npm i egg-init -g //安装egg
egg-init egg-example --type=simple //初始化一个egg模板例子 后面的type跟的是模板类型这里是简单的
cd egg-example//进入例子
npm i //安装依赖

'use strict';

/**
 * @param {Egg.Application} app - egg application
 */
module.exports = app => {
 const { router, controller } = app;
 router.get('/', controller.home.index);
 router.get('/custom',controller.customController.custonIndex); //自定义controller的路由
};

'use strict';

const Controller = require('egg').Controller;

class CustomController extends Controller {
  async custonIndex() { //注意这里要定义成异步方法防止请求被阻塞
    //let {id} = this.ctx.params; // 获取路由参数
    //let {name} = this.ctx.query; // 获取用户入参
    let options = {id:'5', name:2}
    
    let info = await this.ctx.service.customService.getInfo(options);//调用Service层传参
    处理，返回结果赋值
    
    this.ctx.body = {
      code: 200,
      data: info
    };//返回体
    this.ctx.status = 200;
  }
}

module.exports = CustomController;

const Service = require('egg').Service;

class CustimService extends Service {
  async getInfo(options) {
    const results = await this.app.mysql.select('test',{id:5});
    return results[0].name;
  }
}

module.exports = CustimService;

'use strict';

module.exports = appInfo => {
 const config = exports = {
   mysql:{
     // 单数据库信息配置
     client: {
       // host
       host: '44.44.44.44',
       // 端口号
       port: '3306',
       // 用户名
       user: 'mysq',
       // 密码
       password: '359359',
       // 数据库名
       database: 'mysql_db',
     },
     // 是否加载到 app 上，默认开启
     app: true,
     // 是否加载到 agent 上，默认关闭
     agent: false,
   }
 };

 // use for cookie sign key, should change to your own and keep security
 config.keys = appInfo.name + '_17792_5967';

 // add your config here
 config.middleware = [];

 return config;
};