安装nodejs
创建第一个nodejs应用
步骤1：引用required模块
var http = require("http");
步骤2：创建服务器 ``` var http = require(‘http’);
http.createServer(function (request, response) {
// 发送 HTTP 头部
// HTTP 状态值: 200 : OK
// 内容类型: text/plain
response.writeHead(200, {'Content-Type': 'text/plain'});
// 发送响应数据 "Hello World"
response.end('Hello World\n');
}).listen(8888);
// 终端打印如下信息 console.log(‘Server running at http://127.0.0.1:8888/‘);
运行：<br />
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### NPM 使用
NPM是随同NodeJS一起安装的包管理工具，能解决NodeJS代码部署上的很多问题，常见的使用场景有以下几种：
- 允许用户从NPM服务器下载别人编写的第三方包到本地使用。
- 允许用户从NPM服务器下载并安装别人编写的命令行程序到本地使用。
- 允许用户将自己编写的包或命令行程序上传到NPM服务器供别人使用。
使用`npm -v`查询版本
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##### 使用npm 命令安装模块
npm安装Node.js模块语法：<br />` npm install <Module Name>`<br />以下实例，我们使用 npm 命令安装常用的 Node.js web框架模块 **express**:<br />`npm install express `<br />安装好之后，express 包就放在了工程目录下的 node_modules 目录中，因此在代码中只需要通过 **require('express')** 的方式就好，无需指定第三方包路径。<br />`var express = require('express');`
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### nodejs 连接 mongoDB 数据库
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##### 1.下载mongoDB
[mongodb-win32-x86_64-2012plus-4.2.19-signed.zip](https://www.yuque.com/attachments/yuque/0/2022/zip/2673847/1650199596938-92dcc247-2b87-4a58-9782-949f03523e98.zip?_lake_card=%7B%22src%22%3A%22https%3A%2F%2Fwww.yuque.com%2Fattachments%2Fyuque%2F0%2F2022%2Fzip%2F2673847%2F1650199596938-92dcc247-2b87-4a58-9782-949f03523e98.zip%22%2C%22name%22%3A%22mongodb-win32-x86_64-2012plus-4.2.19-signed.zip%22%2C%22size%22%3A276737742%2C%22type%22%3A%22application%2Fx-zip-compressed%22%2C%22ext%22%3A%22zip%22%2C%22source%22%3A%22%22%2C%22status%22%3A%22done%22%2C%22mode%22%3A%22title%22%2C%22download%22%3Atrue%2C%22taskId%22%3A%22u27c97e81-2933-4523-9f61-c614afbd8a0%22%2C%22taskType%22%3A%22upload%22%2C%22id%22%3A%22u0969303b%22%2C%22card%22%3A%22file%22%7D)
解压后一直下一步ok
官网下载[mongoDB](https://www.mongodb.com/try/download/community?tck=docs_server)<br /><br />先把安装包下载下来，然后就是正常安装软件的步骤：<br />双击打开，next=>
<br />打上勾，继续next=><br /><br />**选Custom**<br /><br />Browser选择安装路径，我是在E盘下新建了一个[MongoDB](https://so.csdn.net/so/search?q=MongoDB&spm=1001.2101.3001.7020)文件夹装的<br /><br />直接next=><br /><br />next=><br />Install，让他自己装去吧<br /><br />这就装好啦，弹出来的软件咱就不去管它了，反正我是没用上<br />
安装链接：[https://blog.csdn.net/crsitin_spade/article/details/121383699](https://blog.csdn.net/crsitin_spade/article/details/121383699)
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##### 2.安装可视化工具
[mongodb-compass-1.27.1-win32-x64.zip](https://www.yuque.com/attachments/yuque/0/2022/zip/2673847/1650199867389-42ed495a-d4f2-4c81-8aed-f029bb0e0ba8.zip?_lake_card=%7B%22src%22%3A%22https%3A%2F%2Fwww.yuque.com%2Fattachments%2Fyuque%2F0%2F2022%2Fzip%2F2673847%2F1650199867389-42ed495a-d4f2-4c81-8aed-f029bb0e0ba8.zip%22%2C%22name%22%3A%22mongodb-compass-1.27.1-win32-x64.zip%22%2C%22size%22%3A144370417%2C%22type%22%3A%22application%2Fx-zip-compressed%22%2C%22ext%22%3A%22zip%22%2C%22source%22%3A%22%22%2C%22status%22%3A%22done%22%2C%22mode%22%3A%22title%22%2C%22download%22%3Atrue%2C%22taskId%22%3A%22uccdef478-a285-4e99-aa00-544f74f909c%22%2C%22taskType%22%3A%22upload%22%2C%22id%22%3A%22u6bbad47d%22%2C%22card%22%3A%22file%22%7D)<br />展示界面<br />
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##### 3.测试连接数据库
- 在当前目录初始化命令： `npm init -y`
效果：<br />
- 命令：` npm install mongoose`
- 编写一个js文件连接数据库
```javascript
//mongoose 第三方包，是nodejs 专门用于处理mongoDB的包
//01.下载包：npm install mongoose
const mongoose = require('mongoose');
//连接数据库
mongoose.connect('mongodb://localhost/mySchool').then((r)=>{
console.log('数据库连接成功');
}).catch((err)=>{
console.log('数据库连接成功',err);
})
- 控制台测试
Stream流
读取流文件
var fs = require('fs')
var data = ''
var readStream = fs.createReadStream('input.txt')
readStream.setEncoding('utf-8')
readStream.on('data', function (_d) {
data += _d
})
readStream.on('end', function () {
console.log(data)
})
console.log('读取完毕')
写出流文件
var fs = require('fs')
var data = '我是老尚，今年18'
var writeStream = fs.createWriteStream('1.txt')
writeStream.write(data, 'utf-8')
writeStream.end()
writeStream.on('finsh', function () {
console.log('写入完成')
})
模块系统
get / post 请求
get
代码：、
var http = require('http')
var util = require('util')
var url = require('url')
http
.createServer(function (request, response) {
response.writeHead(200, {
'Content-Type': 'text/plain;charset=utf-8',
})
var _param = url.parse(request.url, true).query
response.write('姓名' + _param.name)
response.write('\n')
response.write('年龄' + _param.age)
response.end()
})
.listen(5642)
console.log('5642，已经启动')
post
代码：
var http = require('http')
var util = require('util')
var url = require('url')
var querystring = require('querystring')
var _formHtml =
'<form method="post">' +
'网址名：<input name = "name"><br>' +
'网址URL：<input name="age"><br>' +
'<input type="submit"> ' +
'</form >'
http
.createServer(function (req, res) {
var body = ''
req.on('data', function (_d) {
body += _d
})
req.on('end', function () {
body = querystring.parse(body)
console.log(body)
res.writeHead(200, {
'Content-Type': 'text/html;charset=utf-8',
})
if (body.name) {
res.write('姓名:' + body.name)
res.write('<br/>')
res.write('年龄:' + _param.age)
} else {
res.write(_formHtml)
}
res.end()
})
})
.listen(5642)
console.log('5642，已经启动')
Express框架
Express框架的路由
Express框架的静态目录
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