node.js数据库操作

Posted 2022-11-17 jjq-exchange

node 中使用mysql
        const http = require(‘http‘);
        const mysql = require(‘mysql‘);
        const url = require(‘url‘);
        const fs = require(‘fs‘);

        //1.连接到数据库
        let db = mysql.createConnection(
            host:‘localhost‘,
            user: ‘root‘,
            password:‘‘,
            database:‘‘
        );

        //连接池【解决并发问题】
        /*let db = mysql.createPool(
            connerctionLimit: 10,//默认就是10
            host:‘localhost‘,
            user: ‘root‘,
            password:‘‘,
            database:‘‘
        );*/


        //查询
        db.query(‘SELECT * FORM user_Table‘,(err,data)=>
            if(err)
                console.log(‘错了‘);
            else
                console.log(data);
            
        );

        //2.配合http
        http.createServer((req,res)=>
            const pathname,query  = url.parse(req.url,true);

            if(pathname === ‘/reg‘)
                //参数是否正确
                let username,password = query;
                if(!username || !password) 
                    res.write(‘用户和密码不能为空‘);
                    res.end();
                else if(username.length>32)
                    res.write(‘用户名不能大于32位‘);
                    res.end();
                else if(password.length>32)
                    res.write(‘密码不能大于32位‘);
                    res.end();
                else
                    db.query(`SELECT ID FROM user_table  WHERE username=‘$username‘`,(err,data)=>
                        if(err)
                            res.write(‘数据库有错‘);
                            res.end();
                        else if(data.length>0)
                            res.write(‘用户名已存在‘)；
                            res.end();
                        else
                            db.query(`SELECT INFO user_table (username,password) VALUES(‘$username‘,‘$password‘)`,err=>
                                if(err)
                                    res.write(‘数据库有错‘);
                                    res.end();
                                else 
                                    res.write(‘注册成功‘)；
                                    res.end();
                                
                            )
                        
                    )
                

                //检查用户名是否存在

            else if(pathname === ‘/login‘)
                
            else
                fs.readFile(‘www‘+pathname,(err,buffer)=>
                    if(err)
                        res.writeHeader(404);
                        res.write(‘no found‘);
                    else
                        res.write(buffer);
                    
                    res.end();
                )
            
        )


        3.异步模块（co-mysql）
        const co = require(‘co-mysql‘);
        let conn = mysql.createPool(
            host:‘localhost‘,
            user: ‘root‘,
            password:‘‘,
            database:‘‘
        );

        let db = co(conn);

        http.createServer(async (req,res)=>
            const pathname,query  = url.parse(req.url,true);

            if(pathname === ‘/reg‘)
                //参数是否正确
                let username,password = query;
                if(!username || !password) 
                    res.write(‘用户和密码不能为空‘);
                    res.end();
                else if(username.length>32)
                    res.write(‘用户名不能大于32位‘);
                    res.end();
                else if(password.length>32)
                    res.write(‘密码不能大于32位‘);
                    res.end();
                else
                    try
                        let data = await  db.query(`SELECT ID FROM user_table  WHERE username=‘$username‘`);
                        if(data.length>0)
                            res.write(‘用户名已存在‘)；
                        else
                            await db.query(`SELECT INFO user_table (username,password) VALUES(‘$username‘,‘$password‘)`);
                            res.write(‘注册成功‘)；
                        
                    catch(err)
                        res.write(‘数据库有错‘);
                    
                    res.end();
                

                //检查用户名是否存在

            else if(pathname === ‘/login‘)
                
            else
                fs.readFile(‘www‘+pathname,(err,buffer)=>
                    if(err)
                        res.writeHeader(404);
                        res.write(‘no found‘);
                    else
                        res.write(buffer);
                    
                    res.end();
                )
            
        )