A:线程组概述
* Java中使用ThreadGroup来表示线程组,它可以对一批线程进行分类管理,Java允许程序直接对线程组进行控制。
* 默认情况下,所有的线程都属于主线程组。
* public final ThreadGroup getThreadGroup()//通过线程对象获取他所属于的组
* public final String getName()//通过线程组对象获取他组的名字
* 我们也可以给线程设置分组
* 1,ThreadGroup(String name) 创建线程组对象并给其赋值名字
* 2,创建线程对象
* 3,Thread(ThreadGroup?group, Runnable?target, String?name)
* 4,设置整组的优先级或者守护线程
B:案例演示
* 线程组的使用,默认是主线程组
-
MyRunnable mr = new MyRunnable(); Thread t1 = new Thread(mr, "张三"); Thread t2 = new Thread(mr, "李四"); //获取线程组 // 线程类里面的方法:public final ThreadGroup getThreadGroup() ThreadGroup tg1 = t1.getThreadGroup(); ThreadGroup tg2 = t2.getThreadGroup(); // 线程组里面的方法:public final String getName() String name1 = tg1.getName(); String name2 = tg2.getName(); System.out.println(name1); System.out.println(name2); // 通过结果我们知道了:线程默认情况下属于main线程组 // 通过下面的测试,你应该能够看到,默任情况下,所有的线程都属于同一个组 System.out.println(Thread.currentThread().getThreadGroup().getName());
- 自己设定线程组
-
// ThreadGroup(String name) ThreadGroup tg = new ThreadGroup("这是一个新的组"); MyRunnable mr = new MyRunnable(); // Thread(ThreadGroup group, Runnable target, String name) Thread t1 = new Thread(tg, mr, "张三"); Thread t2 = new Thread(tg, mr, "李四"); System.out.println(t1.getThreadGroup().getName()); System.out.println(t2.getThreadGroup().getName()); //通过组名称设置后台线程,表示该组的线程都是后台线程 tg.setDaemon(true); ` `
/** * @param args * ThreadGroup */ public static void main(String[] args) { //demo1(); ThreadGroup tg = new ThreadGroup("我是一个新的线程组"); //创建新的线程组 MyRunnable mr = new MyRunnable(); //创建Runnable的子类对象 Thread t1 = new Thread(tg, mr, "张三"); //将线程t1放在组中 Thread t2 = new Thread(tg, mr, "李四"); //将线程t2放在组中 System.out.println(t1.getThreadGroup().getName()); //获取组名 System.out.println(t2.getThreadGroup().getName()); tg.setDaemon(true); } public static void demo1() { MyRunnable mr = new MyRunnable(); Thread t1 = new Thread(mr, "张三"); Thread t2 = new Thread(mr, "李四"); ThreadGroup tg1 = t1.getThreadGroup(); ThreadGroup tg2 = t2.getThreadGroup(); System.out.println(tg1.getName()); //默认的是主线程 System.out.println(tg2.getName()); }
}
class MyRunnable implements Runnable {
@Override
public void run() {
for(int i = 0; i < 1000; i++) {
System.out.println(Thread.currentThread().getName() + "...." + i);
}
}