nodejs 服务基本设置

config/mysql.json（数据库配置）

 {
        "host":"localhost",
        "port":"3306",
         "user":"root",
         "password":"root",
         "database":"ycapi"
 }

api/area.js（业务实现数据查询）

//全局Express框架

const express = require('express');
const router = express.Router();
module.exports = router;
const app = express();
//加载配置文件
const config = require('../config/mysql');
const mysql = require('mysql');
const conn = mysql.createConnection(config);
//获取数据（all方法支持post或get传参方式）
router.all('/select', (req, res) => {
// 定义SQL语句
const id = req.body.id || req.query.id;
const sqlStr = 'select * from area ' + (id ? 'where id = ?' : "");
conn.query(sqlStr, id, (err, result) => {
if (err) return result.json({code: 404, data: '获取失败'})
res.json({
        code: 0, data: result
})
});
});

api/user.js（业务实现数据查询）
//全局Express框架

const express = require('express');
const router = express.Router();
module.exports = router;
const app = express();
//加载配置文件
const config = require('../config/mysql');
const mysql = require('mysql');
const conn = mysql.createConnection(config);
//获取数据（all方法支持post或get传参方式）
router.all('/select', (req, res) => {
// 定义SQL语句
const id = req.body.id || req.query.id;
const sqlStr = 'select * from user ' + (id ? 'where id = ?' : ""); //其实也就SQL语句不同其他都一样
conn.query(sqlStr, id, (err, result) => {
if (err) return result.json({code: 404, data: '获取失败'})
res.json({
code: 0, data: result
})
});
});

main.js（入口文件，开启80端口监听，实现RESTful风格接口访问）

 const express = require('express');
const app = express();
app.listen(80, () => {
// 打印一下接口用例地址
        console.log('http://127.0.0.1/user/select')
})
const bodyParser = require('body-parser');
app.use(bodyParser.urlencoded({extended: false}))
//设置跨域访问
app.all('*', function (req, res, next) {
res.header("Access-Control-Allow-Origin", "*");
res.header("Access-Control-Allow-Headers", "X-Requested-With");
res.header("Access-Control-Allow-Methods", "PUT,POST,GET,DELETE,OPTIONS");
res.header("X-Powered-By", ' 3.2.1')
res.header("Content-Type", "application/json;charset=utf-8");
next();
});

//加入前端需要访问的接口API名称
const user = require('./api/user');
const area = require('./api/area');
app.use('/user', user);
app.use('/area', area);

node main.js启动项目，这样访问：

http://127.0.0.1/user/select

http://127.0.0.1/area/select

就可以查询到数据返回的json结果了，同时也可以用POST或者GET方式传参id