Quickly master nodejs installation and getting started

One 、Nodejs

1.1、Nodejs Introduce

Official website ：http://nodejs.cn/
Node It is a let. JavaScript Development platform running on the server , It makes JavaScript Become and PHP、Python、Perl、Ruby Wait for the server-side language to be equal to the script language . Published on 2009 year 5 month , from Ryan Dahl Development , The essence is right. Chrome V8 The engine is packaged .

To put it simply Node.js It's running on the server side JavaScript. Node.js It's based on Chrome JavaScript A platform built at runtime . The underlying architecture is ：javascript. file extension ：.js

Node.js It's an event driven I/O Server side JavaScript Environmental Science , be based on Google Of V8 engine ,V8 The engine performs Javascript Very fast , Very good performance .

Download the corresponding to your system Node.js edition :
Download address ：https://nodejs.org/zh-cn/download
Help document ：https://nodejs.org/zh-cn/docs
About Nodejs：https://nodejs.org/zh-cn/about

1.2、 install

Open... After downloading The next step of mindless installation The default installation is enough

After the installation is completed, check whether the installation is successful ：

node -v

1.3、 Summary

Nodejs It's a computer language , Running in the system v8（jvm） In the engine . The file suffix is js The command to run is ：node

Two 、Nodejs Quick start

2.1、 Quick start -Hello World

1、 Create folder nodejs
2、 establish helloworld.js

 Be similar to java Medium System.out.println("")

console.log('Hello World!!!')

function ：node helloworld.js

result ：hello world!!!
3、 Open command line terminal ：Ctrl + Shift + y

The browser kernel consists of two parts ：

DOM Rendering engine ;

• java script Parser （js engine ）
• js Running in the browser kernel js Inside the engine

4、 Summary

Node.js It runs out of the browser environment JavaScript Program , be based on V8 engine

2.2、Node - Implement request response

1、 establish httpserver.js ;

//  The import module is require  Is similar to the import java.io 
const http = require('http');
// 1:  Create a httpserver service 
http.createServer(function(request,response){
    
    //  How do browsers know hello server!!! 
    response.writeHead(200,{
    'Content-type':'text/plain'}); // The meaning of this sentence is ： Tell the browser that it will 
    //  With text-plain Parse hello server  This data .
    //  Output content to the browser 
    response.end("<strong>hello server!!!</strong>");
}).listen(8888);
console.log(" The service you started is ：http://localhpst:8888 To start successfully !!");
// 2:  Monitor one port 8888
// 3:  Start the running service  node httpserver.js
// 4:  Access in browser http://localhost:8888

2、 Run the server program ;

node httpserver.js

3、 After the server starts successfully , Enter... In the browser ：http://localhost:8888/ see webserver Running successfully , And the output html page
4、 Out of Service ：ctrl + c

2.3、Node- operation MYSQL database

Reference resources ：https://www.npmjs.com/package/mysql

1： install mysql rely on

npm install mysql

2： Definition db.js To operate

//1:  Import mysql Dependency package ,  mysql A module belonging to a third party is similar to  java.sql The same thing 
var mysql = require("mysql");
// 1:  Create a mysql Of Connection object 
// 2:  Configure data connection information  
var connection =mysql.createConnection({
    
    host:"127.0.0.1",
    port:3306,
    user:"root",
    password:"mkxiaoer",
    database:"testdb"
});
// 3： Open up connections 
connection.connect();
// 4:  perform curd
connection.query("select * from user",function(error,results,fields){
    
    //  If the query fails , Direct selling 
    if(error)throw error;
    //  The query is successful 
    console.log("results = ",results);
});
// 5:  Close the connection 
connection.end();
//  The last step ： function node db.js  See the effect 

3： New database :db_test And table kss_user surface

/*
 Navicat MySQL Data Transfer
 Source Server         : localhost
 Source Server Type    : MySQL
 Source Server Version : 60011
 Source Host           : localhost:3306
 Source Schema         : testdb
 Target Server Type    : MySQL
 Target Server Version : 60011
 File Encoding         : 65001
 Date: 20/01/2021 21:38:55
*/
SET NAMES utf8mb4;
SET FOREIGN_KEY_CHECKS = 0;
-- ----------------------------
-- Table structure for user
-- ----------------------------
DROP TABLE IF EXISTS `user`;
CREATE TABLE `user`  (
  `id` int(11) NOT NULL,
  `name` varchar(255) CHARACTER SET utf8 COLLATE utf8_general_ci NULL DEFAULT NULL,
  PRIMARY KEY (`id`) USING BTREE
) ENGINE = InnoDB CHARACTER SET = utf8 COLLATE = utf8_general_ci ROW_FORMAT = Compact;
-- ----------------------------
-- Records of kss_user
-- ----------------------------
INSERT INTO `user` VALUES (1, ' Zhang San ');
INSERT INTO `user` VALUES (2, ' Li Si ');
SET FOREIGN_KEY_CHECKS = 1;

4、 function db.js

node db

If you want to develop more complex software based on Node.js The application background , Need to learn more Node.js Of Web Develop related frameworks express,art-template、koa etc.