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我在玩交易。

我将 JPA 配置为处理我的实体，并希望将它们保存在数据库中。问题是，当我的程序抛出 runtimeException 时，CMT 不会回滚。

这个“容器的东西”背后的想法很难理解，而且文档记录也很差。

@transactional 托管事务、纯 CDI 拦截器托管事务和 Bean 托管事务的工作就像一个魅力。

这是我编码的内容：这是一个简单的“电影演示”。你想看两部 X 座位的电影。座位有限。如果电影中没有足够的席位，则不应该有交易（ACID 之类的）

在我的 buyTicketsBoundary 课程中：

起初我告诉我的班级我们正在使用 CMT：

@Named("buchungBoundry")
@RequestScoped
@TransactionManagement(TransactionManagementType.CONTAINER)
public class BuchungBoundry {

@EJB
private BuchungVerwaltung buyTicketsController;
@EJB
private KundenVerwaltung customerController;
@EJB
private SaalVerwaltung roomController;
@EJB
private MovieVerwaltung movieController;



private int ticketsForMovie1; //this is how many tickets we want to buy
private int ticketsForMovie2;

public BuchungBoundry() {
}

@TransactionAttribute(TransactionAttributeType.REQUIRED)
public void buyTickets() throws MyException {


    int numberOfSeantsInRoom1=roomController.getSaal(4).getAnzahlPlaetze();
    int numberOfSeantsInRoom2=roomController.getSaal(5).getAnzahlPlaetze();

    int alreadyBoughtSeatsIn1=buyTicketsController.getBelegtePlatzeNachSaal(4);
    int alreadyBoughtSeatsIn2=buyTicketsController.getBelegtePlatzeNachSaal(5);

    int availableSeats1 = numberOfSeantsInRoom1 - alreadyBoughtSeatsIn1;
    int availableSeats2 = numberOfSeantsInRoom2 - alreadyBoughtSeatsIn2;


    System.out.println("Saal A: ("+alreadyBoughtSeatsIn1+"/"+numberOfSeantsInRoom1+") want to buy :" + ticketsForMovie1);
    System.out.println("Saal B: ("+alreadyBoughtSeatsIn2+"/"+numberOfSeantsInRoom2+") want to buy :" + ticketsForMovie2);

    try {
        if (ticketsForMovie1 <= availableSeats1) {
        buyTicketsController.erstelleBuchung(customerController.getKunde(1),
                movieController.getMovie(7),
                roomController.getSaal(4),
                ticketsForMovie1);
        } else {
            throw new MyException("ERROR: no room for "
                    + ticketsForMovie1 + " person! "
                    +alreadyBoughtSeatsIn1);
        }
        if (ticketsForMovie2 <= availableSeats2) {
            buyTicketsController.erstelleBuchung(customerController.getKunde(1),
                    movieController.getMovie(8),
                    roomController.getSaal(5),
                    ticketsForMovie2);
        } else {
            throw new MyException("ERROR: no room for "
                    + ticketsForMovie2 + " person! "
                    +alreadyBoughtSeatsIn2);
        }

    } catch (MyException | IllegalStateException | SecurityException ex) {
        Logger.getLogger(BuchungBoundry.class.getName()).log(Level.SEVERE, null, ex);
    }
}

我的例外：

@ApplicationException(rollback=true)
public class MyException extends RuntimeException{
    public MyException()  {

    }

    public MyException(String s) {
        System.out.println(""+s);
    }
}

通过 JPA 在数据库中写入已购买票证的控制器类：

@Stateless
public class BuchungVerwaltung implements Serializable {

@PersistenceContext(unitName = "kbse-JTA")
private EntityManager em;

public BuchungVerwaltung() {
}

public void erstelleBuchung(Kunde k, Movie movie, Saal saal, int anzahlPlaetze) {
    Buchung b = new Buchung(k, movie, saal, anzahlPlaetze);
    em.persist(b);
}

public int getBelegtePlatzeNachSaal(int id) {
    try {
        Query query = em.createNativeQuery("select sum(b.ANZAHL) from SAAL s,BUCHUNG b where s.SAAL_ID = b.SAAL_SAAL_ID and s.SAAL_ID=?");
        query.setParameter(1, id);
        return (int) query.getSingleResult();
    } catch (Exception e) {
        return 0;
    }
}

public List<Buchung> getAlleBuchungen() {
    TypedQuery<Buchung> query = em.createQuery("select s from Buchung s", Buchung.class);
    return query.getResultList();
}
}

问题是，当此类达到第一部电影的 em.persist 状态，而第二部电影抛出异常时，数据库无法回滚。

我想如果抛出 RuntimeException，容器会回滚

我该怎么做才能让它发挥作用？

如果有不清楚的地方请告诉我

4

1 回答 1

0

我做的一切都是正确的，唯一的错误是捕捉到“myException”

} catch (MyException | IllegalStateException | SecurityException ex) {

} catch ( IllegalStateException | SecurityException ex) {

它现在可以工作了，容器可以像它应该的那样回滚

于 2014-05-25T00:34:18.303 回答