Nodejs express 连接Mysql

【npm项目地址】：https://www.npmjs.com/package/mysql

建立连接

const mysql = require("mysql");
const MysqlConfig = {
    host: "localhost",
    port: "3306",
    user: "xujiayi",
    password: "123456",
    database: "clipboard"
}

let conn = mysql.createConnection(MysqlConfig);

conn.connect(function (err) {
    if (err) {
        console.log("error connecting:" + err.stack);
    } else {
        console.log("Mysql connected as id " + conn.threadId);
    }
})
js

查询

conn.query(sql, params, (err, result, fields) => {
    if (err) console.log(err)
    else console.log(result, fields)
})
js

封装导出

//封装一下
export const QueryDB = (sql, params = []) => {
    return new Promise((resolve, reject) => {
        conn.query(sql, params, (err, result, fields) => {
            if (err) reject(err)
            else resolve(result, fields)
        })
    })
}

js

查询

const express = require("express");
const app = express();
import {QueryDB} from "./MysqlService";

app.use(express.json())

app.get("/search",(req,res,next)=>{

    QueryDB("SELECT * FROM `tb_clipboard`").then(result=>{
        console.log(result)
        res.status(200).send(result)
    }).catch(error=>{
        console.log(error)
        res.status(500).send("查询出错")
    })

})

module.exports={
    path:"api"
    handler:app
}
js

优化 —— 建立连接池

const mysql = require("mysql");

const MysqlPoolConfig = {
    host: "localhost",
    connectionLimit: 20,
    port: 3306,
    user: "xujiayi",
    password: "123456",
    database: "clipboard"
}

const pool = mysql.createPool(MysqlPoolConfig);

pool.getConnection((err, conn) => {
    if (err) console.log(err)
    conn.query("SELECT * FROM `tb_clipboard`", [], (err, result, fields) => {
        if (err) console.log(err)
        else console.log(result, fields)
    })
    conn.release();
})

export const QueryDB = (sql, params = []) => {
    return new Promise((resolve, reject) => {
        pool.getConnection((err, conn) => {
            if (err) reject(err)
            conn.query(sql, params, (err, result, fields) => {
                if (err) reject(err)
                else resolve(result, fields)
            })
            conn.release();
        })
    })
}
js

查询和前面的方法一致