【Java技术指南】「技术盲区」看看线程以及线程池的异常处理机制都有哪些？

public class ThreadSample implements Runnable {
    @Override
    public void run() {  //run()方法上不可以抛出异常
        System.out.println("任务开始执行");
        try {
            Thread.sleep(1000);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        int i = 10 /0;  //这里抛出RuntimeException()
        System.out.println("任务执行结束");
    }
}
public class ThreadErrorTest {
    public static void main(String[] args) {
        Thread a = new Thread(new ThreadSample());
        a.start();
        System.out.println("主线程执行结束！！！");
    }
}
复制代码

public class ThreadErrorTest {
    public static void main(String[] args) {
        Thread a = new Thread(new ThreadSample());
        a.setUncaughtExceptionHandler(new RuntimeExceptionHandle());
        a.start();
        System.out.println("主线程执行结束！！！");
    }
}
public class RuntimeExceptionHandle implements Thread.UncaughtExceptionHandler {
    @Override
    public void uncaughtException(Thread t, Throwable e) {
        //打印异常信息到日志
        System.out.println("异常处理器调用, 打印日志: " + e);
    }
}
复制代码

public void run() {
   try {
    //处理逻辑
   } catch(Exeception e) {
      //打印日志
    }
}
复制代码

public class MyThreadPool extends ThreadPoolExecutor {
    public MyThreadPool(int corePoolSize, int maximumPoolSize,
                        long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue) {
        super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue);
    }
    @Override
    public void afterExecute(Runnable r, Throwable t) {
        if(t != null) {
            System.out.println("打印异常日志：" + t);
        }
    }
}
复制代码

public void execute(Runnable command) {
    if (command == null)
        throw new NullPointerException();
    int c = ctl.get();
    if (workerCountOf(c) < corePoolSize) {
        if (addWorker(command, true))
            return;
        c = ctl.get();
    }
    if (isRunning(c) && workQueue.offer(command)) {
        int recheck = ctl.get();
        if (! isRunning(recheck) && remove(command))
            reject(command);
        else if (workerCountOf(recheck) == 0)
            addWorker(null, false);
    }
    else if (!addWorker(command, false))
        reject(command);
}
/**
* addWorker方法部分内容
*/
w = new Worker(firstTask); //封装成Worker对象
final Thread t = w.thread;
if (t != null) {
    final ReentrantLock mainLock = this.mainLock;
    mainLock.lock();
    try {
        // Recheck while holding lock.
        // Back out on ThreadFactory failure or if
        // shut down before lock acquired.
        int rs = runStateOf(ctl.get());
        if (rs < SHUTDOWN ||
            (rs == SHUTDOWN && firstTask == null)) {
            if (t.isAlive()) // precheck that t is startable
                throw new IllegalThreadStateException();
            workers.add(w);
            int s = workers.size();
            if (s > largestPoolSize)
                largestPoolSize = s;
            workerAdded = true;
        }
    } finally {
        mainLock.unlock();
    }
    if (workerAdded) {
        t.start();
        workerStarted = true;
    }
/**
* worker对象里面的run方法部分内容
*/
while (task != null || (task = getTask()) != null) {
    w.lock();
     if ((runStateAtLeast(ctl.get(), STOP) ||
          (Thread.interrupted() &&
           runStateAtLeast(ctl.get(), STOP))) &&
         !wt.isInterrupted())
         wt.interrupt();
     try {
         beforeExecute(wt, task);
         Throwable thrown = null;
         try {
             task.run();
         } catch (RuntimeException x) {
             thrown = x; throw x;
         } catch (Error x) {
             thrown = x; throw x;
         } catch (Throwable x) {
             thrown = x; throw new Error(x);
         } finally {
             afterExecute(task, thrown); //执行改方法
         }
     } finally {
         task = null;
         w.completedTasks++;
         w.unlock();
     }
 }
复制代码

public Future<?> submit(Runnable task) {
        if (task == null) throw new NullPointerException();
        RunnableFuture<Void> ftask = newTaskFor(task, null);
        execute(ftask); //封装成FutureTask对象交给execute方法
        return ftask;
}
复制代码

public void run() {
  if (state != NEW ||
       !UNSAFE.compareAndSwapObject(this, runnerOffset,
                                    null, Thread.currentThread()))
       return;
   try {
       Callable<V> c = callable;
       if (c != null && state == NEW) {
           V result;
           boolean ran;
           try {
               result = c.call();
               ran = true;
           } catch (Throwable ex) {
               result = null;
               ran = false;
               setException(ex);  //捕获异常
           }
           if (ran)
               set(result);
       }
   } finally{   ...... }
复制代码

public V get() throws InterruptedException, ExecutionException {
   int s = state;
     if (s <= COMPLETING)
         s = awaitDone(false, 0L);
     return report(s);
 }
private V report(int s) throws ExecutionException {
   Object x = outcome;
     if (s == NORMAL)
         return (V)x;
     if (s >= CANCELLED)
         throw new CancellationException();
     throw new ExecutionException((Throwable)x);
 }
复制代码

public class MyThreadFactory implements ThreadFactory {
    @Override
    public Thread newThread(Runnable r) {
        Thread t = new Thread(r);
        t.setUncaughtExceptionHandler(new RuntimeExceptionHandle());
        return t;
    }
}
复制代码

public class ThreadPoolExecption1 {
    private static ExecutorService executor = Executors.newSingleThreadExecutor(new MyThreadFactory());
    public static void main(String[] args) {
        Task task = new Task();
        executor.execute(task);
        executor.submit(task);
    }
}
复制代码

public class ThreadPoolException2 {
    private static ExecutorService executor = Executors.newFixedThreadPool(3);
    public static void main(String[] args) {
        Thread.setDefaultUncaughtExceptionHandler(new RuntimeExceptionHandle());
        Task task = new Task();
        executor.execute(task);
        //executor.submit(task);
    }
}