java异步回调函数返回的状态如何通知给前台？

Question

如题，有了异步函数也处理了数据，但是怎么反馈给前台呢？给点思路也好

Answer 1

WebSocketscanmakeawebpagedynamicandinteractive.HoweverinmanycasesacombinationofAjaxandHTTPstreamingand/orlongpollingcouldprovideasimpleandeffectivesolution.
Forexamplenews,mail,andsocialfeedsneedtoupdatedynamicallybutitmaybeperfectlyokaytodosoeveryfewminutes.Collaboration,games,andfinancialappsontheotherhandneedtobemuchclosertorealtime.
Latencyaloneisnotadecidingfactor.Ifthevolumeofmessagesisrelativelylow(e.g.monitoringnetworkfailures)HTTPstreamingorpollingmayprovideaneffectivesolution.Itisthecombinationoflowlatency,highfrequencyandhighvolumethatmakethebestcasefortheuseWebSocket.
看了springbootwebsocket文档说的，什么时候用轮询，什么时候用websocket说得很清楚，我还是乖乖的用轮询吧
                            

Answer 2

个人觉得最简单的是用短轮询方式：
前台发送请求A，调用后台方法，后台方法启动任务后返回结果。拿到结果后，前台定期（1s）通过请求B查询后台任务是否处理完成。