node.js基础

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node.js自带的读写文件js：

var fs=require('fs');

fs.writeFileSync("corn.txt","corn is good");

console.log(fs.readFileSync("corn.txt").toString())

path:

(1)normalize:把前划线变为后划线并且前划线多加了（两条）也能自动转变为一条后划线

(2)dirname:文件的当前目录

(3)basename:文件名

(4)extname:文件拓展名

example:

var path=require('path');var websiteHome="C:/Users/zhong//Desktop//home.html"var websiteAbout="C:/Users/zhong/Desktop/about.html"console.log(path.normalize(websiteHome));console.log(path.dirname(websiteAbout));console.log(path.basename(websiteAbout));console.log(path.extname(websiteAbout));
result:
C:\Users\zhong\Desktop\home.htmlC:/Users/zhong/Desktopabout.html.html
setInterval和settimeout区别:
setInterval:重复多次
settimeout:重复一次
__dirname和__filename:
__dirname:显示文件所在目录
__filename:显示文件所在目录和名字
example:
console.log(__dirname);console.log(__filename);
result:
c:\Users\zhongjun\WebstormProjects\test\publicc:\Users\zhongjun\WebstormProjects\test\public\app.js

基础的server:
var http=require('http');function onRequest(request,response){    console.log('A user made a request'+request.url);    response.writeHead(200,{'Content-Type':'text/plain'});    response.write('Here is some data');    response.end();}http.createServer(onRequest).listen(8888);console.log("Server is now running")
简单的web server:
如果没有那个页面，那么显示:Error:404
否则，显示index.html的源代码
index.html:<!DOCTYPE html><html lang="en"><head>    <meta charset="UTF-8">    <title>hhu</title></head><body>cool</body></html>
server.js:
var http=require('http');var fs=require('fs');function send404Response(response){    response.writeHead(404,{"Content-Type":"text/plain"})    response.write('Error:404');    response.end();}function onRequest(request,response){   if(request.method=='GET' && request.url=='/'){    response.writeHead(200,{'Content-Type':'text/plain'});    fs.createReadStream('./index.html').pipe(response);    }    else{    send404Response(response);    }}http.createServer(onRequest).listen(8888);console.log("Server is now running")
安装connect:
在terminal栏中输入npm install connect
server使用function():
var connect=require('connect');var http=require('http');var app=connect();function profile(request,response){    console.log('request for profile')}app.use('/profile',profile);http.createServer(app).listen(8888);console.log('Server is running');


json：
videodata.json:{  "categoryName": "Appetizers & Sides",  "categories": [    {      "categoryID": "294",      "parentID": "304",      "subjectID": "7",      "categoryName": "Apps and Side Dishes (Laura)",      "categoryDescription": "Learn to make amazing appetizers and side dishes with Laura in the Kitchen.",      "videosCount": "101",      "forumCategoryID": "163"    },    {      "categoryID": "285",      "parentID": "304",      "subjectID": "7",      "categoryName": "Side Dishes",      "categoryDescription": "Side dish recipes for salads, vegetables, sauces with Hilah cooking.",      "videosCount": "38",      "forumCategoryID": "163"    },    {      "categoryID": "337",      "parentID": "304",      "subjectID": "7",      "categoryName": "Side Dishes (bt)",      "categoryDescription": "Side dish recipes with Byron Talbott.",      "videosCount": "5",      "forumCategoryID": "163"    },    {      "categoryID": "301",      "parentID": "304",      "subjectID": "7",      "categoryName": "Side Dishes for Barbecue",      "categoryDescription": "Barbecue side dish recipes done on the grill by the BBQ Pit Boys!",      "videosCount": "43",      "forumCategoryID": "163"    },    {      "categoryID": "297",      "parentID": "304",      "subjectID": "7",      "categoryName": "Soups and Salads (Laura)",      "categoryDescription": "Looking for the perfect recipe to start your meal? Or are you looking to eat something on the lighter side? These are sure to have you covered!",      "videosCount": "70",      "forumCategoryID": "163"    }  ]}

app.js:全局引用

app.locals.videodata=require('./videodata.json');

index.ejs:显示

<!DOCTYPE html><html>  <head>    <title>home</title>    <link rel='stylesheet' href='/stylesheets/style.css' />  </head>  <body>    <h3><%= videodata.categoryName %> </h3>    <ul>      <% videodata.categories.forEach(function(item){%>        <li><%= item.categoryName%> </li>      <%})%>    </ul>  </body></html>

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