java.lang.ThreadGroup.setMaxPriority() 方法设置组的最高优先级。线程组中的线程已经具有更高的优先级不会受到影响。

声明

以下是java.lang.ThreadGroup.setMaxPriority()方法的声明

public final void setMaxPriority(int pri)

参数

• pri -- 这是线程组的新的优先级。

返回值

此方法不返回任何值。

异常

• SecurityException -- 如果当前线程无法修改此线程组。

例子

下面的例子显示java.lang.ThreadGroup.setMaxPriority()方法的使用。

package com.yiibai;

import java.lang.*;

public class ThreadGroupDemo implements Runnable
{
   public static void main(String[] args) {
      ThreadGroupDemo tg = new ThreadGroupDemo();
      tg.func();
   }

   public void func() {
      try {     
         // create a parent ThreadGroup
         ThreadGroup pGroup = new ThreadGroup("Parent ThreadGroup");
         // set maximum priority as 8 for Parent
         pGroup.setMaxPriority(Thread.MAX_PRIORITY - 2);
    
         // create a child ThreadGroup for parent ThreadGroup
         ThreadGroup cGroup = new ThreadGroup(pGroup, "Child ThreadGroup");
         // set maximum priority as 5 for child
         cGroup.setMaxPriority(Thread.NORM_PRIORITY);

         // create a thread with Priority as MAX
         Thread t1 = new Thread(pGroup, this);
         t1.setPriority(Thread.MAX_PRIORITY);
         System.out.println("Starting " + t1.getName() + "...");
         t1.start();
            
         // create another thread with Priority as MAX
         Thread t2 = new Thread(cGroup, this);
         t1.setPriority(Thread.MAX_PRIORITY);
         System.out.println("Starting " + t2.getName() + "...");
         t2.start();
            
         // display the number of active threads with actual priority
         System.out.println("Active threads in "" + pGroup.getName() 
         + "" = " + pGroup.activeCount());

         // block until the other threads finish
         t1.join();
         t2.join();
      }
      catch (InterruptedException ex) {
         System.out.println(ex.toString());
      }
   }

   // implements run()
   public void run() {

      for(int i = 0;i < 1000;i++) {
         i++;
      }
      System.out.println(Thread.currentThread().getName() +
      " [priority = " + Thread.currentThread().getPriority() +
      "] finished executing.");
   }
}

让我们来编译和运行上面的程序，这将产生以下结果：

Starting Thread-0...
Starting Thread-1...
Active threads in group "Parent ThreadGroup" = 2
Thread-0 [priority = 8] finished executing.
Thread-1 [priority = 5] finished executing.