ejb - CDI + EJB 3 + EJB 事务

Question

我需要审核 ejb bean 的调用。说审计我的意思是将当前登录的用户、方法名称、附加描述等信息写入数据库。我决定使用 CDI 装饰器来做到这一点:

@Decorator
public class AccountServiceBeanDecorator implements AccountService {

  @Inject
  @Delegate
  @Any
  AccountService accountService;

  @EJB
  private AuditService auditService;

  @Override
  public Account createAccount(Account account) {
    auditService.saveAudit("Method: createAccount", currentUser, "Creating account by admin");
    return accountService.createAccount(account);
  }

}

和装饰类:

@Stateless
public class AccountServiceBean implements AccountService {

   @Override
   public Account createAccount(Account account) {
     ... 
   }
}

现在如果我从另一个 ejb 无状态 bean 调用 AccountService，事务会发生什么情况？

@Stateless
public ApplicationFacadeBean implements ApplicationFacade {

  @EJB
  private AccountService accountService;

  @Override
  public Account createAccount(Account account) {
    return accountService.createAccount(account);
  }

}

我想在装饰器 (AccountServiceBeanDecorator) 和装饰类 (AccountServiceBean) 中记录事务状态，因此我将 TransactionSynchronizationRegistry 作为资源注入(inject)到两个类中:

@Decorator
public class AccountServiceBeanDecorator implements AccountService {

  @Inject
  @Delegate
  @Any
  AccountService accountService;

  @EJB
  private AuditService auditService;

  @Resource
  private TransactionSynchronizationRegistry reg;

  @Override
  public Account createAccount(Account account) {
    log.info("%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%");
    log.info("tx ({}): {}", new Object[] {reg.getTransactionStatus(), reg.getTransactionKey()});
    log.info("%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%");
    auditService.saveAudit("Method: createAccount", currentUser, "Creating account by admin");
    return accountService.createAccount(account);
  }

}

和

@Stateless
public class AccountServiceBean implements AccountService {

   @Resource
   private TransactionSynchronizationRegistry reg;

   @Override
   public Account createAccount(Account account) {

    log.info("%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%");
    log.info("tx ({}): {}", new Object[] {reg.getTransactionStatus(), reg.getTransactionKey()});
    log.info("%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%");
     ... 
   }
}

我收到奇怪的行为:

• 装饰器日志

  tx (0): JavaEETransactionImpl: txId=6 nonXAResource=null jtsTx=null localTxStatus=0 syncs=[com.sun.ejb.containers.ContainerSynchronization@68fb15d0]]] 
  

• 第二个日志出现 NullPointerException(reg 为空)。

有人能给我解释一下吗？是否在与 ApplicationFacade 相同的事务中调用 AccountServiceBean 类？

谢谢

Answer 1

首先:我不会将 ejbs 与 cdi 拦截器混合使用。 ejbs 在拦截器实现上有它。

第二:拦截器与拦截器所在的ejb在同一个事务中执行。

可能的解决方案:

• 创建正确的 ejb 拦截器
• 将拦截器放在方法/类周围
• 使用像这样的方法创建第二个 ejb (MyLoggerBean) logToDatabase(String message) 并使用 @TransactionAttribute(TransactionAttributeType.REQUIRES_NEW)< 注释此方法/强>
• 在拦截器内部创建一个这样的类成员:@EJB private MyLoggerBean loggerBean
• 在您的 @AroundInvoke 注释方法中，您可以调用 loggerBean。 logToDatabase(...)

这将从拦截器所在的 ejb 的当前事务内部创建一个新事务

--> 我知道我的英语不是很好。但我希望你能理解我认为应该起作用的方法。如果我有时间，我会在 github 上做一个例子...