使用JSF，JPA和DAO.没有春天?

问题描述

直到现在，我仍然在没有DAO的情况下仍与JSF和JPA一起工作.现在，我想使用DAO.但是如何在DAO类中初始化EntityManager?

public class AdresseHome {

    @PersistenceContext
    private EntityManager entityManager;

    public void persist(Adresse transientInstance) {
        log.debug("persisting Adresse instance");
        try {
            entityManager.persist(transientInstance);
            log.debug("persist successful");
        } catch (RuntimeException re) {
            log.error("persist failed", re);
            throw re;
        }
    }
}

我是否使用过Spring，还是有没有Spring的解决方案?

谢谢.

解决方案

如果您的容器没有为您注入EntityManager，则可以使用以下方法获得一个:

EntityManagerFactory factory;
factory = Persistence.createEntityManagerFactory("jpatest");
EntityManager em = factory.createEntityManager();

在persistence.xml中定义的单元的"jpatest"中

till now i still worked with JSF and JPA without DAOs. Now i'd like to use DAOs. But how can i initialize the EntityManager in the DAO-Classes?

public class AdresseHome {

    @PersistenceContext
    private EntityManager entityManager;

    public void persist(Adresse transientInstance) {
        log.debug("persisting Adresse instance");
        try {
            entityManager.persist(transientInstance);
            log.debug("persist successful");
        } catch (RuntimeException re) {
            log.error("persist failed", re);
            throw re;
        }
    }
}

Have I to use Spring or is there a solution that works without Spring?

Thanks.

解决方案

If your container doesn't inject the EntityManager for you, you can get one with:

EntityManagerFactory factory;
factory = Persistence.createEntityManagerFactory("jpatest");
EntityManager em = factory.createEntityManager();

Where "jpatest" from the unit defined in your persistence.xml

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