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

异步的方法，会等到同步处理完后，才开始执行

var fs = require('fs');console.log('1')function getMime(){    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，拿不到异步方法，请求的数据

function getMime(){    fs.readFile('mime.json',function(err,data){        return data;    })}console.log(getMime())  //underfind

回调函数

var fs = require('fs');function getMime(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

var events = require('events');var EventEmitter = new events.EventEmitter();EventEmitter.on('to_mime', function (data) {    console.log(data);  //给mime发送的数据})EventEmitter.emit('to_mime', '给mime发送的数据')

事件驱动里有事件驱动

var events = require('events');var EventEmitter = new events.EventEmitter();EventEmitter.on('to_mime', function (data) {    console.log(data);})EventEmitter.on('to_parent',function(data){    console.log(data);    EventEmitter.emit('to_mime','给mime发送的数据')})setTimeout(function(){    console.log('开始广播...');    EventEmitter.emit('to_parent','发送的数据')},1000)

获取mime.json里的数据

var fs = require('fs');var events = require('events');var EventEmiter = new events.EventEmitter();function getMime(){    fs.readFile('mime.json',function(err,data){        EventEmiter.emit('data',data)    })}getMime()EventEmiter.on('data',function(mime){    console.log(mime.toString())})