java - 在 AsyncUncaughtExceptionHandler 中获取 Hibernate Session

Question

当 @Async 操作因异常而失败时，我想在数据库中创建一个异常日志。

您可以在下面看到 AsyncExecutorConfiguration 和 AsyncExceptionHandler 类的实现。

在 AsyncExceptionHandler 类中，当我调用试图访问数据库的服务时，我得到:org.hibernate.HibernateException: Could not obtain transaction-synchronized Session for current thread

@Configuration
@EnableAsync
public class AsyncExecutorConfiguration implements AsyncConfigurer {

    @Autowired
    private AsyncExceptionHandler asyncExceptionHandler;

    private static final int CORE_POOL_SIZE = 3;
    private static final int MAX_POOL_SIZE = 3;
    private static final int QUEUE_CAPACITY = 24;
    private static final String THREAD_NAME_PREFIX = "AsynchThread-";

    @Override
    public Executor getAsyncExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setCorePoolSize(CORE_POOL_SIZE);
        executor.setMaxPoolSize(MAX_POOL_SIZE);
        executor.setQueueCapacity(QUEUE_CAPACITY);
        executor.setThreadNamePrefix(THREAD_NAME_PREFIX);
        executor.initialize();
        return executor;
    }

    @Override
    public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler() {
        return asyncExceptionHandler;
    }

}

@Component
public class AsyncExceptionHandler implements AsyncUncaughtExceptionHandler {
    @Autowired
    private NotificationService notificationService;

    @Override
    @Transactional(rollbackFor = Exception.class, readOnly = false)
    public void handleUncaughtException(Throwable ex, Method method, Object... params) {
        AsyncErrorLog log = new AsyncErrorLog(ex);
        notificationService.saveLogAndNotify(log); // throws exception "Could not obtain transaction-synchronized Session for current thread"
    }
}


@Service
public class MyServiceImpl implements MyService {

    @Override
    @Async
    @Transactional(rollbackFor = Exception.class, readOnly = false, propagation = Propagation.REQUIRES_NEW)
    public void doSomething(Long id) {
        // I can execute database operations here

    }
    ...

@Async 函数本身已经有一个有效的 session 。我应该怎么做才能在 AsyncExceptionHandler 类中也有一个有效的 session ？

--

更新

这里是我们得到错误的 NotificationServiceImpl 和 LogDaoImpl.class 的简化实现。

@Service
public class NotificationServiceImpl implements NotificationService {

    @Autowired
    private LogDao logDao;

    @Override
    @Transactional(rollbackFor = Exception.class, readOnly = false)
    public void saveLogAndNotify(Log log) {
        return logDao.createLog(log);
    }


@Repository
public class LogDaoImpl{

    @Autowired
    protected SessionFactory sessionFactory;


    @Override
    public void createLog(Log log) {
        sessionFactory.getCurrentSession().saveOrUpdate(log);
    }

Answer 1

根据 Hibernate 异常；如果您不使用 Spring Data，则必须确保通知服务在 Hibernate session 中显式调用数据库。

另一方面，根据我的经验，UncaughtExceptionHandler 的主要用例(通常)用于:

1. 一个简单的最后手段来处理程序员可能不知道的 RuntimeException，由于某种原因不能(或没有)在代码中捕获
2. 一种在程序员无法控制的代码中捕获异常的方法(例如，如果您直接在某些第三方库上调用 Async，等等)

两者的共同点是这个Handler是用来做一些意想不到的事情的。事实上，Spring 本身会解释您自己的代码和 Spring Async 中的“意外情况”已经 sets a default one for you that will log to the console (代码 here )，让您不必担心流氓异常杀死线程并且不知道为什么。 (注意:源代码中的消息说它捕获了一个“意外”异常。当然异常是意外的，但这些是你真的不知道会发生的。Spring Async 将记录它给你。)

既然如此，在您的示例中，由于您正在执行 Spring 数据库操作并且应该确切地知道 #doSomething 内部发生了什么，所以我会删除 AUEH a try-catch(和/或-finally)并处理#doSomething 中的异常:

@Service
public class MyServiceImpl implements MyService {

    // Self autowired class to take advantage of proxied methods in the same class
    // See https://stackoverflow.com/questions/51922604/transactional-and-stream-in-spring/51923214#51923214
    private MyService myService;  

    private NotificationService notificationService;  

    @Override
    @Async
    public void doSomething(Long id) {
        // I can execute database operations here
        try {
            myService.doDatabaseOperations(...);
        } catch(DatabaseAccessException e) {
            AsyncErrorLog log = new AsyncErrorLog(ex);
            notificationService.saveLogAndNotify(log);
        }
        // Other exceptions (from DB operations or the notifications service) can be 
        // handled with other "catches" or to let the SimpleAsyncExHandler log them for you.
        // You can also use standard multithreading exception handling for this
    }

    @Transactional(rollbackFor = Exception.class, readOnly = false, propagation = Propagation.REQUIRES_NEW)
    public void doDatabaseOperations(...) {
        ...
    }

}