让nodejs开启服务更简单--express篇

const express = require(‘express‘)
const app = express()
 
app.post(‘/home‘, (req, res, next)=>{
    res.end(‘hello express‘)
})
 
app.listen(‘8000‘, ()=>{})

const express = require(‘express‘)
const app = express()
 
app.use(‘/‘, (req, res, next)=>{
  console.log(‘匹配到了use中间件‘)
  next()
})
 
app.post(‘/home‘, (req, res, next)=>{
    console.log(‘匹配到了post中间件‘)
    res.end(‘hello express‘)
})
 
app.listen(‘8000‘, ()=>{
  console.log(‘开启8000端口‘)
})

app.get(‘/goods/:id‘, (req, res, next)=>{
  console.log(req.url)
  console.log(req.params)
  res.end(‘params‘)
})
 
app.get(‘/login‘, (req, res, next)=>{
  console.log(req.url)
  console.log(req.query)
  res.end(‘query‘)
})

// 获取 json格式的请求参数
app.use(express.json());
//  获取 urlencoded 格式的请求参数
app.use(express.urlencoded({extended: true}));
// 在下一个匹配的post请求里通过 req.body 来获取, 有兼容性问题, 需要express4.16以上
 
app.post(‘/login‘, (req, res, next) => {
  console.log(req.body);
  res.end("login success");
});

const express = require(‘express‘)
const multer = require(‘multer‘)
const app = express()
const upload = multer()
 
// 传递非文件类型时, 使用upload.any(),传递文件类型时 upload.array("file")
app.use(‘/login‘, upload.array("file"), (req, res, next)=>{ 
   console.log(req.files)
   console.log(req.body)
   res.end(‘form-data‘) 
}) 
 
app.listen(8000, () => {
  console.log(‘开启8000端口‘)
});

app.get(‘/login‘, (req, res, next) => {
  console.log(req.query);
  // 设置响应码
  res.status(200);
    // 设置响应类型
  res.type("application/json");
  res.end(JSON.stringify({name: "kiki", age: 16}));
  
  // 以上两行可以合并成 res.json({name: "kiki", age: 16});
});

const express = require(‘express‘)
const router = express.Router()
 
router.get(‘/‘, (req, res, next)=>{
  res.json([{
    name: ‘alice‘, age: 17
  },{
    name: ‘lili‘, age: 16
  }])
})
 
router.get(‘/:id‘, (req, res, next)=>{
  res.json({ name: ‘alice‘, age: 17 })
})
 
router.post(‘/‘, (req, res, next)=>{
  res.json(‘post‘)
})
 
router.put(‘/‘, (req, res, next)=>{
  res.json(‘put‘)
})
 
router.delete(‘/‘, (req, res, next)=>{
  res.json(‘delete‘)
})
 
module.exports = router;

const express = require(‘express‘)
const userRouter = require(‘./routers/user‘)
const app = express()
 
app.use(‘/user‘, userRouter)
 
app.listen(8000, ()=>{})

const express = require(‘express‘)
const app = express()
 
const NOT_FIND = ‘NOT_FIND‘
const TIME_OUT = ‘TIME_OUT‘
 
app.get(‘/login‘, (req, res, next)=>{
  next(new Error(NOT_FIND))
})
 
app.get(‘/home‘, (req, ers, next)=>[
  next(new Error(TIME_OUT))
])
 
app.use((error, req, res, next)=>{
  console.log(‘>>>>>>>>>error‘, error)
  let code = 400;
  let message = ‘‘
  switch(error.message){
    case NOT_FIND:
      message = ‘您的信息有误‘
      break;
    case TIME_OUT:
      message = ‘已超时‘;
      break;
    default:
      break;   
  }
  res.json({
    code,
    message
  })
})
 
app.listen(8000, ()=>{})