最近工作一直很忙，没时间更新，谅解，这次准备更新一次node教程，本课堂将持续更新，每周坚持更新一到两章，希望对大家有一些小帮助吧：
一、首先什么是node？
1/Node.js 是一个基于 Chrome V8 引擎的 JavaScript 运行环境。
2/Node.js 使用了一个事件驱动、非阻塞式 I/O 的模型，使其轻量又高效。
3/Node.js 的包管理器 npm，是全球最大的开源库生态系统。
node安装不介绍了，官网直接安装即可，傻瓜式的下一步 ，在这就不耽误时间了：
二、node初体验：
1 //引入http模块 2 const http = require(‘http‘); 3 // 新建一个函数 ?作为sever的回调函数 其中req 是请求相关的内容 ?res是返回相关的内容 ?4 const func = (req,res) => { 5 ??//加上这句话防止控制台输出两边； 6 ????if (req.url !== ‘/favicon.ico‘){ 7 ??console.log(req.url); 8 ??res.write(‘<h1>11111</h1>‘); 9 ??//res.end是结束返回内容。10 ??res.end();11 ????}12 ??13 }14 // 建立sever，并且监听7001端口 15 http.createServer(func).listen(7001);16 //在终端中使用node fillname.js 即可开启。在浏览器中使用http://localhost:7001/ ??即可访问三、监听器event的简单使用方法：
1 //倒入events模块 2 const event = require(‘events‘); 3 //event的唯一模块，核心功能就是：触发事件和监听事件 4 evt = new event.EventEmitter(); 5 ?6 function eventHandler() { 7 console.log(‘监听‘); 8 } 9 //on开始监听一个指定事件，10 evt.on(‘event‘,eventHandler);11 //emit 触发制定事件12 evt.emit(‘event‘);四、event的方法：
1、once。只执行一次 不会触发多边（以及模拟异步执行）；
1 const event = require(‘events‘); 2 evt = new event.EventEmitter(); 3 function eventHandler() { 4 console.log(‘1111‘); 5 } 6 evt.once(‘event‘, eventHandler); 7 ?8 setTimeout(() => { 9 console.log(1);10 evt.emit(‘event‘);11 }, 2000);12 13 setTimeout(() => {14 console.log(0);15 evt.emit(‘event‘);16 }, 1000);2、removeListener/removeAllListeners. 移除指定的监听器
1 const event = require(‘events‘); 2 const eventEmitter = new event.EventEmitter(); 3 function func() { 4 ????console.log(‘func执行‘); 5 } 6 function func2() { 7 ????console.log(‘function2 执行‘); 8 } 9 eventEmitter.on(‘eventEmitterName‘, func);10 eventEmitter.on(‘eventEmitterName‘, func2);11 12 eventEmitter.removeListener(‘eventEmitterName‘, func);13 eventEmitter.emit(‘eventEmitterName‘);3、setMaxListeners设置监听事件的最大值(默认最大值10)+listeners。返回指定的事件的数组
?1 const event = require(‘events‘); ?2 const eventEmmiter = new event.EventEmitter(); ?3 const sever = require(‘http‘).createServer(); ?4 sever.setMaxListeners(15); ?5 sever.on(‘request‘,(req,res) =>{ ?6 ????if(req.url !== ‘/favicon.ico‘){ ?7 ????????res.writeHeader(200, { ?8 ????????????"Content-type": "text/html" ?9 ????????}); 10 ????????console.log(‘request begin‘); 11 ????????res.end(‘haha‘); 12 ????} 13 ????14 }).listen(3000); 15 sever.on(‘request‘, (req, res) => { 16 ????if (req.url !== ‘/favicon.ico‘) { 17 ????????res.writeHeader(200, { 18 ????????????"Content-type": "text/html" 19 ????????}); 20 ????????console.log(‘request begin2‘); 21 ????????res.end(‘haha1‘); 22 ????} 23 ?24 }) 25 sever.on(‘request‘, (req, res) => { 26 ????if (req.url !== ‘/favicon.ico‘) { 27 ????????res.writeHeader(200, { 28 ????????????"Content-type": "text/html" 29 ????????}); 30 ????????console.log(‘request begin3‘); 31 ????????res.end(‘haha4000‘); 32 ????} 33 ?34 }).listen(4000); 35 sever.on(‘request‘, (req, res) => { 36 ????if (req.url !== ‘/favicon.ico‘) { 37 ????????res.writeHeader(200, { 38 ????????????"Content-type": "text/html" 39 ????????}); 40 ????????console.log(‘request begin3‘); 41 ????????res.end(‘haha4000‘); 42 ????} 43 ?44 }).listen(4000); 45 sever.on(‘request‘, (req, res) => { 46 ????if (req.url !== ‘/favicon.ico‘) { 47 ????????res.writeHeader(200, { 48 ????????????"Content-type": "text/html" 49 ????????}); 50 ????????console.log(‘request begin4‘); 51 ????????res.end(‘haha1‘); 52 ????} 53 ?54 }).listen(3000); 55 sever.on(‘request‘, (req, res) => { 56 ????if (req.url !== ‘/favicon.ico‘) { 57 ????????res.writeHeader(200, { 58 ????????????"Content-type": "text/html" 59 ????????}); 60 ????????console.log(‘request begin5‘); 61 ????????res.end(‘haha1‘); 62 ????} 63 ?64 }).listen(3000); 65 sever.on(‘request‘, (req, res) => { 66 ????if (req.url !== ‘/favicon.ico‘) { 67 ????????res.writeHeader(200, { 68 ????????????"Content-type": "text/html" 69 ????????}); 70 ????????console.log(‘request begin6‘); 71 ????????res.end(‘haha1‘); 72 ????} 73 ?74 }).listen(3000); 75 sever.on(‘request‘, (req, res) => { 76 ????if (req.url !== ‘/favicon.ico‘) { 77 ????????res.writeHeader(200, { 78 ????????????"Content-type": "text/html" 79 ????????}); 80 ????????console.log(‘request begin2‘); 81 ????????res.end(‘haha1‘); 82 ????} 83 ?84 }).listen(3000); 85 sever.on(‘request‘, (req, res) => { 86 ????if (req.url !== ‘/favicon.ico‘) { 87 ????????res.writeHeader(200, { 88 ????????????"Content-type": "text/html" 89 ????????}); 90 ????????console.log(‘request begin2‘); 91 ????????res.end(‘haha1‘); 92 ????} 93 ?94 }).listen(3000); 95 sever.on(‘request‘, (req, res) => { 96 ????if (req.url !== ‘/favicon.ico‘) { 97 ????????res.writeHeader(200, { 98 ????????????"Content-type": "text/html" 99 ????????});100 ????????console.log(‘request begin2‘);101 ????????res.end(‘haha1‘);102 ????}103 104 }).listen(3000);105 sever.on(‘request1‘, (req, res) => {106 ????if (req.url !== ‘/favicon.ico‘) {107 ????????res.writeHeader(200, {108 ????????????"Content-type": "text/html"109 ????????});110 ????????console.log(‘request begin2‘);111 ????????res.end(‘haha9‘);112 ????}113 114 }).listen(3000);115 /*116 ????返回监听指定事件的数组117 */118 const arr = sever.listeners(‘request1‘)119 console.log(arr.toString());120 /*(req, res) => {121 ????if (req.url !== ‘/favicon.ico‘) {122 ????????res.writeHeader(200, {123 ????????????"Content-type": "text/html"124 ????????});125 ????????console.log(‘request begin2‘);126 ????????res.end(‘haha9‘);127 ????}128 129 } */五、本章总结代码：
1 const event =require(‘events‘); 2 const eventEmitter = new event.EventEmitter(); 3 function func(){ 4 ????console.log(‘func执行‘); 5 } 6 function func2(){ 7 ????console.log(‘function2 执行‘); 8 } 9 eventEmitter.on(‘eventEmitterName‘,func);10 eventEmitter.addListener(‘eventEmitterName‘,func2);11 let listers = require(‘events‘).EventEmitter.listenerCount(eventEmitter,‘eventEmitterName‘);12 console.log(‘当前连接数：‘+listers);13 eventEmitter.emit(‘eventEmitterName‘);14 15 eventEmitter.removeListener(‘eventEmitterName‘, func);16 17 console.log(‘---------------------------------‘);18 console.log(‘func连接取消‘);19 eventEmitter.emit(‘eventEmitterName‘);20 listers = require(‘events‘).EventEmitter.listenerCount(eventEmitter, ‘eventEmitterName‘);21 console.log(‘当前连接数：‘ + listers);22 console.log(‘-------------------------------‘);23 eventEmitter.removeListener(‘eventEmitterName‘,func2);24 listers = require(‘events‘).EventEmitter.listenerCount(eventEmitter, ‘eventEmitterName‘);25 console.log(‘当前连接数：‘ + listers);26 eventEmitter.emit(‘eventEmitterName‘);27 console.log(‘------------------------------‘);28 29 30 31 32 eventEmitter.on(‘eventEmitterName‘,func);33 34 listers = require(‘events‘).EventEmitter.listenerCount(eventEmitter, ‘eventEmitterName‘);35 console.log(‘当前连接数：‘ + listers);36 eventEmitter.emit(‘eventEmitterName‘);37 38 console.log(‘______________________‘);node基础篇一：node介绍、node http、node event 课堂（持续）
原文地址：http://www.cnblogs.com/jinzhenzong/p/8057984.html