express 设置允许跨域访问

//demo
const express = require('express');
const app = express();
//设置允许跨域访问该服务.app.all(’’, function (req, res, next) {res.header(‘Access-Control-Allow-Origin’, '’);//Access-Control-Allow-Headers ,可根据浏览器的F12查看,把对应的粘贴在这里就行res.header(‘Access-Control-Allow-Headers’, ‘Content-Type’);res.header(‘Access-Control-Allow-Methods’, ‘*’);res.header(‘Content-Type’, ‘application/json;charset=utf-8’);next();});app.get(’/hello’, function (req, res) {res.json({})});const server = app.listen(8082, function () {console.log(‘Express app server listening on port %d’, server.address().port);});