懂你所需,做你所想
当前位置: 仙桃云科 > 新闻资讯 > 技术指导 >

nodejs-基础与深入

发表日期:2017-08-07文章编辑:仙桃云科网络科技有限公司

01-nodejs介绍

1.什么是nodejs

1.(javascript跑在机器端,服务端)Javascript on the machine  
2.(跑在谷歌v8引擎上)A runtime for Google Chrome's V8 Javascript engine

2.nodejs的使用

1.构建工具(gulp,webpack都要依赖nodejs)Build Tools and Utilities
2.(web应用,web服务端)Web Applications / Web Services

3.nodejs擅长做什么

1.轻量级到大型应用 Lightweight Applications all the way up to very large
2.高并发性 High Concurrency
3.异步 Asyncronous Actions/Requests/non-blocking
4.实时 Realtime Communication
5.同构应用Isomorphic Applications - shared code between server and client 

02rounning-files

1.安装

app.js

'use strict';
//process.argv 接受变量
var command = process.argv[2];
var a = Number(process.argv[3]);
var b = Number(process.argv[4]);

if (command === 'add') {
  console.log(a+b);
} else if (command === 'sub'){
  console.log(a-b);
} else if (command === 'mul'){
  console.log(a*b);
}

CMD运行

node app.js add 1 2 //3
node app.js sub 1 2 //-1
node app.js mul 1 2 //2

03-commonjs-moudules

1.首先建一个math.js

exports.add = function(a, b){
  return a + b;
}

exports.sub = function(a, b){
  return a - b;
}

exports.mul = function(a, b){
  return a * b;
}

2.然后建一个app.js 引人math.js

var math = require('./math');
console.log(math);//{ add: [Function], sub: [Function], mul: [Function] }
var command = process.argv[2];
var a = Number(process.argv[3]);
var b = Number([process.argv[4]]);
var value = math[command](a, b);
console.log(value);//node app.js mul 1 2 结果为2

04-npm-moudulers

建立package.json

npm init

下载包

npm install axios
npm install lodash

下载包,并加到package里面

npm install axios -S
npm install lodash -S

axios使用介绍传送门

lodash使用介绍传送门

建app.js

var _ = require('lodash');
var axios = require('axios');

axios.get('http://rest.learncode.academy/api/myuser/friends').then((res) => {
  console.log(res.data);
  var jake = _.find(res.data, {name: "Jake"});
  console.log(jake);//{ name: 'Jake', age: '32', id: '57766a9a4a9cb90100bf16ec' }
})

05-npm script

简单介绍

scripts里面的
"start": "node app"
npm run start 相当于 node app

{
  "name": "5-npm-scripts",
  "version": "1.0.0",
  "description": "",
  "main": "app.js",
  "dependencies": {},
  "devDependencies": {
    "nodemon": "^1.9.2"
  },
  "scripts": {
    "start": "node app",
    "dev": "nodemon app",
    "test": "node test",
    "test-watch": "nodemon test"
  },
  "author": "",
  "license": "ISC"
}

更加详细的介绍,建议看阮一峰的scripts介绍

npm scripts 使用指南

nodemon

这个可以监控js变化

eg

app.js

'use strict';
var math = require('./math');
var value = math.add(5, 6);
console.log(value);

math.js

exports.add = function(a, b) {
  return a + b;
}

exports.subtract = function(a, b) {
  return a - b;
}

exports.multiply = function(a, b) {
  return a * b;
}

test.js

'use strict';

var assert = require('assert');

var math = require('./math');

assert(math.add(3, 4) === 7);
assert(math.subtract(3, 4) === -1);
assert(math.multiply(3, 4) === 12);

console.log("all tests passed!");

06-base-webserver

创建server.js

'use strict';
//http模块
var http = require('http');
//封装的方法
var handlers = require('./handlers');

//创建服务
var server = http.createServer(function(request, response) {
  //url地址
  var url = request.url;

  if(url === '/'){
    handlers.homepage(request, response);
  }else if (url === "/profile") {
      handlers.profile(request, response);
  } else {
      handlers.notFound(request, response);
  }
});
//端口3000
server.listen(3000);
console.log('start 3000');

handlers.js

'use strict';
//首页
exports.homepage = function(request, response){
  response.setHeader('Content-Type', 'text/html');
  response.end('<h1>helloworld</h1>')
}
//一个接口
exports.profile = function(request, response){
  var profile = {
    name : 'will',
    age : 35
  }
  response.setHeader('Content-Type','application/json');
  response.end(JSON.stringify(profile));
}

//404
exports.notFound = function(request, response) {
  response.statusCode = 404;
  response.setHeader("Content-Type", "text/html");
  response.end("<h1>404 Not Found!</h1>");
}

07-es6

1.下载babel-register

npm install babel-register -S

2.下载babel-preset-es2015

npm install babel-preset-es2015 --save-dev

main.js

require('babel-register');
require('./src/server');

server.js

import http from 'http';
import { homepage, notFound } from './handlers';

const server = http.createServer((request, response) =>{
  homepage(request, response);
});

server.listen(3000);
console.log('listen 3000');

handlers.js

export function homepage(request, response){
  response.setHeader("Content-Type", "text/html");
    response.end("hello world");
}

export function notFound(request, response){
  response.setHeader("Content-Type", "text/html");
    response.end("404");
}

08-express

express官网传送门

express 简单介绍

下载express

npm install express -S

简单的例子

const express = require('express');
//引入express
const app = express();
//链式结构,中间件,必须要有next才能执行下一步
app
  .use((req, res, next) => {
    var profile = {name: "will"};
    req.profile =  profile;
    next();
  })
  .get("/", (req, res) => {
    res.send(req.profile);
  })
//监听端口3000
app.listen(3000);
console.log('listen 3000');

09-routes的使用

新建一个users.js,然后app.use使用这个中间件

const users = require('./routes/users');
app.use('/users', users);

users.js

const express = require('express');
const router = express.Router();

router
  .get("/", (req, res) => {
    res.send(users);
  })
  .get("/:id", (req, res) => {
    const { id } = req.params;
    const user = users.find(user => user.id == id)

    if (user) {
        res.send(user);
    } else {
        res.status(404).send(`User ${id} does not exist`);
    }
  })
  .delete('/:id', (req, res) => {
    const { id } = req.params;
    const index = users.findIndex(user => user.id == id);

    if (index > -1){
        users.splice(index, 1);
        res.sendStatus(200);
    } else {
        res.status(404).send(`User ${id} does not exist`);
    }
  });

module.exports = router;

var users = [{
  "id": 1,
  "first_name": "Gregory",
  "last_name": "Garcia",
  "email": "ggarcia0@list-manage.com",
  "gender": "Male",
  "ip_address": "23.180.99.244"
}]

10-static静态文件

下载serve-favicon

npm install serve-favicon -S

静态文件

const staticAssets = __dirname + '/public';

ico地址

const favicon = require('serve-favicon');
const faviconPath = __dirname + '/public/favicon.ico';

使用

app
  .use(express.static(staticAssets))
  .use(favicon(faviconPath))

完整代码

const express = require('express');
const favicon = require('serve-favicon');
const app = express();
//静态文件
const staticAssets = __dirname + '/public';
//ico地址
const faviconPath = __dirname + '/public/favicon.ico';
app
  .use(express.static(staticAssets))
  .use(favicon(faviconPath))
  .get('/api/profile', (req, res) => {
    var profile = {name: 'will'};
    res.send(profile);
  });
app.listen(3000);

11-hjs模板引入

下载hjs

npm install hjs -S

express中引入

app
.set("views", __dirname + "/views")
.set('view engine', 'hjs')

渲染

var title = "still another title";
  var tweets = [ 
    "my first tweet",
    "other tweet",
    "yet another tweet",
  ];
res.render('index', {
      title: title,
      tweets: tweets,
      showTweets: true,
      //模板替換,公用的
      partials: {header: "header", tweets: "tweets"}
    })

views/header.hjs

<h1>title</h1>

views/tweets.hjs

<ul>
  {{#tweets}}
    <li>{{.}}</li>
  {{/tweets}}
</ul>

views/index.hjs

<html>
  <head>
    <link rel="stylesheet" href="/css/main.css">
  </head>
  <body>
    {{> header}}
    {{#showTweets}}
      {{> tweets}}
    {{/showTweets}}
    <script src="/js/main.js"></script>
  </body>
</html>

server.js完整代码

'use strict';
const express = require('express');
const favicon = require('serve-favicon');

const app = express();
const staticAssets = __dirname + '/public';
//const faviconPath = __dirname + '/public/favicon.ico';

app
  .set("views", __dirname + "/views")
  .set('view engine', 'hjs')
  .use(express.static(staticAssets))
  //.use(favicon(faviconPath))
  .get('/', (req, res) => {
    var title = "still another title";
    var tweets = [ 
      "my first tweet",
      "other tweet",
      "yet another tweet",
    ];
    res.render('index', {
      title: title,
      tweets: tweets,
      showTweets: true,
      //模板替換,公用的
      partials: {header: "header", tweets: "tweets"}
    })
  });
app.listen(3000);
console.log('listen 3000');

12-mysql

连接mysql数据库,终于到了这步。

mysql 下载

npm install mysql -S

knex下載 knex传送门

npm install knex -S

链接mysql

const db = knex({
  client: 'mysql',
  connection: {
    host: '127.0.0.1',
    user: 'root',
    database: 'test_node',
    password: 'youpassword'
  }
})

完整代码(这里是用RESTful)

const express = require('express');
const bodyParser = require('body-parser');
const knex = require('knex');

const db = knex({
  client: 'mysql',
  connection: {
    host: '127.0.0.1',
    user: 'root',
    database: 'test_node',
    password: 'youpassword'
  }
})

// GET /users 获取所有用户
// GET /user/:id 获取id
// POST /users 创建用户
// PUT /users/:id 更新用户
// DELETE /users/:id 删除用户
express()
  .use(bodyParser.json())
  .get('/users', (req, res, next) => {
    db('users').then((users) => {
      res.send(users);
    }, next)
  })
  .post('/users', (req, res, next) => {
    db('users')
      .insert(req.body)
      .then((userIds) =>{
        res.send(userIds)
      }, next)
  })
  .get('/users/:id', (req, res, next) => {
    const { id } = req.params;

    db('users')
      .where('id', id)
      .first()
      .then((users)=>{
        if(!users){
          return res.send(400);
        }
        res.send(users)
      }, next)
  })
  .put('/users/:id', (req, res, next) => {
    const { id } = req.params;

    db('users')
      .where('id', id)
      .update(req.body)
      .then((result) => {
        if(result === 0){
          return res.send(400)
        }
        res.send(200)
      }, next)
  })
  .delete('/users/:id', (req, res, next) => {
    const { id } = req.params;

    db('users')
      .where('id', id)
      .delete()
      .then((result) => {
        if(result === 0){
          return res.send(400)
        }
        res.send(200)
      }, next)
  })
  .listen(3000)
console.log('listen 3000');
如没特殊注明,文章均为仙桃云科网络原创,转载请注明来自>
相关新闻

Java6和Java8在Windows上共存...

最近在做一个Android的项目,一开始安装的是Java8用于项目的开发。但是在项目后期需要用到drozer用于检测项目的安全性,要搭建drozer的测试环境必须要使用Java6,否则会出...

日期:2017-08-30

OpenGL与CUDA互操作方式总结...

一、介绍 CUDA是Nvidia推出的一个通用GPU计算平台,对于提升并行任务的效率非常有帮助。本人主管的项目中采用了OpenGL做图像渲染,但是在数据处理方面比较慢,导致帧率一直...

日期:2017-08-18

nodejs-基础与深入...

01-nodejs介绍 1.什么是nodejs 1. (javascript跑在机器端,服务端)Javascript on the machine 2. (跑在谷歌v8引擎上)A runtime for Google Chrome s V8 Javascript eng...

日期:2017-08-07

InnoDB关键特性之刷新邻接页-异...

Flush neighbor page 1、工作原理 2、参数控制 AIO 1、开启异步IO 一、刷新邻接页功能 1、工作原理 当刷新一个脏页时,innodb存储引擎会检测该页所在区(extent)的所有页,...

日期:2017-07-31

Java8 Stream代码详解+BenchMark...

1、基本介绍 1、创建方式 1、Array的Stream创建 1、直接创建 // main Stream stream = Stream. of ( a , b , c );String [] strArray = new String[] { a , b , c };stream...

日期:2017-07-24

Java 数据类型在实际开发中应用...

在实际编程中,往往存在着这样的数据集,它们的数值在程序中是稳定的,而且数据集中的元素是有限的。在JDK1.5之前,人们用接口来描述这一种数据类型。 1.5以后引入枚举 一...

日期:2017-07-17