Java? ???? ????? ? ?? ?? ???? ?????.

1 Thread ???? ???? ???? run() ???? ??????.

Thread ???? ???? ???? run() ???? ??????. ???

public class MyThread extends Thread{
    @Override
    public void run() {
        for (int i = 0 ;i < 50;i++) {
            System.out.println(Thread.currentThread().getName() + "：" + i);
        }
    }
    public static void main(String[] args) {
        for (int i = 0;i<50;i++) {
            //調(diào)用Thread類(lèi)的currentThread()方法獲取當(dāng)前線(xiàn)程
            System.out.println(Thread.currentThread().getName() + " " + i);
            if (i == 10) {
                new MyThread().start();
                new MyThread().start(); 
            }
        }
    }
}

?? ??:

...
main 48
main 49
Thread-0：0
Thread-0：1
Thread-0：2
Thread-0：3
Thread-0：4
Thread-1：0
...

???? ? ? ????.

1 ? ?? ???? ????: ??, Thread-0, Thread-1 2?? ??? ??, Thread-0 ? ???-1 ?? ?? i? ?? ????? ????(???? ?? ??? ?? ???? ?????). ??: Thread ???? ???? ?????? ??? ? ? ???? ????? ?? ?? ?? ??? ??? ???? ??? ? ??? Thread-0 ? Thread-1? ?? ?? i? ???? ?? ???.

3. ???? ??? ?????? ?? Thread-0?? Thread-1? ?? CPU? ????? ??? ????. (? ?? ??? ????? ??? ????. ??? Thread-0? Thread-1 ??? ????? ?????. ???? ??? ????? ???? ????.)

(?? ??? ??:

java ??? ????

)

2. Runnable ?????? ???? ??? ???? ?????.

Runnable ?????? ???? ?? ???? ?????. ? ???? ?? obj; ??? ????? obj? ?????. ??? ??? ???? ??, ? ??? ?? ??? ?????.

public class MyRunnable implements Runnable {
    @Override
    public void run() {
        for (int i = 0 ;i < 50 ;i++) {
            System.out.println(Thread.currentThread().getName()+"：" +i);
        }
    }

    public static void main(String[] args) {
       for (int i = 0;i < 50;i++) {
            System.out.println(Thread.currentThread().getName() + "：" +i);
            if (i == 10) {
                MyRunnable myRunnable = new MyRunnable();
                new Thread(myRunnable).start();
                new Thread(myRunnable).start();
            }
        }
        //java8 labdam方式
         new Thread(() -> {
            System.out.println(Thread.currentThread().getName());
        },"線(xiàn)程3").start();
    }
}

?? ??:

...
main：46
main：47
main：48
main：49
Thread-0：28
Thread-0：29
Thread-0：30
Thread-1：30
...

1 ??? 1? ??? 2? ???? ?? ?? i? ??????. ?, ??? ???? ???? ???? ?? ???? ??? ???? ???? ??? ??? ? ????. multiple ?? ???? ??? ?? ???? ??? ?????. ??? ? ??? ???? ??? ????? ??? ?? ? ? ????. ?? ?? ???? ??? ???? ???? ? ???? ?? ?? ??? ??? ?? ??? ???? ?????.

2 , java8? ??? ??? ? ????. ?? ???? ???? ?? ???

3. Callable ? Future ?????? ?? ??? ??

Callable ????? ?? ???? ???? call() ???? ?????. ? ???? ??? ?? ???? ???? ????? ?? ?? ????. ?? ?? Callable ?? ???? ????? ?????. FutureTask ???? ???? Callable ??? call() ??? ?? ?? ??????. FutureTask ??? ??? ???? ?????. ??? ? ???? ?????. FutureTask ??? get() ???? ???? ?? ??? ??? ?? ? ?? ?? ????.

public class MyCallable implements Callable<Integer> {
    private int i = 0;
    @Override
    public Integer call() throws Exception {
        int sum = 0;
        for (; i < 100; i++) {
            System.out.println(Thread.currentThread().getName() + " " + i);
            sum += i;
        }
        return sum;
    }

    public static void main(String[] args) throws ExecutionException, InterruptedException {
        // 創(chuàng)建MyCallable對(duì)象
        Callable<Integer> myCallable = new MyCallable();
        //使用FutureTask來(lái)包裝MyCallable對(duì)象
        FutureTask<Integer> ft = new FutureTask<Integer>(myCallable);
        for (int i = 0;i<50;i++) {
            System.out.println(Thread.currentThread().getName() + ":" + i);
            if (i == 30) {
                Thread thread = new Thread(ft);
                thread.start();
            }
        }
        System.out.println("主線(xiàn)程for循環(huán)執(zhí)行完畢..");
        Integer integer = ft.get();
        System.out.println("sum = "+ integer);
    }
}

call() ???? ?? ? ??? FutureTask ?? ?? ? <>? ??? ?????.

?? ????:

Java ?? ??

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