1、先定义一个异步工作接口
public interface Worker { String action(Object object); }
2、再定义一个回调监听器，将Worker的执行结果 放到result的参数里
public interface Listener { void result(Object result); }
3、再定义包装器，将Worker和Listener包装一下
public class Wrapper { private Object param; private Worker worker; private Listener listener; public Object getParam() { return param; } public void setParam(Object param) { this.param = param; } public Worker getWorker() { return worker; } public void setWorker(Worker worker) { this.worker = worker; } public Listener getListener() { return listener; } public void addListener(Listener listener) { this.listener = listener; } }
4、测试回调
public class CallBackTest { public static void main(String[] args) { CallBackTest callBackTest = new CallBackTest(); Worker worker = callBackTest.newWorker(); Wrapper wrapper = new Wrapper(); wrapper.setWorker(worker); wrapper.setParam("I am a Param"); callBackTest.doWork(wrapper).addListener(new Listener() { @Override public void result(Object result) { // 耗时线程执行完毕后，回调这个方法 System.out.println(Thread.currentThread().getName()); // Thread-0 System.out.println(result); // I am a Param action result } }); System.out.println(Thread.currentThread().getName()); // main } private Wrapper doWork(Wrapper wrapper) { new Thread(() -> { Worker worker = wrapper.getWorker(); String result = worker.action(wrapper.getParam()); wrapper.getListener().result(result); }).start(); return wrapper; } private Worker newWorker() { return new Worker() { @Override public String action(Object object) { // 这里object就是param参数 try { Thread.sleep(5000); } catch (InterruptedException e) { e.printStackTrace(); } return object + " action result"; } }; } }
5、测试回调带超时
import java.util.concurrent.CompletableFuture; import java.util.concurrent.ExecutionException; import java.util.concurrent.TimeUnit; import java.util.concurrent.TimeoutException; public class CallBackTimeOutTest { public static void main(String[] args) { CallBackTimeOutTest callBackTimeOutTest = new CallBackTimeOutTest(); Worker worker = callBackTimeOutTest.newWorker(); Wrapper wrapper = new Wrapper(); wrapper.setWorker(worker); wrapper.setParam("I am Param"); //添加结果回调器 wrapper.addListener(new Listener() { @Override public void result(Object result) { System.out.println(result); // time out exception } }); CompletableFuture future = CompletableFuture.supplyAsync(() -> callBackTimeOutTest.doWork(wrapper)); try { future.get(800, TimeUnit.MILLISECONDS); // 超过800ms就算超时 } catch (InterruptedException | TimeoutException | ExecutionException e) { //超时了 wrapper.getListener().result("time out exception"); } System.out.println(Thread.currentThread().getName()); // main } private Wrapper doWork(Wrapper wrapper) { Worker worker = wrapper.getWorker(); String result = worker.action(wrapper.getParam()); wrapper.getListener().result(result); return wrapper; } private Worker newWorker() { return new Worker() { @Override public String action(Object object) { try { Thread.sleep(1000); } catch (InterruptedException e) { e.printStackTrace(); } return object + " action result"; } }; } }
