node+express解决前端跨域问题

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

//解决跨域
app.all('*',function (req, res, next) {
  res.header('Access-Control-Allow-Origin', '*');
  res.header('Access-Control-Allow-Headers', 'Content-Type, Content-Length, Authorization, Accept, X-Requested-With');
  res.header('Access-Control-Allow-Methods', 'PUT, POST, GET, DELETE, OPTIONS');
  if (req.method == 'OPTIONS') {
    res.send(200);
  }
  else {
    next();
  }
});
var server = app.listen(8081, function () {
  var host = server.address().address
  var port = server.address().port
  console.log("应用实例，访问地址为 http://%s:%s", host, port)
 
})