创建项目

$ express express-mysql
$ cd express-mysql
$ npm install --save-dev nodemon
$ npm install mysql

pom.xml 中添加启动项：

  ...
  "scripts": {
    "start": "node ./bin/www",
    "devstart": "nodemon ./bin/www"
  }
  ...

启动：

$ DEBUG=express-mysql:* npm run devstart

准备数据库

建表，插入测试数据：

CREATE TABLE `user` (
  `id` int(11) unsigned NOT NULL AUTO_INCREMENT,
  `name` varchar(50) DEFAULT NULL,
  `age` tinyint(4) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

INSERT INTO `user` (`id`, `name`, `age`)
VALUES
    (1,'gates',40),
    (2,'dell',33),
    (3,'liming',28);

创建配置文件 conf/db.js ：

module.exports = {
    mysql: {
        host: '127.0.0.1', 
        user: 'root',
        password: 'secret-pw',
        database:'expressdemo', // 前面建的user表位于这个数据库中
        port: 3306
    }
};

编写SQL语句，dao/userSql.js

var user = {
    insert:'INSERT INTO user(id, name, age) VALUES(0,?,?)',
    update:'update user set name=?, age=? where id=?',
    delete: 'delete from user where id=?',
    queryAll: 'select * from user'
};
 
module.exports = user;

增加

创建 dao/userDAO.js

var express = require('express');
var router = express.Router();
var mysql = require('mysql');

var config = require('../conf/db');
var $sql = require('./userSql');

var pool = mysql.createPool( config.mysql );

module.exports = {
    add: function (req, res, next) {
        pool.getConnection(function(err, connection) {
            var param = req.query || req.params;
 
            connection.query($sql.insert, [param.name, param.age], function(err, result) {
                if(err) {
                    res.send(err); 
                }else{
                    res.send('add success');
                }
 
                // 释放连接 
                connection.release();
            });
        });
    }
};

修改 routes/users.js，添加 add：

var userDao = require('../dao/userDAO');

...

router.get('/add', function(req, res, next) {
    userDao.add(req, res, next);
});

测试添加user，访问 http://localhost:3000/users/add?name=test&age=88

查询

userDAO 中添加：

    queryAll: function (req, res, next) {
        pool.getConnection(function(err, connection) {
            connection.query($sql.queryAll, function(err, result) {
                if(err) {
                    res.send(err); 
                }else{
                    res.send(result);
                }
                connection.release();
            });
        });
    }

router 中添加：

router.get('/queryall', function(req, res, next) {
    userDao.queryAll(req, res, next);
});

访问 http://localhost:3000/users/queryall

修改

userDAO 中添加：

    update: function (req, res, next) {
        pool.getConnection(function(err, connection) {
            var param = req.query || req.params;
            
            connection.query($sql.update, [param.name, param.age, +param.id], function(err, result) {
                if(err) {
                    res.send(err); 
                }else{
                    res.send('update success');
                }

                connection.release();
            });
        });
    }

router 中添加：

router.get('/update', function(req, res, next) {
    userDao.update(req, res, next);
});

访问 http://localhost:3000/users/update?id=5&name=test3&age=99

删除

userDAO 中添加：

    delete: function (req, res, next) {
        pool.getConnection(function(err, connection) {
            var id = +req.query.id;
            connection.query($sql.delete, id, function(err, result) {
                if(err) {
                    res.send(err); 
                }else{
                    res.send('delete success');
                }
                connection.release();
            });
        });
    }

router 中添加：

router.get('/delete', function(req, res, next) {
    userDao.delete(req, res, next);
});

访问 http://localhost:3000/users/delete?id=5