Java ThreadGroup 类

说明

Java ThreadGroup getMaxPriority() 方法返回该线程组的最大优先级。属于该组的线程的优先级不能高于最大优先级。

声明

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

public final int getMaxPriority()

参数

无

返回值

该方法返回该线程组中线程的最大优先级

异常

无

示例 1

下面的示例展示了 ThreadGroup getMaxPriority() 方法在以下情况下的用法:单个 ThreadGroup 对象。我们创建了一个 ThreadGroup 对象并为其分配了一个名称。然后我们使用之前创建的线程组对象创建了两个线程。使用 getMaxPriority() 方法，我们获取所有线程组对象的最大优先级。

package com.yxjc123;
public class ThreadGroupDemo implements Runnable {
   public static void main(String[] args) {
      ThreadGroupDemo tg = new ThreadGroupDemo();
      tg.start();
   }
   public void start() {
      try {     
         //创建一个ThreadGroup
         ThreadGroup threadGroup = new ThreadGroup("ThreadGroup");

         //创建一个线程
         Thread t1 = new Thread(threadGroup, this);
         System.out.println("Starting " + t1.getName() + "...");
         t1.start();
            
         //创建另一个线程
         Thread t2 = new Thread(threadGroup, this);
         System.out.println("Starting " + t2.getName() + "...");
         t2.start();

         //返回线程组的最大优先级
         int i = threadGroup.getMaxPriority();
         System.out.println("Maximum priority of threadGroup =" + i);

         // 阻塞直到其他线程完成
         t1.join();
         t2.join();        
      } catch (InterruptedException ex) {
         System.out.println(ex.toString());
      }
   }

   // 实现 run()
   public void run() {
      for(int i = 0; i < 4;i++) {
         i++;
         try {
            Thread.sleep(50);
         } catch (InterruptedException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
         }
      }
      System.out.println(Thread.currentThread().getName() + " finished executing.");
   }
}

输出

让我们编译并运行上面的程序，这将产生以下结果结果 -

Starting Thread-0...
Starting Thread-1...
Maximum priority of threadGroup =10
Thread-0 finished executing.
Thread-1 finished executing.

示例 2

以下示例显示了在多个 ThreadGroup 对象的情况下 ThreadGroup getMaxPriority() 方法的用法。我们创建了一个 ThreadGroup 对象并为其分配了一个名称。接下来，我们创建了一个子 ThreadGroup 对象。然后我们使用之前创建的线程组对象创建了两个线程。使用 getMaxPriority() 方法，我们打印每个线程组对象的最大优先级。

package com.yxjc123;
public class ThreadGroupDemo implements Runnable {
   public static void main(String[] args) {
      ThreadGroupDemo tg = new ThreadGroupDemo();
      tg.start();
   }
   public void start() {
      try {     
         //创建父ThreadGroup
         ThreadGroup pThreadGroup = new ThreadGroup("parent ThreadGroup");
		 
         //为父ThreadGroup创建子ThreadGroup
         ThreadGroup cThreadGroup = new ThreadGroup(pThreadGroup, "child ThreadGroup");

         //创建一个线程
         Thread t1 = new Thread(pThreadGroup, this);
         System.out.println("Starting " + t1.getName() + "...");
         t1.start();
            
         //创建另一个线程
         Thread t2 = new Thread(cThreadGroup, this);
         System.out.println("Starting " + t2.getName() + "...");
         t2.start();

         //返回线程组的最大优先级
         int i = pThreadGroup.getMaxPriority();
         System.out.println("Maximum priority of pThreadGroup =" + i);

         i = cThreadGroup.getMaxPriority();
         System.out.println("Maximum priority of cThreadGroup =" + i);
         // 阻塞直到其他线程完成
         t1.join();
         t2.join();

      } catch (InterruptedException ex) {
         System.out.println(ex.toString());
      }
   }

   // 实现 run()
   public void run() {

      for(int i = 0; i < 4;i++) {
         i++;
         try {
            Thread.sleep(50);
         } catch (InterruptedException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
         }
      }
      System.out.println(Thread.currentThread().getName() + " finished executing.");
   }
}

输出

让我们编译并运行上面的程序，这将产生以下结果 -

Starting Thread-0...
Starting Thread-1...
Maximum priority of pThreadGroup =10
Maximum priority of cThreadGroup =10
Thread-1 finished executing.
Thread-0 finished executing.

示例 3

以下示例显示了 ThreadGroup getMaxPriority() 方法在子 ThreadGroup 和孙 ThreadGroup 对象的情况下的用法。我们创建了一个 ThreadGroup 对象并为其分配了一个名称。接下来，我们创建了一个子 ThreadGroup 对象。然后，我们使用之前创建的子线程组对象和孙线程组对象创建了两个线程。使用 getMaxPriority() 方法，我们打印每个线程组对象的最大优先级。

package com.yxjc123;
public class ThreadGroupDemo implements Runnable {
   public static void main(String[] args) {
      ThreadGroupDemo tg = new ThreadGroupDemo();
      tg.start();
   }
   public void start() {
      try {     
         //创建父ThreadGroup
         ThreadGroup pThreadGroup = new ThreadGroup("Parent ThreadGroup");
		 
         //为父ThreadGroup创建子ThreadGroup
         ThreadGroup cThreadGroup = new ThreadGroup(pThreadGroup, "Child ThreadGroup");
		 
         //为父ThreadGroup创建孙ThreadGroup
         ThreadGroup gThreadGroup = new ThreadGroup(cThreadGroup, "GrandChild ThreadGroup");

         //创建一个线程
         Thread t1 = new Thread(cThreadGroup, this);
         System.out.println("Starting " + t1.getName() + "...");
         t1.start();
            
         //创建另一个线程
         Thread t2 = new Thread(gThreadGroup, this);
         System.out.println("Starting " + t2.getName() + "...");
         t2.start();
            
         //返回线程组的最大优先级
         int i = pThreadGroup.getMaxPriority();
         System.out.println("Maximum priority of pThreadGroup =" + i);

         i = cThreadGroup.getMaxPriority();
         System.out.println("Maximum priority of cThreadGroup =" + i);

         i = gThreadGroup.getMaxPriority();
         System.out.println("Maximum priority of gThreadGroup =" + i);

         // 阻塞直到其他线程完成
         t1.join();
         t2.join();
      } catch (InterruptedException ex) {
         System.out.println(ex.toString());
      }
   }

   // 实现 run()
   public void run() {

      for(int i = 0; i < 4;i++) {
         i++;
         try {
            Thread.sleep(50);
         } catch (InterruptedException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
         }
      }
      System.out.println(Thread.currentThread().getName() + " finished executing.");
   }
}

输出

让我们编译并运行上面的程序，这将产生以下结果 -

Starting Thread-0...
Starting Thread-1...
Maximum priority of pThreadGroup =10
Maximum priority of cThreadGroup =10
Maximum priority of gThreadGroup =10
Thread-0 finished executing.
Thread-1 finished executing.