带有返回值的任务

1. Runnable和Callable<v>对比

两者都是任务的抽象类，不同的是前者不会返回值，后者有返回值。两者源码如下：

• Runnable

@FunctionalInterface
public interface Runnable {
    public abstract void run();
}

• Callable<V>

@FunctionalInterface
public interface Callable<V> {
    V call() throws Exception;
}

2.Callable<V> 和Future<V>使用示例

ExecutorService threadPoolExecutor=Executors.newCachedThreadPool();
        
Future<Integer> future=threadPoolExecutor.submit(()->{ return 1; });
System.out.println(future.get());

threadPoolExecutor.shutdown();