mime.json{".323":"text/h323",".3gp":"video/3gpp",".aab":"application/x-authoware-bin",".zip":"application/zip",".json":"application/json"}异步执行顺序异步方法，会等到同步处理完成后才开始执行varfs=require('fs');console.log('1')functiongetMime(){fs.readFile('mime.json',function(err,data){console.log(data.toString())console.log('2')})}console.log('3')getMime()非阻塞io直接调用，获取不到异步方法，请求数据functiongetMime(){fs.readFile('mime.json',function(err,data){returndata;})}console.log(getMime())//underfind回调函数varfs=require('fs');functiongetMime(callback){fs.readFile('mime.json',function(err,data){callback(data);})}getMime(function(result){console.log(result.toString())})node.js事件驱动最简单的事件驱动varevents=require('events');varEventEmitter=newevents.EventEmitter();事件发射器。on('to_mime',function(data){console.log(data);//数据发送到mime})EventEmitter.emit('to_mime','datasenttomime')事件驱动中有事件驱动varevents=require('events');varEventEmitter=newevents.EventEmitter();EventEmitter.on('to_mime',function(data){console.log(data);})EventEmitter.on('to_parent',function(data){console.log(data);EventEmitter.emit('to_mime','datasenttomime')})setTimeout(function(){console.log('Startbroadcasting...');EventEmitter.emit('to_parent','sentdata')},1000)获取mime.json中的数据varfs=require('fs');varevents=require('events');varEventEmiter=newevents。EventEmitter();functiongetMime(){fs.readFile('mime.json',function(err,data){EventEmiter.emit('data',data)})}getMime()EventEmiter.on('data',function(mime){console.log(mime.toString())})
