如何在使用Spring发送HTTP响应后执行数据库调用

Question

所以我基本上想在Spring中处理一个带有Controller的HTTP-Post，并在发送数据库之后向User发回一个结果。

所以这是我的例子：

@Controller
public class AngebotController extends WebMvcConfigurerAdapter {
    @Autowired
    private DatabaseUtils dbUtil;
    @Autowired
    private MyMailSender mailSender;

    @RequestMapping(value = REQUEST_PATH, method = RequestMethod.POST)
    public String doPost(@Valid FormInput input, BindingResult bindingResult) {
        // .. some input validations here
        // after the validation is complete i will have accesss to a object, that i just created, just like the following
        // Lets say that this object holds important values for the database query
        final MyObject validatedInput = new MyObject();

        // Start a new Thread to do the remaining work (the Database Call)
        Thread t = new Thread() {
            @Override
            public void run() {
                // so i am starting the database query with the information that i just validated above
                // That Database Query will Return a List of Items based on the given MyObject
                // This Query will take a long time and i dont want the user to wait, because this data is not nessessary for the user
                List<Item> items = dbUtil.getStuffByInput(validatedInput);
                for(Item i : items) {
                    // Now i just want to send some informations about the item via email, this part works
                    mailSender.sendMail("mail@mail.mail", i);
                }
            }
        }.start();

        return "viewname";
    }
}



@Service
public class DatabaseUtils {
    @Autowired
    private ItemRepository repository;

    public List<Item> getStuffByInput(MyObject o) {
        List<Item> items = repository.findAllByMyObject(o);
        // Doing some more stuff with those items here ..
        return items;
    }
}

// The Implementation will be generated by Spring
public interface ItemRepository extends CrudRepository<Item, Long> {
    // will select all Items by comparing the myObject with each Item
    // This also works like intended
    public List<Item> findAllByMyObject(MyObject myObject);
}

那我的问题在哪里？
我唯一的问题是，数据库查询将结束抛出异常，因为数据库连接已关闭（我猜是春天）

异常：线程“Thread-6”中的异常org.hibernate.SessionException：会话已关闭！

任何帮助表示赞赏。 谢谢！