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Use nodejs to build a simple server
Nodejs advantages: high performance (reading and writing files) and strong data manipulation capabilities
Official website: www.nodejs.org
Verify whether the installation is successful: cmd command Enter node -v in the line. If the version number is displayed, the installation is successful.
[Common commands]
Switch drive letter d:
Enter the folder cd nodejs
Return to the previous directory cd..
Clear screen cls
Display directory dir
Copy file name, select right-click--Copy
Historical operation up arrow
Execute file node file name (in the file folder directory)
Stop the command line ctrl+c
Nodejs can use ECMAScript, read and write files, database operations, and build servers
What nodejs cannot do is: DOM, BOM
Use node to build A server:
//1、引入模块 使用的http服务协议是RFC2616 nodejs的作者已经写好了,直接引入就行 var http = require('http'); //引入文件读写模块fs var fs = require('fs'); //2、创建服务器 函数的参数req是发送给服务器的请求,res是服务器的相应 var httpObj = http.createServer(function(req,res){ //编写url 其中index.html是要服务器读取的文件 var url = req.url=='/'?'index.html':req.url; //开始文件读取,参数分别是完整的url 编码 和读取完毕执行的函数,注意前后台编码需要一致 fs.readFile('www/'+url,'utf-8',function(err,data){ //res.write服务器的相应,当成功的时候,服务器会传输一个data数据,相应结束需要end if(err){ res.write('404,您访问的页面不存在'); res.end(); }else{ res.write(data); res.end(); } }); }); //监听端口 httpObj.listen(80);
Use nodejs to write a sql statement
//和搭建服务器一样,需要先引入模块,mysqle是外生的模块(提前在node中下载),MySQL模块会告诉服务器我们需要add还是get //1、引入模块,这里多引入了一个mysql模块 var http = require('http'); var fs = require('fs'); var mysql = require('mysql'); //2、连接服务器使用createServer,同样参数也是req和res var httpObj = http.createServer(function(req,res){ var url = req.url=='/'?'index.html':req.url; console.log(url); //给前端提供一个json 写前端接口 //这里多了地址、用户名、密码和数据库 if(url.split('?')[0]=='/article'){ //console.log('我要给前端数据接口'); //1.建立连接 var db = mysql.createConnection({ //地址 host:'localhost', //用户名 user:'root', //密码 password:'', //数据库 database:'study' }); //3、编写sql语句,就是在想请求的时候告诉服务器我们需要add还是get var sql = 'SELECT * FROM user'; //3.执行sql返回结果 db.query(sql,function(err,data){ if(err){ console.log('失败'); }else{ //console.log(data[0].username); //console.log(JSON.stringify(data)); res.write(JSON.stringify(data)); res.end(); } }); }else{ //读取页面 fs.readFile('www/'+url,'utf-8',function(err,data){ if(err){ res.write('404,您访问的页面不存在'); res.end(); }else{ res.write(data); res.end(); } }); } }); //4、监听端口 httpObj.listen(3000);
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