Hibernate JPA 如何使用SQL文直接查询

对于复杂SQL，可以直接调用native sql来是实现

 public List<Partner> findPartners() {
        List<Partner> partnerList = new ArrayList<>();
        // 这里的em是注入的EntityManager
        List<Object> partners = this.em.createNativeQuery("select id, no, name from partner").getResultList();

        for(Object obj : partners){
            Object[] objArray = this.convertToObjectArray(obj);

            Partner partner = new Partner();
            partner.setId(objArray[0].toString());
            partner.setNo(objArray[1].toString());
            partner.setName(objArray[2].toString());

            partnerList.add(partner);
        }

        return partnerList;
    }

   // 将Object转化为数组
    private Object[] convertToObjectArray(Object array) {
        Class ofArray = array.getClass().getComponentType();
        if (ofArray.isPrimitive()) {
            List ar = new ArrayList();
            int length = Array.getLength(array);
            for (int i = 0; i < length; i++) {
                ar.add(Array.get(array, i));
            }
            return ar.toArray();
        }
        else {
            return (Object[]) array;
        }
    }