express使用中间件

基本介绍

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

 app.use(function(req,res,next) {
     console.log('first middle ware');
     next();
    console.log('first middle ware end');
 });

 app.use(function(req,res,next) {
     console.log('second middle ware');
     next(); // 必须加上 不然不会传递给下一个中间件
 });

 app.get('/',function(req,res,next) {
     res.send('Hello world1');
 })

app.listen(3000);
console.log('listen 3000');

 直接访问静态文件

public文件夹下面有个图片，可以通过如下链接访问

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

app.use(express.static('public'));

app.listen(3000);
console.log('listen 3000');

http://localhost:3000/a.jpg

 

中间件使用

index.js

var express = require('express');
var router = express.Router();

router.get('/',function(req,res,next) {

    res.send('Hello');
});

module.exports = router;

 

users.js

var express = require('express');
var router = express.Router();

router.get('/',function(req,res,next) {

    res.send('Users');
});

module.exports = router;

 

server.js

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

var indexRouter = require('./routers/index');
var usersRouter = require('./routers/users');
app.use('/',indexRouter);
app.use('/users',usersRouter);

app.listen(3000);
console.log('listen 3000');