Java ThreadGroup 类

描述

Java ThreadGroup toString()方法返回此线程组的字符串表示形式。

声明

以下内容是java.lang.ThreadGroup.toString()方法的声明

public String toString()

  • 1

参数

无

返回值

此方法返回返回此线程组的字符串表示形式。

异常

无

示例 1

以下内容该示例显示了在单个 ThreadGroup 对象的情况下 ThreadGroup toString() 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。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 toString() 方法，我们获取线程组对象的字符串表示形式。

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

         //返回线程组的字符串表示
         System.out.println("String representation of threadGroup = " + threadGroup.toString());

         // 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().toString() + " finished executing.");
   }
} 

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51

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[Thread-0,5,ThreadGroup]...
Starting Thread[Thread-1,5,ThreadGroup]...
String representation of threadGroup = java.lang.ThreadGroup[name=ThreadGroup,maxpri=10]
Thread[Thread-1,5,ThreadGroup] finished executing.
Thread[Thread-0,5,ThreadGroup] finished executing.

  • 1
  • 2
  • 3
  • 4
  • 5

示例 2

以下示例显示了在多个 ThreadGroup 对象的情况下 ThreadGroup toString() 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 toString() 方法，我们打印每个线程组对象的字符串表示形式。

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

         //返回线程组的字符串表示形式
         System.out.println("String representation of pThreadGroup = " + pThreadGroup.toString());
         System.out.println("String representation of cThreadGroup = " + cThreadGroup.toString());
         // 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().toString() + " finished executing.");
   }
} 

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53

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[Thread-0,5,parent ThreadGroup]...
Starting Thread[Thread-1,5,child ThreadGroup]...
String representation of pThreadGroup = java.lang.ThreadGroup[name=parent ThreadGroup,maxpri=10]
String representation of cThreadGroup = java.lang.ThreadGroup[name=child ThreadGroup,maxpri=10]
Thread[Thread-1,5,child ThreadGroup] finished executing.
Thread[Thread-0,5,parent ThreadGroup] finished executing.

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6

示例 3

以下示例显示了 ThreadGroup toString() 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 toString() 方法，我们打印每个线程组对象的字符串表示形式。

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.toString() + "...");
         t1.start();
            
         //创建另一个线程
         Thread t2 = new Thread(gThreadGroup, this);
         System.out.println("Starting " + t2.toString() + "...");
         t2.start();
            
         //返回线程组的字符串表示形式
         System.out.println("String representation of pThreadGroup = " + pThreadGroup.toString());
         System.out.println("String representation of cThreadGroup = " + cThreadGroup.toString());
         System.out.println("String representation of gThreadGroup = " + gThreadGroup.toString());
		 
         // 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().toString() + " finished executing.");
   }
} 

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56
  • 57

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[Thread-0,5,Child ThreadGroup]...
Starting Thread[Thread-1,5,GrandChild ThreadGroup]...
String representation of pThreadGroup = java.lang.ThreadGroup[name=Parent ThreadGroup,maxpri=10]
String representation of cThreadGroup = java.lang.ThreadGroup[name=Child ThreadGroup,maxpri=10]
String representation of gThreadGroup = java.lang.ThreadGroup[name=GrandChild ThreadGroup,maxpri=10]
Thread[Thread-0,5,Child ThreadGroup] finished executing.
Thread[Thread-1,5,GrandChild ThreadGroup] finished executing.

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7