Java - ThreadGroup toString() 方法

描述

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

声明

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

public String toString()

参数

无

返回值

此方法返回此线程组的字符串表示形式。

异常

无

获取 ThreadGroup 的字符串表示形式示例

以下示例演示了在单个 ThreadGroup 对象的情况下使用 ThreadGroup toString() 方法。我们创建了一个 ThreadGroup 对象并为其分配了一个名称。然后，我们使用前面创建的线程组对象创建了两个线程。使用 toString() 方法，我们获取了线程组对象的字符串表示形式。

package com.tutorialspoint;

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

   public void start() {
      try {     
         // create a ThreadGroup
         ThreadGroup threadGroup = new ThreadGroup("ThreadGroup");

         // create a thread
         Thread t1 = new Thread(threadGroup, this);
         System.out.println("Starting " + t1.toString() + "...");
         t1.start();
            
         // create another thread
         Thread t2 = new Thread(threadGroup, this);
         System.out.println("Starting " + t2.toString() + "...");
         t2.start();

         // returns the string representation of thread group
         System.out.println("String representation of threadGroup = " + threadGroup.toString());

         // 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 < 4;i++) {
         i++;
         try {
			Thread.sleep(50);
		} catch (InterruptedException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
      }
      System.out.println(Thread.currentThread().toString() + " finished executing.");
   }
} 

输出

让我们编译并运行上述程序，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.

获取多个 ThreadGroup 对象的字符串表示形式示例

以下示例演示了在多个 ThreadGroup 对象的情况下使用 ThreadGroup toString() 方法。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，我们使用前面创建的线程组对象创建了两个线程。使用 toString() 方法，我们打印了每个线程组对象的字符串表示形式。

package com.tutorialspoint;

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

   public void start() {
      try {     
         // create a parent ThreadGroup
         ThreadGroup pThreadGroup = new ThreadGroup("parent ThreadGroup");
		 
         // create a child ThreadGroup for parent ThreadGroup
         ThreadGroup cThreadGroup = new ThreadGroup(pThreadGroup, "child ThreadGroup");

         // create a thread
         Thread t1 = new Thread(pThreadGroup, this);
         System.out.println("Starting " + t1.toString() + "...");
         t1.start();
            
         // create another thread
         Thread t2 = new Thread(cThreadGroup, this);
         System.out.println("Starting " + t2.toString() + "...");
         t2.start();

         // returns the string representation of thread groups
         System.out.println("String representation of pThreadGroup = " + pThreadGroup.toString());
         System.out.println("String representation of cThreadGroup = " + cThreadGroup.toString());
         // 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 < 4;i++) {
         i++;
         try {
			Thread.sleep(50);
		} catch (InterruptedException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
      }
      System.out.println(Thread.currentThread().toString() + " finished executing.");
   }
} 

输出

让我们编译并运行上述程序，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.

获取子/孙 ThreadGroup 对象的字符串表示形式示例

以下示例演示了在子线程组和孙线程组对象的情况下使用 ThreadGroup toString() 方法。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，我们使用前面创建的子线程组和孙线程组对象创建了两个线程。使用 toString() 方法，我们打印了每个线程组对象的字符串表示形式。

package com.tutorialspoint;

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

   public void start() {
      try {     
         // create a parent ThreadGroup
         ThreadGroup pThreadGroup = new ThreadGroup("Parent ThreadGroup");
		 
         // create a child ThreadGroup for parent ThreadGroup
         ThreadGroup cThreadGroup = new ThreadGroup(pThreadGroup, "Child ThreadGroup");
		 
         // create a grandchild ThreadGroup for parent ThreadGroup
         ThreadGroup gThreadGroup = new ThreadGroup(cThreadGroup, "GrandChild ThreadGroup");

         // create a thread
         Thread t1 = new Thread(cThreadGroup, this);
         System.out.println("Starting " + t1.toString() + "...");
         t1.start();
            
         // create another thread
         Thread t2 = new Thread(gThreadGroup, this);
         System.out.println("Starting " + t2.toString() + "...");
         t2.start();
            
         // returns the string representation of thread groups
         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());
		 
         // 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 < 4;i++) {
         i++;
         try {
			Thread.sleep(50);
		} catch (InterruptedException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
      }
      System.out.println(Thread.currentThread().toString() + " finished executing.");
   }
} 

输出

让我们编译并运行上述程序，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.