创建线程3--实现Callable接口

注意：

1.实现Runnable接口创建线程没有直接的返回值，但可以通过额外添加成员变量和get方法实现同样的效果。
2.如果run方法内有异常不能抛出，要在内部直接抓取。

1.实现Callable接口创建线程的简单实现：

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;


public class MyThread {
    public static void main(String[] args) throws InterruptedException, ExecutionException {
        //创建线程
        ExecutorService executorService = Executors.newFixedThreadPool(1);
        Race tortoise = new Race();
        //获取值
        Future<Integer> future = executorService.submit(tortoise);
        int sum = future.get();
        System.out.println(sum);

        
        executorService.shutdown();
    }
}
class Race implements Callable<Integer>{
    @Override
    public Integer call() throws Exception {
        // TODO Auto-generated method stub
        return 1000;
    }
}

2.实现Callable接口创建线程的复杂实现：

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;


public class MyThread {
    public static void main(String[] args) throws InterruptedException, ExecutionException {
        //创建线程
        ExecutorService executorService = Executors.newFixedThreadPool(2);
        Race tortoise = new Race("乌龟", 1000);
        Race rabbit = new Race("兔子", 500);
        //获取值
        Future<Integer> tortoiseFuture = executorService.submit(tortoise);
        Future<Integer> rabbitFuture = executorService.submit(rabbit);

        
        Thread.sleep(2000);//2秒
        tortoise.setFlag(false);//停止线程体循环
        rabbit.setFlag(false);

        
        int tortoiseSum = tortoiseFuture.get();
        int rabbitSum = rabbitFuture.get();
        System.out.println("乌龟跑了：" + tortoiseSum + "步。");
        System.out.println("兔子跑了：" + rabbitSum + "步。");

        
        executorService.shutdown();
    }
}
class Race implements Callable<Integer>{
    private String name;//名称
    private long time;//延迟时间
    private boolean flag = true;//是否继续走
    private int step;//步

    
    public Race(String name, long time) {
        this.name = name;
        this.time = time;
    }

    
    public void setFlag(boolean flag) {
        this.flag = flag;
    }


    @Override
    public Integer call() throws Exception {
        // TODO Auto-generated method stub
        while(flag) {
            Thread.sleep(time);//延迟
            step++;
        }
        return step;
    }
}