java.lang.ThreadGroup

1. Java进程中的每一条线程都属于某一线程组
2. 如果线程实例化的时候没有指定线程组，则默认所属于父线程的线程组
3. main线程属于【java.lang.ThreadGroup[name=main,maxpri=10]】
4. 可以有两个同名的线程组，但实际上是两个不同的组

线程组可实现的一些功能

通过线程组中断一批线程

ThreadGroup中的interrupt()方法示例代码

package test;

import java.util.logging.Logger;

public class Test {
    private static final Logger log = Logger.getLogger(Test.class.getName());
    
    public static void main(String[] args) {
        log.info(Thread.currentThread().getName() + " start.");
        Test t = new Test();
        
        new Thread(new ThreadGroup("group1"), t.new SubManager(), "SubManager1").start();
        new Thread(new ThreadGroup("group2"), t.new SubManager(), "SubManager2").start();
        new Thread(t.new SubManager(), "SubManager3").start();
        
        try {
            Thread.sleep(2250);
        } catch (InterruptedException e) {
            log.severe(e.toString() + " @ " + Thread.currentThread().getName());
        }
        
        Thread.currentThread().getThreadGroup().list();
        Thread.currentThread().getThreadGroup().interrupt();
    }
    
    class SubManager implements Runnable{

        @Override
        public void run() {
            while(!Thread.currentThread().isInterrupted()) {
                log.info(Thread.currentThread().getName() + " is running.");
                
                new Thread(new SubRun(), "SubRun").start();
                
                try {
                    Thread.sleep(1000);
                } catch (InterruptedException e) {
                    log.severe(e.toString() + " @ " + Thread.currentThread().getName());
                    break;
                }
            }
        }
        
    }
    
    class SubRun implements Runnable{

        @Override
        public void run() {
            while(!Thread.currentThread().isInterrupted()) {
                log.info(Thread.currentThread().getName() + " is running.");
                try {
                    Thread.sleep(500);
                } catch (InterruptedException e) {
                    log.severe(e.toString() + " @ " + Thread.currentThread().getName());
                    break;
                }
            }
        }
        
    }
    
}

运行结果

[Wed May 08 21:24:49 CST 2019] INFO: main start.
[Wed May 08 21:24:49 CST 2019] INFO: SubManager1 is running.
[Wed May 08 21:24:49 CST 2019] INFO: SubManager3 is running.
[Wed May 08 21:24:49 CST 2019] INFO: SubManager2 is running.
[Wed May 08 21:24:49 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:49 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:49 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:49 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:49 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:49 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:50 CST 2019] INFO: SubManager1 is running.
[Wed May 08 21:24:50 CST 2019] INFO: SubManager3 is running.
[Wed May 08 21:24:50 CST 2019] INFO: SubManager2 is running.
[Wed May 08 21:24:50 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:50 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:50 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:50 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:50 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:50 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:50 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:50 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:50 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:50 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:50 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:50 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:51 CST 2019] INFO: SubManager3 is running.
[Wed May 08 21:24:51 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:51 CST 2019] INFO: SubManager1 is running.
[Wed May 08 21:24:51 CST 2019] INFO: SubManager2 is running.
[Wed May 08 21:24:51 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:51 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:51 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:51 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:51 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:51 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:51 CST 2019] INFO: SubRun is running.
[Wed May 08 21:24:51 CST 2019] INFO: SubRun is running.
java.lang.ThreadGroup[name=main,maxpri=10]
    Thread[main,5,main]
    Thread[SubManager3,5,main]
    Thread[SubRun,5,main]
    Thread[SubRun,5,main]
    Thread[SubRun,5,main]
    java.lang.ThreadGroup[name=group1,maxpri=10]
        Thread[SubManager1,5,group1]
        Thread[SubRun,5,group1]
        Thread[SubRun,5,group1]
        Thread[SubRun,5,group1]
    java.lang.ThreadGroup[name=group2,maxpri=10]
        Thread[SubManager2,5,group2]
        Thread[SubRun,5,group2]
        Thread[SubRun,5,group2]
        Thread[SubRun,5,group2]
[Wed May 08 21:24:51 CST 2019] SEVERE: java.lang.InterruptedException: sleep interrupted @ SubRun
[Wed May 08 21:24:51 CST 2019] SEVERE: java.lang.InterruptedException: sleep interrupted @ SubManager2
[Wed May 08 21:24:51 CST 2019] SEVERE: java.lang.InterruptedException: sleep interrupted @ SubRun
[Wed May 08 21:24:51 CST 2019] SEVERE: java.lang.InterruptedException: sleep interrupted @ SubRun
[Wed May 08 21:24:51 CST 2019] SEVERE: java.lang.InterruptedException: sleep interrupted @ SubRun
[Wed May 08 21:24:51 CST 2019] SEVERE: java.lang.InterruptedException: sleep interrupted @ SubRun
[Wed May 08 21:24:51 CST 2019] SEVERE: java.lang.InterruptedException: sleep interrupted @ SubRun
[Wed May 08 21:24:51 CST 2019] SEVERE: java.lang.InterruptedException: sleep interrupted @ SubRun
[Wed May 08 21:24:51 CST 2019] SEVERE: java.lang.InterruptedException: sleep interrupted @ SubManager1
[Wed May 08 21:24:51 CST 2019] SEVERE: java.lang.InterruptedException: sleep interrupted @ SubRun
[Wed May 08 21:24:51 CST 2019] SEVERE: java.lang.InterruptedException: sleep interrupted @ SubRun
[Wed May 08 21:24:51 CST 2019] SEVERE: java.lang.InterruptedException: sleep interrupted @ SubManager3