Hibernate HQL查詢的一點小結

HQL動態查詢

    public List<PlayList> testDynamicQuery(Integer flag ,String tags) {
            StringBuilder queryCondition = new StringBuilder("");
            if(flag != null){
                queryCondition.append(" and p.flag = "+ flag);
            }
            if(tags != null && tags.length() > 0){
                queryCondition.append(" and p.tags =" +"'"+tags+"'");//String類型特殊處理
            }
            String hql = "select p from PlayList p , VedioRecommend v 
                                    where  p.filmId = v.id"+ queryCondition;
            Query query = getSession().createQuery(hql);
            return query.list();
        }

Object[] 數組接收部分參數

    public List<Object[]> testObject() {
        String hql = "select p.filmName,p.season from PlayList p";
        Query query = getSession().createQuery(hql);
        return query.list();
    }

Map接收部分參數

    public List<Map<String, Object>> testMap() {
        String hql = "select new map(p.filmName as name,p.season as season) from PlayList p";
        Query query = getSession().createQuery(hql);
        return query.list();
    }

    注：Map 必須用小寫 map，key 默認爲"0","1","2"... 但是用as給出的別名將作爲key;

DTO對象接收部分參數

    @PersistenceContext
    private EntityManager em;
    @Override
    public List<UserInfoVo> findUserInfoVo() {
        String hql = "select new com.demo.provideruser.dto.UserInfoVo(u.id ,u.name ,u.age )  from User u order by u.id";
        Query query = em.createQuery(hql);
        return query.getResultList();
    }