Express 应用级中间件 获取请求参数

Express 应用级中间件 获取请求参数

应用程序中间件

• '/路径名/:参数名'
  
• 访问 localhost:port/路径名/参数值
• 提取参数：req.params {参数名:参数值}

const express = require('express');
const app = express();

//获取单个get请求参数
//http://localhost:3000/1
app.get('/:bookid',(req,res)=>{
    console.log(req.params);//{ bookid: ':1' }
    res.send(req.params);
});

// http://localhost:3000/id1
app.get('/id:bookid',(req,res)=>{
    console.log(req.params);//{ bookid: '1' }
    res.send(req.params);
});

// http://localhost:3000/id/1
app.get('/id/:bookid',(req,res)=>{
    console.log(req.params);//{ bookid: '1' }
    res.send(req.params);
    next();
});

//提取单个参数
app.use('/user/:id',(req,res)=>{
    console.log('method:',req.method);
    res.send(req.params);
});

//提取多个参数
// http://localhost:3000/user/1/books/2
app.use('/user/:id/books/:booksid', (req, res) => {
    console.log(req.params);
    res.send(req.params);
    // {
    //     "id": "1",
    //     "booksid": "2"
    // }
});

//http://localhost:3000/user/1/books/10/three/3
app.use("*",(req,res)=>{
    res.send(req.params);//{"0": "/user/1/books/10/three/3"}
}) 


app.listen(3000, () => console.log("server run at 3000..."));