MethodValidationPostProcessor中断@Transactional

Question

我有一个Controller，它调用一个具有@Transactional注释的Service。

但是，当我声明bean MethodValidationPostProcessor时，no事务被创建了(无法初始化代理-没有会话)。

@EnableWebMvc
@ComponentScan(basePackages = {"my"})
public class Application extends WebMvcConfigurerAdapter {
    @Bean
    public MethodValidationPostProcessor methodValidationPostProcessor() {
        return new MethodValidationPostProcessor();
    }
}

控制器bean：

@RestController
@RequestMapping(path = "/my", produces = APPLICATION_JSON_VALUE)
public class MyController {

    @Autowired
    private TransactionalService transactionalService;

    @RequestMapping(method = POST)
    public void post(@SafeHtml @RequestBody String hey) {
        transactionalService.doStuff(hey);
    }
}

服务bean：

@Service
public class TransactionalService {

    @PersistenceContext
    private EntityManager entityManager;

    @Transactional
    public void doStuff(String hey) {
        Item h = entityManager.find(Item.class, hey);
        h.getParent(); // could not initialize proxy - no Session
    }

}

当我声明@Transactional时，我想了解为什么MethodValidationPostProcessor不能工作。谢谢！

注意:如果我在我的Controller上添加了“事务处理”，它就能工作。但这不是我想做的。

Answer 1

多亏了@Kakawait，我找到了一个解决方案:声明我的bean MethodValidationPostProcessor。需要是static，这样@Transactional仍能正常工作。

/**
 * This bean must be static, to be instantiated before the other MethodValidationPostProcessors.
 * Otherwise, some are not instantiated.
 */
@Bean
public static MethodValidationPostProcessor methodValidationPostProcessor() {
    return new MethodValidationPostProcessor();
}