线程池的submit方法

ThreadPoolExetor#submit(Callable<T> task)   有返回值

ThreadPoolExetor#submit(Runnable task, T result)   有返回值，返回值是通过result间接获取的

ThreadPoolExetor#submit(Runnable runnable)    没有返回值，获取的nulll

public class Sumit1 {

    public static void main(String[] args) throws InterruptedException, ExecutionException {
        Callable<String> callable = new Callable<String>() {
            public String call() throws Exception {
                System.out.println("This is ThreadPoolExetor#submit(Callable<T> task) method.");
                return "result";
            }
        };

        ExecutorService executor = Executors.newSingleThreadExecutor();
        Future<String> future = executor.submit(callable);
        System.out.println(future.get());

    }
}

public class Submit2 {

    public static void main(String[] args) throws InterruptedException, ExecutionException {
        ExecutorService executor = Executors.newSingleThreadExecutor();
        Data data = new Data();
        System.out.println("before:" + data.hashCode());
        Future<Data> future = executor.submit(new Task(data), data);
        System.out.println("after:" + future.get().hashCode());
        System.out.println(future.get().getName());

    }

}

class Data {
    String name;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

class Task implements Runnable {
    Data data;

    public Task(Data data) {
        this.data = data;
    }

    public void run() {
        System.out.println("This is ThreadPoolExetor#submit(Runnable task, T result) method.");
        data.setName("kevin");
    }
}

public class Submit3 {

    public static void main(String[] args) throws InterruptedException, ExecutionException {
        Runnable runnable = new Runnable() {
            public void run() {
                System.out.println("This is ThreadPoolExetor#submit(Runnable runnable) method.");
            }
        };

        ExecutorService executor = Executors.newSingleThreadExecutor();
        Future<?> future = executor.submit(runnable);
        System.out.println(future.get());

    }
}