Introduction to the core methods of the CompletableFuture interface

CompletableFuture can be seen as an upgraded version of the futuretask interface

To get the object, use these four methods:

runAsync(Runnable runnable,Executor executor) ;runAsync(Runnable runnable);supplyAsync(Supplier supplier);supplyAsync(Supplier supplier, Executor executor)

Demo:

ExecutorService executorService = Executors.newFixedThreadPool(3);/*** Construct with no return value*/CompletableFuture voidCompletableFuture = CompletableFuture.runAsync(() -> {System.out.println(Thread.currentThread().getName()+"No return value");try {TimeUnit.SECONDS.sleep(1);} catch (InterruptedException e) {throw new RuntimeException(e);}}, executorService);try {TimeUnit.SECONDS.sleep(1);} catch (InterruptedException e) {throw new RuntimeException(e);}/*** create a return value*/CompletableFuture uCompletableFuture = CompletableFuture.supplyAsync(() -> {System.out.println(Thread.currentThread().getName() + "return value");try {TimeUnit.SECONDS.sleep(1);} catch (InterruptedException e) {throw new RuntimeException(e);}return "hello supplier";}, executorService);System.out.println(voidCompletableFuture.get());System.out.println(uCompletableFuture.get());executorService.shutdown();