Java - ThreadGroup uncaughtException() 方法

描述

当此线程组中的线程由于未捕获的异常而停止，并且该线程未安装特定的 Thread.UncaughtExceptionHandler 时，Java ThreadGroup uncaughtException() 方法由 Java 虚拟机调用。

声明

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

public void uncaughtException(Thread t, Throwable e)

参数

• t − 即将退出的线程。

• e − 未捕获的异常。

返回值

此方法不返回任何值。

异常

无

ThreadGroup 对象中检查未处理异常的示例

以下示例演示了在 ThreadGroup 对象的情况下使用 ThreadGroup uncaughtException() 方法。我们创建了一个新类 NewThreadGroup，它扩展了 ThreadGroup。它具有 uncaughtException() 方法的重写实现。使用 NewThreadGroup，我们正在创建一个线程组对象。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。启动线程后，我们使用 interrupt() 方法调用来中断流程。处理 InterruptedException 后，我们将抛出一个 RuntimeException，最终由 uncaughtException() 方法处理。

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 object
    	 NewThreadGroup threadGroup = new NewThreadGroup("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();
            
         try {
            Thread.sleep(500);
         } catch(InterruptedException ex) {}
         // interrupt the two threads
         t1.interrupt();
         t2.interrupt();
         // block until the other threads finish
         t1.join();
         t2.join();
      } catch (InterruptedException ex) {
         System.out.println(ex.toString());
      }
   }

   public void run() {
      try {
         System.out.print(Thread.currentThread().getName());
         System.out.println(" executing...");

         while(true) {
            Thread.sleep(500);
         }
      } catch(InterruptedException e) {
         Thread currThread = Thread.currentThread();
         System.out.print(currThread.getName());
         System.out.println(" interrupted:" + e.toString());

         // rethrow the exception
         throw new RuntimeException(e.getMessage());
      }
   } 
}

class NewThreadGroup extends ThreadGroup {

   NewThreadGroup(String n) {
      super(n);
   }

   NewThreadGroup(ThreadGroup parent, String n) {
      super(parent, n);
   }

   public void uncaughtException(Thread t, Throwable e) {
      System.out.println(t + " has unhandled exception:" + e);
   } 
} 

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]...
Thread-0 executing...
Thread-1 executing...
Thread-1Thread-0 interrupted:java.lang.InterruptedException: sleep interrupted
 interrupted:java.lang.InterruptedException: sleep interrupted
Thread[Thread-0,5,ThreadGroup] has unhandled exception:java.lang.RuntimeException: sleep interrupted
Thread[Thread-1,5,ThreadGroup] has unhandled exception:java.lang.RuntimeException: sleep interrupted

子 ThreadGroup 对象中检查未处理异常的示例

以下示例演示了在父和子 ThreadGroup 对象的情况下使用 ThreadGroup uncaughtException() 方法。我们创建了一个新类 NewThreadGroup，它扩展了 ThreadGroup。它具有 uncaughtException() 方法的重写实现。使用 NewThreadGroup，我们正在创建父、子线程组对象。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。启动线程后，我们使用 interrupt() 方法调用来中断流程。处理 InterruptedException 后，我们将抛出一个 RuntimeException，最终由 uncaughtException() 方法处理。

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
    	 NewThreadGroup pThreadGroup = new NewThreadGroup("Parent ThreadGroup");
		 
         // create a child ThreadGroup for parent ThreadGroup
    	 NewThreadGroup cThreadGroup = new NewThreadGroup(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();
            
         try {
            Thread.sleep(500);
         } catch(InterruptedException ex) {}
         // interrupt the two threads
         t1.interrupt();
         t2.interrupt();
         // block until the other threads finish
         t1.join();
         t2.join();
      } catch (InterruptedException ex) {
         System.out.println(ex.toString());
      }
   }

   public void run() {
      try {
         System.out.print(Thread.currentThread().getName());
         System.out.println(" executing...");

         while(true) {
            Thread.sleep(500);
         }
      } catch(InterruptedException e) {
         Thread currThread = Thread.currentThread();
         System.out.print(currThread.getName());
         System.out.println(" interrupted:" + e.toString());

         // rethrow the exception
         throw new RuntimeException(e.getMessage());
      }
   } 
}

class NewThreadGroup extends ThreadGroup {

   NewThreadGroup(String n) {
      super(n);
   }

   NewThreadGroup(ThreadGroup parent, String n) {
      super(parent, n);
   }

   public void uncaughtException(Thread t, Throwable e) {
      System.out.println(t + " has unhandled exception:" + e);
   } 
} 

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]...
Thread-0 executing...
Thread-1 executing...
Thread-1Thread-0 interrupted:java.lang.InterruptedException: sleep interrupted
 interrupted:java.lang.InterruptedException: sleep interrupted
Thread[Thread-0,5,Parent ThreadGroup] has unhandled exception:java.lang.RuntimeException: sleep interrupted
Thread[Thread-1,5,Child ThreadGroup] has unhandled exception:java.lang.RuntimeException: sleep interrupted

子线程组和孙线程组对象中检查未处理异常的示例

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 uncaughtException() 方法。我们创建了一个新类 NewThreadGroup，它扩展了 ThreadGroup。它具有 uncaughtException() 方法的重写实现。使用 NewThreadGroup，我们正在创建父、子线程组和孙线程组对象。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。启动线程后，我们使用 interrupt() 方法调用来中断流程。处理 InterruptedException 后，我们将抛出一个 RuntimeException，最终由 uncaughtException() 方法处理。

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
    	 NewThreadGroup pThreadGroup = new NewThreadGroup("Parent ThreadGroup");
		 
         // create a child ThreadGroup for parent ThreadGroup
    	 NewThreadGroup cThreadGroup = new NewThreadGroup(pThreadGroup, "Child ThreadGroup");
		 
         // create a grandchild ThreadGroup for parent ThreadGroup
    	 NewThreadGroup gThreadGroup = new NewThreadGroup(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();
            
         try {
            Thread.sleep(500);
         } catch(InterruptedException ex) {}
         // interrupt the two threads
         t1.interrupt();
         t2.interrupt();
         // block until the other threads finish
         t1.join();
         t2.join();
      } catch (InterruptedException ex) {
         System.out.println(ex.toString());
      }
   }

   public void run() {
      try {
         System.out.print(Thread.currentThread().getName());
         System.out.println(" executing...");

         while(true) {
            Thread.sleep(500);
         }
      } catch(InterruptedException e) {
         Thread currThread = Thread.currentThread();
         System.out.print(currThread.getName());
         System.out.println(" interrupted:" + e.toString());

         // rethrow the exception
         throw new RuntimeException(e.getMessage());
      }
   } 
}

class NewThreadGroup extends ThreadGroup {

   NewThreadGroup(String n) {
      super(n);
   }

   NewThreadGroup(ThreadGroup parent, String n) {
      super(parent, n);
   }

   public void uncaughtException(Thread t, Throwable e) {
      System.out.println(t + " has unhandled exception:" + e);
   } 
} 

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]...
Thread-0 executing...
Thread-1 executing...
Thread-1Thread-0 interrupted:java.lang.InterruptedException: sleep interrupted
 interrupted:java.lang.InterruptedException: sleep interrupted
Thread[Thread-1,5,GrandChild ThreadGroup] has unhandled exception:java.lang.RuntimeException: sleep interrupted
Thread[Thread-0,5,Child ThreadGroup] has unhandled exception:java.lang.RuntimeException: sleep interrupted