UserRoleDAO.java 文件源码

/**
 * retrieves the list of roles for a given username.
 * 
 * @param username
 *            the username
 * @return userRoles the roles
 * 
 */
public static Set<String> getRoles(String username) {
    EntityManagerFactory emf = Persistence.createEntityManagerFactory("userData");
    EntityManager em = emf.createEntityManager();
    CriteriaBuilder cb = em.getCriteriaBuilder();
    CriteriaQuery<UserRole> q = cb.createQuery(UserRole.class);
    Root<UserRole> c = q.from(UserRole.class);
    q.select(c).where(cb.equal(c.get("username"), username));
    TypedQuery<UserRole> query = em.createQuery(q);
    List<UserRole> roles = query.getResultList();
    Set<String> userRoles = new HashSet<String>();
    em.close();
    for (UserRole role : roles)
        userRoles.add(role.getRoleName());
    return userRoles;
}