當(dāng)把一個(gè)事件發(fā)布到spring提供的applicationcontext中，被監(jiān)聽器偵測(cè)到，就會(huì)執(zhí)行對(duì)應(yīng)的處理方法。
事件本身
事件是一個(gè)自定義的類，需要繼承spring提供的applicationevent。
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@datapublic class myevent extends applicationevent { private string msg; public myevent(object source, string msg) { super(source); this.msg = msg; }} |
事件監(jiān)聽
基本方法是實(shí)現(xiàn)applicationlistener接口，自定義一個(gè)監(jiān)聽器，實(shí)現(xiàn)onapplicationevent()方法，然后添加到applicationcontext。
比如：
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public class mylistener implements applicationlistener<myevent> { @override public void onapplicationevent(myevent event) { system.out.print("監(jiān)聽到myevent事件"); } } ...// springboot的啟動(dòng)類中添加監(jiān)聽器 public static void main(string[] args) { springapplication application = new springapplication(myapplication.class); application.addlisteners(new mylistener()); application.run(args); } |
也可以使用注解@eventlistener（推薦）：原理就是通過掃描這個(gè)注解，創(chuàng)建監(jiān)聽器并添加到applicationcontext。
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@component@slf4jpublic class myeventhandler { @eventlistener public void handleevent(myevent event) { log.info("------------處理事件：{}", event.getmsg()); try { thread.sleep(5 * 1000l); log.info("事件1(5s)處理完成"); } catch (interruptedexception e) { e.printstacktrace(); } }} |
事件發(fā)布
可以通過上下文對(duì)象的發(fā)布方法configurableapplicationcontext::publishevent()來發(fā)布。
也可以實(shí)現(xiàn)applicationeventpublisheraware接口來發(fā)布（推薦）。
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@component@slf4jpublic class eventservice implements applicationeventpublisheraware { public applicationeventpublisher publisher; @override public void setapplicationeventpublisher(applicationeventpublisher applicationeventpublisher) { this.publisher = applicationeventpublisher; } public string doeventwork(string msg) { log.info("------------publish event:" + msg); myevent event = new myevent(this, msg); publisher.publishevent(event); return "ok"; }} |
測(cè)試代碼
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@springboottest@runwith(springrunner.class)public class eventservicetest { @autowired private eventservice service; @test public void eventtest() { string msg="java code"; service.doeventwork(msg); }} |
注意
如果2個(gè)事件之間是繼承關(guān)系，會(huì)先監(jiān)聽到子類事件，處理完再監(jiān)聽父類。
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// myevent2 extends myevent@component@slf4jpublic class myeventhandler { @eventlistener public void handleevent(myevent event) { log.info("------------處理事件：{}", event.getmsg()); try { thread.sleep(5 * 1000l); log.info("事件1(5s)處理完成"); } catch (interruptedexception e) { e.printstacktrace(); } } @eventlistener public void handleevent2(myevent2 event) { log.info("------------處理事件2：{}", event.getmsg()); try { thread.sleep(10 * 1000l); log.info("事件2(10s)處理完成"); } catch (interruptedexception e) { e.printstacktrace(); } }} |
當(dāng)我publish一個(gè)子類事件myevent2時(shí)，日志如下：
以上就是本文的全部?jī)?nèi)容，希望對(duì)大家的學(xué)習(xí)有所幫助，也希望大家多多支持服務(wù)器之家。
原文鏈接：https://www.jianshu.com/p/47ae0bbdf205
