CompletableFuture依赖链可异步运行

2024-05-21 • 问答

我如何执行完整的CompletableFuture链以使用单独的执行程序异步运行

  .thenApply(r -> {
            return validateStudents();
            })
  .thenCompose(r -> {
          return fetchAll(r);
            })
  .thenCompose(r -> {
          return processAll(r);
            })      
  .whenComplete((r,t) -> {

            });
    });

您可以使用CompletableFuture中的Async方法和默认的ForkJoinPool

所有没有显式Executor参数的异步方法都是使用ForkJoinPool.commonPool（）执行的（除非它不支持并行度至少为两个，在这种情况下，将创建一个新的线程）运行每个任务）

System.out.println(Thread.currentThread().getName());
CompletableFuture.supplyAsync(()->{
    System.out.println(Thread.currentThread().getName());
    return "supplyAsync";
}).thenApplyAsync(supply->{
    System.out.println(Thread.currentThread().getName()+"----"+supply);
    return "applyAsync";
}).thenComposeAsync(compose->{
    System.out.println(Thread.currentThread().getName()+"----"+compose);
    return CompletableFuture.completedStage("composeAsync");

});

输出：

main
ForkJoinPool.commonPool-worker-3
ForkJoinPool.commonPool-worker-3----supplyAsync
ForkJoinPool.commonPool-worker-3----applyAsync

您还可以定义自定义线程池，并且可以使用该线程池

ExecutorService pool = Executors.newFixedThreadPool(1);

    System.out.println(Thread.currentThread().getName());
CompletableFuture.supplyAsync(()->{
    System.out.println(Thread.currentThread().getName());
    return "supplyAsync";
},pool).thenApplyAsync(supply->{
    System.out.println(Thread.currentThread().getName()+"----"+supply);
    return "applyAsync";
},pool).thenComposeAsync(compose->{
    System.out.println(Thread.currentThread().getName()+"----"+compose);
    return CompletableFuture.completedStage("composeAsync");

},pool);

输出：

main
pool-1-thread-1
pool-1-thread-1----supplyAsync
pool-1-thread-1----applyAsync

CompletableFuture依赖链可异步运行

leigumeng 回答：CompletableFuture依赖链可异步运行

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