你不能这样做，因为这真的没有意义。如果您没有调用t.join()，那么当t线程抛出异常时，主线程可能位于代码中的任何位置。

这是因为异常是线程本地的，主线程实际上看不到run方法。我建议您阅读更多关于线程如何工作的内容，但快速总结一下:调用start将启动一个与主线程完全无关的不同线程。对join的调用只是等待它完成。在线程中抛出且从未被捕获的异常将终止它，这就是为什么join在主线程上返回，但异常本身丢失的原因。

如果你想知道这些未捕获的异常，你可以试试这个:

Thread.setDefaultUncaughtExceptionHandler(new Thread.UncaughtExceptionHandler() {
    @Override
    public void uncaughtException(Thread t, Throwable e) {
        System.out.println("Caught " + e);
    }
});

关于未捕获异常处理的更多信息可以在这里找到。

使用Callable而不是Thread，然后你可以调用Future#get()，它会抛出Callable抛出的任何异常。

请看看Thread。UncaughtExceptionHandler

更好的(替代)方法是使用Callable和Future来获得相同的结果…

你玩了setDefaultUncaughtExceptionHandler()和线程类的类似方法吗?来自API:“通过设置默认的未捕获异常处理程序，应用程序可以为那些已经接受系统提供的任何“默认”行为的线程更改未捕获异常的处理方式(例如记录到特定设备或文件)。”

你可能会在那里找到问题的答案……好运！: -)

这解释了线程的状态转换取决于是否发生异常:

来源:http://www-public.imtbs-tsp.eu/~gibson/Teaching/CSC7322/L8-ExceptionsAndThreads.pdf

扩展Thread几乎总是错误的。我怎么强调都不为过。

多线程规则1:扩展线程是错误的

如果您实现Runnable，您将看到您预期的行为。

public class Test implements Runnable {

  public static void main(String[] args) {
    Test t = new Test();
    try {
      new Thread(t).start();
    } catch (RuntimeException e) {
      System.out.println("** RuntimeException from main");
    }

    System.out.println("Main stoped");

  }

  @Override
  public void run() {
    try {
      while (true) {
        System.out.println("** Started");

        Thread.sleep(2000);

        throw new RuntimeException("exception from thread");
      }
    } catch (RuntimeException e) {
      System.out.println("** RuntimeException from thread");
      throw e;
    } catch (InterruptedException e) {

    }
  }
}

产生;

Main stoped
** Started
** RuntimeException from threadException in thread "Thread-0" java.lang.RuntimeException: exception from thread
    at Test.run(Test.java:23)
    at java.lang.Thread.run(Thread.java:619)

除非你想改变你的应用程序使用线程的方式，在99.9%的情况下你不会这样做。如果你认为你属于0.1%的情况，请参阅规则1。

最有可能的;

您不需要将异常从一个线程传递到另一个线程。 如果你想处理异常，只需在抛出异常的线程中处理即可。 在本例中，主线程不需要从后台线程等待，这实际上意味着您根本不需要后台线程。

但是，让我们假设您确实需要处理来自子线程的异常。我将像这样使用ExecutorService:

ExecutorService executor = Executors.newSingleThreadExecutor();
Future<Void> future = executor.submit(new Callable<Void>() {
    @Override
    public Void call() throws Exception {
        System.out.println("** Started");
        Thread.sleep(2000);
        throw new IllegalStateException("exception from thread");
    }
});
try {
    future.get(); // raises ExecutionException for any uncaught exception in child
} catch (ExecutionException e) {
    System.out.println("** RuntimeException from thread ");
    e.getCause().printStackTrace(System.out);
}
executor.shutdown();
System.out.println("** Main stopped");

打印

** Started
** RuntimeException from thread 
java.lang.IllegalStateException: exception from thread
    at Main$1.call(Main.java:11)
    at Main$1.call(Main.java:6)
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303)
    at java.util.concurrent.FutureTask.run(FutureTask.java:138)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908)
    at java.lang.Thread.run(Thread.java:662)
** Main stopped

使用Thread.UncaughtExceptionHandler。

Thread.UncaughtExceptionHandler h = new Thread.UncaughtExceptionHandler() {
    @Override
    public void uncaughtException(Thread th, Throwable ex) {
        System.out.println("Uncaught exception: " + ex);
    }
};
Thread t = new Thread() {
    @Override
    public void run() {
        System.out.println("Sleeping ...");
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            System.out.println("Interrupted.");
        }
        System.out.println("Throwing exception ...");
        throw new RuntimeException();
    }
};
t.setUncaughtExceptionHandler(h);
t.start();

如果你实现Thread。在启动线程的类UncaughtExceptionHandler中，你可以设置并重新抛出异常:

public final class ThreadStarter implements Thread.UncaughtExceptionHandler{

private volatile Throwable initException;

    public void doSomeInit(){
        Thread t = new Thread(){
            @Override
            public void run() {
              throw new RuntimeException("UNCAUGHT");
            }
        };
        t.setUncaughtExceptionHandler(this);

        t.start();
        t.join();

        if (initException != null){
            throw new RuntimeException(initException);
        }

    }

    @Override
    public void uncaughtException(Thread t, Throwable e) {
        initException =  e;
    }    

}

这将导致以下输出:

Exception in thread "main" java.lang.RuntimeException: java.lang.RuntimeException: UNCAUGHT
    at com.gs.gss.ccsp.enrichments.ThreadStarter.doSomeInit(ThreadStarter.java:24)
    at com.gs.gss.ccsp.enrichments.ThreadStarter.main(ThreadStarter.java:38)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
    at java.lang.reflect.Method.invoke(Method.java:597)
    at com.intellij.rt.execution.application.AppMain.main(AppMain.java:120)
Caused by: java.lang.RuntimeException: UNCAUGHT
    at com.gs.gss.ccsp.enrichments.ThreadStarter$1.run(ThreadStarter.java:15)

Exception handling in Thread : By default run() method doesn’t throw any exception, so all checked exceptions inside the run method has to be caught and handled there only and for runtime exceptions we can use UncaughtExceptionHandler. UncaughtExceptionHandler is an interface provided by Java to handle exceptions in a Thread run method. So we can implement this interface and set back our implementing class back to Thread object using setUncaughtExceptionHandler() method. But this handler has to be set before we call start() on the tread.

如果我们不设置uncaughtExceptionHandler，那么线程线程组就会充当一个处理程序。

 public class FirstThread extends Thread {

int count = 0;

@Override
public void run() {
    while (true) {
        System.out.println("FirstThread doing something urgent, count : "
                + (count++));
        throw new RuntimeException();
    }

}

public static void main(String[] args) {
    FirstThread t1 = new FirstThread();
    t1.setUncaughtExceptionHandler(new UncaughtExceptionHandler() {
        public void uncaughtException(Thread t, Throwable e) {
            System.out.printf("Exception thrown by %s with id : %d",
                    t.getName(), t.getId());
            System.out.println("\n"+e.getClass());
        }
    });
    t1.start();
}
}

http://coder2design.com/thread-creation/#exceptions给出了很好的解释

目前您只捕获RuntimeException, Exception的一个子类。但是您的应用程序可能会抛出Exception的其他子类。捕获除RuntimeException之外的泛型异常

由于线程前端已经改变了许多东西，请使用高级java API。

优先选择高级java.util.concurrent API用于多线程，如ExecutorService或ThreadPoolExecutor。

您可以自定义ThreadPoolExecutor来处理异常。

示例来自oracle文档页:

覆盖

protected void afterExecute(Runnable r,
                            Throwable t)

方法，在完成给定可运行对象的执行时调用。此方法由执行任务的线程调用。如果非null，则Throwable是导致执行突然终止的未捕获的RuntimeException或Error。

示例代码:

class ExtendedExecutor extends ThreadPoolExecutor {
   // ...
   protected void afterExecute(Runnable r, Throwable t) {
     super.afterExecute(r, t);
     if (t == null && r instanceof Future<?>) {
       try {
         Object result = ((Future<?>) r).get();
       } catch (CancellationException ce) {
           t = ce;
       } catch (ExecutionException ee) {
           t = ee.getCause();
       } catch (InterruptedException ie) {
           Thread.currentThread().interrupt(); // ignore/reset
       }
     }
     if (t != null)
       System.out.println(t);
   }
 }

用法:

ExtendedExecutor service = new ExtendedExecutor();

我在上面的代码中添加了一个构造函数:

 public ExtendedExecutor() { 
       super(1,5,60,TimeUnit.SECONDS,new ArrayBlockingQueue<Runnable>(100));
   }

您可以更改此构造函数以满足您对线程数量的要求。

ExtendedExecutor service = new ExtendedExecutor();
service.submit(<your Callable or Runnable implementation>);

我用RxJava的解决方案:

@Test(expectedExceptions = TestException.class)
public void testGetNonexistentEntry() throws Exception
{
    // using this to work around the limitation where the errors in onError (in subscribe method)
    // cannot be thrown out to the main thread
    AtomicReference<Exception> ex = new AtomicReference<>();
    URI id = getRandomUri();
    canonicalMedia.setId(id);

    client.get(id.toString())
        .subscribe(
            m ->
                fail("Should not be successful"),
            e ->
                ex.set(new TestException()));

    for(int i = 0; i < 5; ++i)
    {
        if(ex.get() != null)
            throw ex.get();
        else
            Thread.sleep(1000);
    }
    Assert.fail("Cannot find the exception to throw.");
}

我也遇到过同样的问题……很少的工作(只用于实现而不是匿名对象)…我们可以将类级异常对象声明为null…然后在catch块for run方法中初始化它…如果在run方法中有错误，这个变量不会为空。然后，我们可以对这个特定的变量进行空检查，如果它不是空，那么线程执行内部就有异常。

class TestClass implements Runnable{
    private Exception ex;

        @Override
        public void run() {
            try{
                //business code
               }catch(Exception e){
                   ex=e;
               }
          }

      public void checkForException() throws Exception {
            if (ex!= null) {
                throw ex;
            }
        }
}     

join()后调用checkForException()

同样在Java 8中，你可以把Dan Cruz的答案写成:

Thread t = new Thread(()->{
            System.out.println("Sleeping ...");
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                System.out.println("Interrupted.");
            }
            System.out.println("Throwing exception ...");
            throw new RuntimeException(); });


t.setUncaughtExceptionHandler((th, ex)-> log(String.format("Exception in thread %d id: %s", th.getId(), ex)));
t.start();

AtomicReference也是一个将错误传递给主线程的解决方案。与Dan Cruz的方法相同。

AtomicReference<Throwable> errorReference = new AtomicReference<>();

    Thread thread = new Thread() {
        public void run() {
            throw new RuntimeException("TEST EXCEPTION");

        }
    };
    thread.setUncaughtExceptionHandler((th, ex) -> {
        errorReference.set(ex);
    });
    thread.start();
    thread.join();
    Throwable newThreadError= errorReference.get();
    if (newThreadError!= null) {
        throw newThreadError;
    }  

唯一的变化是你可以使用AtomicReference而不是创建一个volatile变量，它在幕后做了同样的事情。

对于那些需要停止所有线程运行，并在其中任何一个线程在异常上停止时重新运行所有线程的人:

@Override
public void onApplicationEvent(ContextRefreshedEvent event) {

     // could be any function
     getStockHistory();

}


public void getStockHistory() {

     // fill a list of symbol to be scrapped
     List<String> symbolListNYSE = stockEntityRepository
     .findByExchangeShortNameOnlySymbol(ContextRefreshExecutor.NYSE);


    storeSymbolList(symbolListNYSE, ContextRefreshExecutor.NYSE);

}


private void storeSymbolList(List<String> symbolList, String exchange) {

    int total = symbolList.size();

    // I create a list of Thread 
    List<Thread> listThread = new ArrayList<Thread>();

    // For each 1000 element of my scrapping ticker list I create a new Thread
    for (int i = 0; i <= total; i += 1000) {
        int l = i;

        Thread t1 = new Thread() {

            public void run() {

                // just a service that store in DB my ticker list
                storingService.getAndStoreStockPrice(symbolList, l, 1000, 
                MULTIPLE_STOCK_FILL, exchange);

            }

        };

    Thread.UncaughtExceptionHandler h = new Thread.UncaughtExceptionHandler() {
            public void uncaughtException(Thread thread, Throwable exception) {

                // stop thread if still running
                thread.interrupt();

                // go over every thread running and stop every one of them
                listThread.stream().forEach(tread -> tread.interrupt());

                // relaunch all the Thread via the main function
                getStockHistory();
            }
        };

        t1.start();
        t1.setUncaughtExceptionHandler(h);

        listThread.add(t1);

    }

}

总结如下:

你有一个主函数来创建多个线程，每个线程都有UncaughtExceptionHandler，由线程内的任何异常触发。将每个线程添加到一个列表中。如果一个UncaughtExceptionHandler被触发，它将循环遍历列表，停止每个线程并重新启动主函数重新创建所有线程。