Runnable和Callable接口

1. 两者区别

Runnable

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

Callable

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

从源码中可以看到，Runnable 接口不会返回结果和抛出检查异常，但是 Callable 接口可以。

2. 两者转换

java.util.concurrent中的工具类 Executors 可以实现 Runnable 对象和 Callable 对象之间的相互转换。

class MyRunable implements Runnable {
    @Override
    public void run() {
        System.out.println(Thread.currentThread().getName() + "在运行");
    }
}

public class Test {

    public static void main(String[] args) {
        Runnable myRunnable = new MyRunable();
        
        Callable<String> myCallable = Executors.callable(myRunnable, "hahahaha");

        FutureTask task=new FutureTask(myCallable);
        Thread thread = new Thread(task);
        thread.start();
        try {
            System.out.println(task.get());
        } catch (InterruptedException e) {
            e.printStackTrace();
        } catch (ExecutionException e) {
            e.printStackTrace();
        }
    }
}

Thread-0在运行
hahahaha