Nodejs开发WEB项目后端接口API，小试牛刀

项目结构

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

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