1、future

提前完成任务，处理其他业务，等待线程结果

public class Demo {
    public static void main(String[] args) throws Exception {
        Callable<Integer> callable = () -> {
            System.out.println("进入callable");
            TimeUnit.SECONDS.sleep(4);
            return 1;
        };
        FutureTask<Integer> task = new FutureTask<>(callable);
        Thread thread = new Thread(task);
        thread.start();
        System.out.println("处理其他业务 " );
        Integer integer = task.get();
        System.out.println("等待线程执行的结果: " + integer);
    }
}