFile,processedFile,function(err){if(err) throw err;    });});/*啟動監聽*/watcher.start();

創建watch和done目錄。

啟動node服務：node app.js

把文件丟到watch目錄中，然后看著文件出現在done目錄中，文件名被改成小寫。