Java 线程池异常处理：如何捕获 ThreadPoolExecutor 内部线程异常？

方案 1

使用 execute + try-catch 记录异常

import java.util.concurrent.*;

public class ThreadPoolExceptionDemo {
    public static void main(String[] args) {
        ThreadPoolExecutor executor = new ThreadPoolExecutor(
                2, 4, 10, TimeUnit.SECONDS,
                new LinkedBlockingQueue<>(),
                new ThreadFactory() {
                    private int count = 1;
                    @Override
                    public Thread newThread(Runnable r) {
                        return new Thread(r, "custom-thread-" + count++);
                    }
                });

        executor.execute(() -> {
            try {
                System.out.println(Thread.currentThread().getName() + " 正在执行任务");
                throw new RuntimeException("任务异常");
            } catch (Exception e) {
                System.err.println("线程 " + Thread.currentThread().getName() + " 捕获异常: " + e.getMessage());
                e.printStackTrace();
            }
        });

        executor.shutdown();
    }
}

方案 2

使用 submit + Future

submit() 方法返回 Future，可以通过 get() 方法捕获异常：

public static void main(String[] args) {
    ExecutorService executor = Executors.newFixedThreadPool(2);

    Future<?> future = executor.submit(() -> {
        System.out.println(Thread.currentThread().getName() + " 正在执行任务");
        throw new RuntimeException("任务异常");
    });

    try {
        future.get(); // get() 会抛出 ExecutionException
    } catch (InterruptedException | ExecutionException e) {
        System.err.println("线程 " + Thread.currentThread().getName() + " 捕获异常: " + e.getCause().getMessage());
        e.printStackTrace();
    }

    executor.shutdown();
}

注意

• get() 方法会阻塞主线程直到任务完成。
• ExecutionException 的 getCause() 方法可以获取原始异常。

方案 3

自定义 UncaughtExceptionHandler

可以为线程设置 UncaughtExceptionHandler，当 Runnable 没有捕获异常时，ThreadPoolExecutor 也不会吞掉异常：

public class ThreadPoolWithExceptionHandler {
    public static void main(String[] args) {
        ThreadFactory threadFactory = r -> {
            Thread t = new Thread(r);
            t.setUncaughtExceptionHandler((thread, throwable) -> {
                System.err.println("线程 " + thread.getName() + " 发生异常: " + throwable.getMessage());
                throwable.printStackTrace();
            });
            return t;
        };

        ExecutorService executor = new ThreadPoolExecutor(
                2, 4, 10, TimeUnit.SECONDS,
                new LinkedBlockingQueue<>(),
                threadFactory
        );

        executor.execute(() -> {
            System.out.println(Thread.currentThread().getName() + " 正在执行任务");
            throw new RuntimeException("任务异常");
        });

        executor.shutdown();
    }
}

方案 4

重写 afterExecute 方法

如果你要在 ThreadPoolExecutor 内部直接处理异常，可以继承 ThreadPoolExecutor 并重写 afterExecute()：

class CustomThreadPoolExecutor extends ThreadPoolExecutor {
    public CustomThreadPoolExecutor(int corePoolSize, int maximumPoolSize, long keepAliveTime, TimeUnit unit, BlockingQueue<Runnable> workQueue) {
        super(corePoolSize, maximumPoolSize, keepAliveTime, unit, workQueue);
    }

    @Override
    protected void afterExecute(Runnable r, Throwable t) {
        super.afterExecute(r, t);
        if (t == null && r instanceof Future<?>) {
            try {
                ((Future<?>) r).get(); // 获取任务结果，捕获异常
            } catch (InterruptedException | ExecutionException e) {
                t = e.getCause();
            }
        }
        if (t != null) {
            System.err.println("线程 " + Thread.currentThread().getName() + " 发生异常: " + t.getMessage());
            t.printStackTrace();
        }
    }
}

public class ThreadPoolAfterExecuteDemo {
    public static void main(String[] args) {
        ThreadPoolExecutor executor = new CustomThreadPoolExecutor(2, 4, 10, TimeUnit.SECONDS, new LinkedBlockingQueue<>());

        executor.submit(() -> {
            System.out.println(Thread.currentThread().getName() + " 正在执行任务");
            throw new RuntimeException("任务异常");
        });

        executor.shutdown();
    }
}

结论

方案	适用场景	缺点
try-catch 手动处理	适用于 execute()	代码侵入性强，所有任务都要加 try-catch
Future.get() 捕获异常	适用于 submit()	get() 会阻塞主线程
UncaughtExceptionHandler	适用于 execute()	不能捕获 submit() 提交的异常
afterExecute()	适用于 execute() 和 submit()	需要继承 ThreadPoolExecutor

推荐：

• 任务内部 try-catch 适用于 execute()
• Future.get() 适用于 submit()
• 统一异常处理建议使用 afterExecute() 或 UncaughtExceptionHandler