• CompletableFuture 是jdk8进入的一个异步变成工具，可以实现多线程编程。

• 下面记录了一次，多线程处理处理一个业务的例子，并且要等待所有异步子线程执行完成后，主线程才能继续往下执行。

• supplyAsync：异步线程有返回值； runAsync：异步线程没返回值

@RestController
@RequestMapping(value = "/test")
public class ThreadController {
@Autowired
TaskService taskService;
private static final ExecutorService pool;

    static {
        ThreadFactory threadFactory = new ThreadFactoryBuilder()
                .setNameFormat("export-pool-%d") //线程名称
                .build();
        pool = new ThreadPoolExecutor(
                4,
                10,
                0L,
                TimeUnit.MILLISECONDS,
                new LinkedBlockingQueue<>(2048),
                threadFactory,
                new ThreadPoolExecutor.AbortPolicy());
    }
    
public void test() throws ExecutionException, InterruptedException {
        List<CompletableFuture<String>> futrueList = new ArrayList<>();
        for (int i = 0; i<10;i++){
            CompletableFuture<String> future = CompletableFuture.supplyAsync(() -> {
                String s = null;
                try {
                    s = taskService.testThread("");
                    Thread.sleep(2000);
                } catch (InterruptedException e) {
                    throw new RuntimeException(e);
                }
                System.out.println("标记0:"+Thread.currentThread().getName());
                return s;
            }, pool);

            futrueList.add(future);
        }
        System.out.println("标记1:"+Thread.currentThread().getName());
        CompletableFuture.allOf(futrueList.toArray(new CompletableFuture[futrueList.size()])).join(); // 等待所有子线程的任务执行完毕
        System.out.println("标记2:"+Thread.currentThread().getName());
        for (CompletableFuture<String> fu : futrueList) {
            System.out.println(fu.get());
        }
    }

运行结果：