nodejs入门学习

基础

node.js是用c++编写的一个javascript运行环境，特点：事件驱动、异步I/0。作为服务器端的javascript解释器，Node是一个轻量高效的开发平台，用户构建响应快速、高度可扩展的web应用，它使用事件驱动和非阻塞的I/O模型，非常适合开发数据密集、对实时响应要求高的分布式应用。

server.js //简单的http服务器

var http = require('http');
http.createServer(function(req, res) {
    res.writeHead(200, {'Content-Type': 'text/plain'});
    res.end('hello world
');
}).listen(8888);
console.log('server running at http://127.0.0.1');

执行：node server.js

npm

查看已安装的node包：npm list [-g]
安装node包：npm install pkgname[@ver] [-g]
移除已安装node包：npm remove|uninstall pkgname [-g]
获得帮助：npm help <command>
更新已安装包：npm update pkgname
支持express命令：npm install express-generator -g
创建全局连接：npm link express

模块

main.js

var hello = require('./hello');
hello.world();

hello.js

exports.world = function() {
    console.log('hello world');
}

main1.js

var Hello = require('./hello1');
hello = new Hello();
hello.setName('aaa');
hello.sayHello();

hello1.js

function Hello() {
    var name;
    this.setName = function(myname) {
        name = myname;
    }
    this.sayHello = function() {
        console.log('hello ' + name);
    }
}
module.exports = Hello;

事件

event.js

var EventEmitter = require('events').EventEmitter;
var event = new EventEmitter();
event.on('event1', function() {
    console.log('event1 occured.');
});
setTimeout(function() {
    event.emit('event1');
}, 1000);

event1.js

var events = require('events');
var emitter = new events.EventEmitter();
emitter.on('event1', function(arg1, arg2) {
    console.log('listener1', arg1, arg2);
});
emitter.on('event1', function(arg1, arg2) {
    console.log('listener2', arg1, arg2);
});
emitter.emit('event1', 'aaa', 123);

更多参考http://www.w3cschool.cc/nodejs/nodejs-event.html

路由

index.js

var server = require('./server');
var router = require('./router');
server.start(router.route);

server.js

var http = require('http');
var url = require('url');
function start(route) {
    function onRequest(req, res) {
        var pathname = url.parse(req.url).pathname;
        console.log('request for ' + pathname + ' received.');
        route(pathname);
        res.writeHead(200, {'Conten-Type': 'text/plain'});
        res.write('hello, world');
        res.end();
    }
    http.createServer(onRequest).listen(8888);
    console.log('server has started.');
}
exports.start = start;

router.js

function route(pathname) {
    console.log('about to route a request for ' + pathname);
}
exports.route = route;

 文件系统

fs1.js

var fs = require('fs');
fs.readFile('content.txt', function(err, data) {
    if (err) {
        console.error(err);
    } else {
        console.log(data);
    }
});

fs2.js

var fs = require('fs');
fs.readFile('content.txt', 'utf-8', function(err, data) {
    if (err) {
        console.error(err);
    } else {
        console.log(data);
    }
});

fs3.js

var fs = require('fs');
fs.open('content.txt', 'r', function(err, fd) {
    if (err) {
        console.error(err);
        return;
    }
    var buf = new Buffer(8);
    fs.read(fd, buf, 0, 8, null, function(err, bytesRead, buffer) {
        if (err) {
            console.error(err);
            return;
        }
        console.log('bytesRead: ' + bytesRead);
        console.log(buffer);
    });
});

更多参考资料

http://nodejs.org/api/all.html

https://cnodejs.org/getstart