线程组

黑洞代码

发布于 2021-01-14 15:45:58

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发布于 2021-01-14 15:45:58

文章被收录于专栏：落叶飞翔的蜗牛落叶飞翔的蜗牛

线程组

概述目录

1.线程组概念

2.一级关联

3.多级关联

4.线程组自动归属

5.批量管理线程

第1节线程组的概念

把线程归属到一个线程组中，线程组中含有：

1. 线程

2. 线程组

线程组可以批量管理线程或线程组对象，有效地对线程或线程组对象进行组织。

第2节一级关联

一级关联：

父对象中有子对象，但并不创建孙对象。

创建一个线程组，将部分线程归属到该组中，以此来对零散的线程对象进行有效的管理。

public class TestThread implements Runnable {
    @Override
    public void run() {
        try {
            while (!Thread.currentThread().isInterrupted()) {
                System.out.println("ThreadName = " + Thread.currentThread().getName());
                Thread.sleep(3000);
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

public class OneLevelDemo {
    public static void main(String[] args) {
        TestThread testThread1 = new TestThread();
        TestThread testThread2 = new TestThread();
        ThreadGroup threadGroup = new ThreadGroup("新建线程组1");
        Thread t0 = new Thread(threadGroup, testThread1);
        Thread t1 = new Thread(threadGroup, testThread2);
        t0.start();
        t1.start();
        System.out.println("活动的线程数为：" + threadGroup.activeCount());
        System.out.println("线程组的名称为：" + threadGroup.getName());
    }
}

ThreadName = Thread-0
ThreadName = Thread-1
活动的线程数为：2
线程组的名称为：新建线程组1
ThreadName = Thread-1
ThreadName = Thread-0
ThreadName = Thread-0
ThreadName = Thread-1
ThreadName = Thread-1
ThreadName = Thread-0
ThreadName = Thread-0
ThreadName = Thread-1
ThreadName = Thread-1
ThreadName = Thread-0

第3节多级关联

多级关联：

父对象中有子对象，子对象中再创建子对象买也就出现了子孙的效果了。

这种写法在开发中不太常见，因为线程树如果设计得复杂反而不利于线程对象的管理，不过JDK确实提供了多级关联的线程树结构。

public class LevelsDemo {
    public static void main(String[] args) {
        ThreadGroup threadGroup1 = new ThreadGroup("线程组1");
        ThreadGroup threadGroup2
                = new ThreadGroup(threadGroup1, "线程组2");
        ThreadGroup threadGroup3
                = new ThreadGroup(threadGroup1, "线程组3");
        TestThread testThread1 = new TestThread();
        TestThread testThread2 = new TestThread();
        TestThread testThread3 = new TestThread();
        Thread t0 = new Thread(threadGroup1, testThread1);
        Thread t1 = new Thread(threadGroup2, testThread2);
        Thread t2 = new Thread(threadGroup3, testThread3);
        t0.start();
        t1.start();
        t2.start();
        System.out.println("threadGroup1线程组的名称为：" + threadGroup1.getName());
        System.out.println("threadGroup1活动的线程数为：" + threadGroup1.activeCount());
        System.out.println("threadGroup1活动的线程组数为：" + threadGroup1.activeGroupCount());
        System.out.println("threadGroup2线程组的名称为：" + threadGroup2.getName());
        System.out.println("threadGroup2活动的线程数为：" + threadGroup2.activeCount());
        System.out.println("threadGroup3线程组的名称为：" + threadGroup3.getName());
        System.out.println("threadGroup3活动的线程数为：" + threadGroup3.activeCount());
    }
}

ThreadName = Thread-0
ThreadName = Thread-2
ThreadName = Thread-1
threadGroup1线程组的名称为：线程组1
threadGroup1活动的线程数为：3
threadGroup1活动的线程组数为：2
threadGroup2线程组的名称为：线程组2
threadGroup2活动的线程数为：1
threadGroup3线程组的名称为：线程组3
threadGroup3活动的线程数为：1
ThreadName = Thread-0
ThreadName = Thread-2
ThreadName = Thread-1
ThreadName = Thread-2
ThreadName = Thread-0
ThreadName = Thread-1
ThreadName = Thread-0
ThreadName = Thread-1
ThreadName = Thread-2

第4节线程组自动归属

public class ThreadGroupAuto {
    public static void main(String[] args) {
        System.out.println("当前线程：" + Thread.currentThread().getName()
                + ", 所属线程组：" + Thread.currentThread().getThreadGroup().getName()
                + ", 线程组中有线程组数量：" + Thread.currentThread().getThreadGroup()
                .activeGroupCount());
        // 没有指定线程组，那么自动归到当前线程所属的线程组中
        ThreadGroup group = new ThreadGroup("新的组");
        System.out.println("线程组中有线程组数量："
                + Thread.currentThread().getThreadGroup().activeGroupCount());
    }
}

当前线程：main, 所属线程组：main, 线程组中有线程组数量：0
线程组中有线程组数量：1

第5节批量管理线程

public class BatchThread extends Thread {
    public BatchThread(ThreadGroup tg, String name) {
        super(tg, name);
    }

    @Override
    public void run() {
        System.out.println("ThreadName = " + Thread.currentThread().getName() +
                "开始死循环了");
        while (!this.isInterrupted()) {

        }
        System.out.println("ThreadName = " + Thread.currentThread().getName() +
                "结束了");
    }
}

public class ThreadGroupBatchDemo {
    public static void main(String[] args) throws InterruptedException {
        int batch = 5;
        ThreadGroup threadGroup = new ThreadGroup("我的线程组");
        for (int i = 0; i < batch; i++) {
            BatchThread batchThread
                    = new BatchThread(threadGroup, "线程" + i);
            batchThread.start();
        }
        Thread.sleep(10000);
        threadGroup.interrupt();
        System.out.println("调用了ThreadGroup.interrupt()方法");
    }
}

ThreadName = 线程0开始死循环了
ThreadName = 线程3开始死循环了
ThreadName = 线程4开始死循环了
ThreadName = 线程2开始死循环了
ThreadName = 线程1开始死循环了
调用了ThreadGroup.interrupt()方法
ThreadName = 线程0结束了
ThreadName = 线程1结束了
ThreadName = 线程4结束了
ThreadName = 线程3结束了
ThreadName = 线程2结束了

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原始发表：2019-07-05，如有侵权请联系 cloudcommunity@tencent.com 删除

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