node.js实战学习笔记02--扩展事件监听器实现文件监听

#!/usr/bin/env node/*添加Watcher类的构造器。它的两个参数分别是要监控的目录和放置修改过的文件的目录*/function Watcher(watchDir,PRocessedDir){    this.watchDir = watchDir;    this.processedDir = processedDir;}var events = require('events'),util = require('util');/*添加继承事件发射器行为*/util.inherits(Watcher,events.EventEmitter);var fs = require('fs'),watchDir = './watch',processedDir = './done';/*扩展EventEmitter，添加处理文件的方法*/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]);      }    });}/*扩展EventEmitter，添加开始监控的方法*/Watcher.prototype.start = function(){    var watcher = this;    fs.watchFile(watchDir,function(){      watcher.watch();    });}/*创建监听对象*/var watcher = new Watcher(watchDir,processedDir);/*添加监听事件发射器*/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;    });});/*启动监听*/watcher.start();

创建watch和done目录。

启动node服务：node app.js

把文件丢到watch目录中，然后看着文件出现在done目录中，文件名被改成小写。