What are the ways to pass threadpoolexecutor to CompletableFuture?

Question

I have been working on Java CompletableFuture lately and found , we should always use customized Threadpool. With it, I found two ways of passing threadpool to existing code. Like below

This is my ThreadPool in configuration file

@Override
@Bean(name = "commonThreadPool")
public Executor getAsyncExecutor() {
  return new ThreadPoolTaskExecutor();
}

1. Passing existingThreadPool in argument.

 @Autowired
 @Qualifier("commonThreadPool") 
 TaskExecutor existingThreadPool;       
 CompletableFuture.runAsync(() -> executeTask(),existingThreadPool);

2. Using async like below

@Async("commonThreadPool")
public void executeTask() {
// Execute Some Task
}

is there any third way where I can write CompletableFuture Handler or Override its existing behaviour at single place where I can pass custom Threadpool. And after that wherever I use below code, it should pick my existing ThreadPool instead of forkJoin pool.

 CompletableFuture.runAsync(() -> executeTask());

Answer 1

没有为所有CompletableFuture实例替换默认执行程序的标准方法。但是从 Java 9 开始，您可以为子类定义默认执行程序。例如与

public class MyCompletableFuture<T> extends CompletableFuture<T> {
    static final Executor EXEC = r -> {
        System.out.println("executing "+r);
        new Thread(r).start();
    };

    @Override
    public Executor defaultExecutor() {
        return EXEC;
    }

    @Override
    public <U> CompletableFuture<U> newIncompleteFuture() {
        return new MyCompletableFuture<>();
    }

    public static CompletableFuture<Void> runAsync?(Runnable runnable) {
        Objects.requireNonNull(runnable);
        return supplyAsync(() -> {
            runnable.run();
            return null;
        });
    }

    public static <U> CompletableFuture<U> supplyAsync?(Supplier<U> supplier) {
        return new MyCompletableFuture<U>().completeAsync(supplier);
    }
}

您执行了所有必要步骤，为MyCompletableFuture. executor hold inEXEC仅用作示例，使用时会产生打印输出，因此当您使用该示例类时

MyCompletableFuture.supplyAsync(() -> "test")
    .thenApplyAsync(String::toUpperCase)
    .thenAcceptAsync(System.out::println);

它会打印

executing java.util.concurrent.CompletableFuture$AsyncSupply@65ab7765
executing java.util.concurrent.CompletableFuture$UniApply@119d7047
executing java.util.concurrent.CompletableFuture$UniAccept@404b9385
TEST