Posted on 2012-09-13 20:25
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package org.springside.examples.miniweb.dao.account;
import java.util.List;
import javax.persistence.EntityManager;
import javax.persistence.PersistenceContext;
import org.springframework.stereotype.Component;
import org.springside.examples.miniweb.entity.account.Group;
import org.springside.examples.miniweb.entity.account.User;
/**
* GroupDao的扩展行为实现类.
*/
@Component
public class GroupDaoImpl implements GroupDaoCustom {
private static final String QUERY_USER_BY_GROUPID = "select u from User u left join u.groupList g where g.id=?";
@PersistenceContext
private EntityManager em;
@Override
public void deleteWithReference(Long id) {
//因為Group中沒有与User的关联，只能用笨办法，查询出拥有该权限组的用户, 并删除该用户的权限组.
Group group = em.find(Group.class, id);
List<User> users = em.createQuery(QUERY_USER_BY_GROUPID).setParameter(1, id).getResultList();
for (User u : users) {
u.getGroupList().remove(group);
}
em.remove(group);
}
}