nginx跨域

<br /><br />module.exports = function (app) {
  //设置跨域访问
  app.all('*', function(req, res, next) {
      res.header("Access-Control-Allow-Origin", "*");
      res.header("Access-Control-Allow-Headers", "X-Requested-With");
      res.header("Access-Control-Allow-Methods","PUT,POST,GET,DELETE,OPTIONS");
      res.header("X-Powered-By",' 3.2.1')
      res.header("Content-Type", "application/json;charset=utf-8");
      next();
  });

  app.get('/getdata', function(req, res) {
      // res.send({id:req.params.id, name: req.params.password});
      // res.send("hello");
      res.json("hello");
  });
}<br /><br />

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

const api = require('./api')
api(app)

app.listen(8889)
console.log("listen on port 8889");

<br />$.ajax({
        dataType: 'json',
        url: 'localhost:8889/server',
        type:'get',
        success: function(data){
            console.log(data);
        }
    });

node后台，前端nginx服务器ajax访问，出现跨域问题，使用nginx反向代理