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jXee:
lgs0626 写道求源码,兄弟给共享下吧 "jee ...
jee6 学习笔记 4 - CRUD 2: View Details, Primefaces row selection -
lgs0626:
求源码,兄弟给共享下吧
jee6 学习笔记 4 - CRUD 2: View Details, Primefaces row selection
DAO interface.
DAO implemented as an EJB3.1 Stateless bean
小姐一下(本文不得不承认,windows中文输入很邪恶 ):
1。 从EJB3.0开始,开发EJB已经非常方便了。不需要处理lifecycle,不需要进行讨厌的xml配置,利用annotation很容易。做个譬喻:都是土豆,但ejb2是带泥的土豆,而ejb3则不带泥了,洗巴的干干净净,多好。EJBs阿POJOs,测试起来也比较容易了吧。。。如果你测试上瘾的话, 哈哈。。。
2。 DI 很方便,死脑筋(spring)还有什么优势?真是三十年河东,又三十年河西。
3。 JPA在ORM架子上又抽象了一下,提供标准的API,这多舒坦啊,别再折腾XML了!
下一篇 CRUD 一下: jee6 学习笔记 4 - CRUD
package com.jxee.ejb; import javax.ejb.Local; import com.jxee.model.User; /** * although it's not required, it's good practice to define a DAO interface. * annotation @Local marks this as an EJB local interface. */ @Local public interface UserDAO { public User findUserByName(String username); }
DAO implemented as an EJB3.1 Stateless bean
package com.jxee.ejb; import javax.ejb.Stateless; import javax.persistence.EntityManager; import javax.persistence.PersistenceContext; import javax.persistence.Query; import org.apache.log4j.Logger; import com.jxee.model.User; /** * annotation @Stateless marks a POJO as a stateless EJB and thus it * would have all the services available, like transaction management etc. */ @Stateless public class UserDAOImp implements UserDAO { private static final Logger log = Logger.getLogger(UserDAOImp.class); // inject the persistence unit to have access to database @PersistenceContext(unitName="punit.projee6") private EntityManager em; // @EJB AnotherEJB toInjectOtherEJB; /** * method throws runtime exception like "NoResultException" and * "NonUniqueResultException" etc, which you dont need to handle. * but you might want to handle it, such as "NoResultException". */ public User findUserByName(String username) { log.debug("finding user for name: " + username); String sql = "select u from User u where u.username = :username"; Query query = em.createQuery(sql); query.setParameter("username", username); return (User)query.getSingleResult(); // may throw runtime exceptions } }
小姐一下(本文不得不承认,windows中文输入很邪恶 ):
1。 从EJB3.0开始,开发EJB已经非常方便了。不需要处理lifecycle,不需要进行讨厌的xml配置,利用annotation很容易。做个譬喻:都是土豆,但ejb2是带泥的土豆,而ejb3则不带泥了,洗巴的干干净净,多好。EJBs阿POJOs,测试起来也比较容易了吧。。。如果你测试上瘾的话, 哈哈。。。
2。 DI 很方便,死脑筋(spring)还有什么优势?真是三十年河东,又三十年河西。
3。 JPA在ORM架子上又抽象了一下,提供标准的API,这多舒坦啊,别再折腾XML了!
下一篇 CRUD 一下: jee6 学习笔记 4 - CRUD
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