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线程的实现方式
- 继承Thread类：void run()方法没有返回值，无法抛异常
- 实现Runnable接口：void run()方法没有返回值，无法抛异常
- 实现Callable接口：V call() throws Exception 返回结果，能够抛异常
实现Callable接口
（1）创建Callable接口的实现类，并实现call()方法，该call()方法将作为线程执行体，并且有返回值。
（2）创建Callable实现类的实例，使用FutureTask类来包装Callable对象，该FutureTask对象封装了该Callable对象的call()方法的返回值。
（3）使用FutureTask对象作为Thread对象的target创建并启动新线程。
（4）调用FutureTask对象的get()方法来获得子线程执行结束后的返回值
任务
四匹马，跑一千米比赛，每匹马的速度通过1~10的随机数来产生，输出哪匹马是冠军
RunTask1.java代码：
import java.util.Random;
import java.util.concurrent.Callable;/*** 跑步任务*/public class RunTask1 implements Callable<Long> {// step/100ms 是否睡着 睡觉时间// 通过方法形参接收参数// 定义属性private int step;private boolean isSleep;private int sleepTime;public RunTask1(int step,boolean isSleep,int sleepTime){this.step=step;this.isSleep=isSleep;this.sleepTime=sleepTime;}@Overridepublic Long call() throws Exception {int distance=0;long start = System.currentTimeMillis();while(true){distance+=step;if (isSleep) {if (distance == 800) { //跑到800米try {System.out.println(Thread.currentThread().getName() + "睡" + sleepTime + "ms");Thread.sleep(sleepTime);} catch (InterruptedException e) {e.printStackTrace();}}}if(distance>=1000){break;}System.out.println(Thread.currentThread().getName() + "跑完" + distance + "米");}try {Thread.sleep(100);} catch (InterruptedException e) {e.printStackTrace();}return System.currentTimeMillis()-start;}
}
Test.java代码
import java.util.Random;
import java.util.concurrent.FutureTask;public class Test {public static void main(String[] args) throws Exception {//第一匹马的跑步任务RunTask1 horse1=new RunTask1(new Random().nextInt(10)+1,true,200);FutureTask<Long> horseResult = new FutureTask<>(horse1);Thread t1=new Thread(horseResult,"马1");//第二匹马的跑步任务RunTask1 horse2=new RunTask1(new Random().nextInt(10)+1,true,400);FutureTask<Long> horseResult1 = new FutureTask<>(horse2);Thread t2=new Thread(horseResult1,"马2");//第三匹马的跑步任务RunTask1 horse3=new RunTask1(new Random().nextInt(10)+1,true,5500);FutureTask<Long> horseResult2 = new FutureTask<>(horse3);Thread t3=new Thread(horseResult2,"马3");//第四匹马的跑步任务RunTask1 horse4=new RunTask1(new Random().nextInt(10)+1,false,0);FutureTask<Long> horseResult3 = new FutureTask<>(horse4);Thread t4=new Thread(horseResult3,"马4");t1.start();t2.start();t3.start();t4.start();//统计比赛结果，一定要等main线程执行，否则， Horse1的线程还没跑完，就输出了winner is Horse2if((horseResult.get().longValue() < horseResult1.get().longValue()) && (horseResult.get().longValue() < horseResult2.get().longValue()) && (horseResult.get().longValue() < horseResult3.get().longValue())){System.out.println("winner is "+t1.getName());}else if((horseResult1.get().longValue() < horseResult.get().longValue()) && (horseResult1.get().longValue() < horseResult2.get().longValue()) && (horseResult1.get().longValue() < horseResult3.get().longValue())){System.out.println("winner is "+t2.getName());}else if((horseResult2.get().longValue() < horseResult.get().longValue()) && (horseResult2.get().longValue() < horseResult1.get().longValue()) && (horseResult2.get().longValue() < horseResult3.get().longValue())){System.out.println("winner is "+t3.getName());}else if(horseResult3.get().longValue() < horseResult.get().longValue() && (horseResult3.get().longValue() < horseResult1.get().longValue()) && (horseResult3.get().longValue() < horseResult2.get().longValue())){System.out.println("winner is "+t4.getName());}else System.out.println("平局");}
}
控制台输出，想要结果不一样，可以通过设置哪一匹马会睡眠，从而改变结果，代码还是有不足：
