package 多執行緒;

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;

import org.omg.CORBA.INTERNAL;

/**
 * @author:yb
 * @version 建立時間：2018-12-25 下午8:07:11 類說明
 */
public class Call {
    /*
     * 使用Callable創造執行緒
     
 
*/
    public static void main(String[] args) throws InterruptedException, ExecutionException {
        // 建立執行緒池
        ExecutorService service = Executors.newFixedThreadPool(2);
        Race tortoise = new Race("烏龜",1000);
        Race rabbit = new Race("兔子", 500);
        
        Future<Integer> result1 = service.submit(tortoise);
        Future
 
<Integer> result2 = service.submit(rabbit);
        
        Thread.sleep(3000);//主執行緒掛起3000ms 烏龜和兔子執行緒開始競爭cpu 即烏龜和兔子開始跑，跑的時間都是3000ms
        tortoise.setFlag(false);
        rabbit.setFlag(false);
         
        //獲取值
        int num1=result1.get();
        System.out.println("烏龜跑了"+num1+"步");
        int num2=result2.get();
        System.out.println("兔子跑了"+num2+"步");
        
        //停止服務
        service.shutdownNow();
        
    }

}

class Race implements Callable<Integer>{
    
    private String name;//名稱
    private int time;//延時
    private int step=0;//步數
    
    public Race(String name,int time) {
        super();
        this.name=name;
        this.time=time;
    }
    
    private boolean flag= true;
    public int getTime() {
        return time;
    }

    public void setTime(int time) {
        this.time = time;
    }

    public boolean isFlag() {
        return flag;
    }

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

    public int getStep() {
        return step;
    }

    public void setStep(int step) {
        this.step = step;
    }
    
    public String getName() {
        return name;
    }

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

    public Integer call() throws Exception{
    
        while(flag) {
            Thread.sleep(time);
            step++;    
        }
        return step;
    }
}

分析：

main函式也是一個執行緒，執行main函式的時候，Thread.sleep(3000);就是讓main函式執行緒掛起3000ms，所以這個3000ms是烏龜和兔子的比賽總時間，main函式執行緒掛起之後，時間片交給了烏龜和兔子執行緒讓我們去競爭佔用cpu時間片