据我所知，top不是JPQA关键字，它只在支持的DB中本地可用-参见this answer
看起来您的选择是这样，即滥用Pageable

@Query("SELECT new rtn.domain.common.structs.Payment(p.id, entryDate, paymentDate, ...)"
            + " from SomeTable" 
            + " where p.state = 'P'")
    List<Payment> findByTopN(Pageable pageable);
}

在服务中，使用PageRequest，返回一个Page对象：

Page<Payment> paymentsPage = paymentRepositoryJpa.findByTop(PageRequest.of(0, top));
List<Payment> payments= paymentsPage.getContent();

或者这个，它利用setMaxResults()：

List<Payment> findTopN(@Param("top") int  top) {
    return entityManager.createQuery("SELECT new rtn.domain.common.structs.Payment(p.id, entryDate, paymentDate, ...)"
            + " from SomeTable" 
            + " where p.state = 'P'",
      Payment.class).setMaxResults(top).getResultList();
}

一种解决方法是像这样使用CriteriaBuilder：

public List<Payment> findPendingPayments(int top) {
    CriteriaBuilder cb = entityManager.getCriteriaBuilder();
    CriteriaQuery<Payment> query = cb.createQuery(Payment.class);
    Root<Payment> payment = query.from(Payment.class);

    query.select(payment);

    return entityManager
            .createQuery(query)
                .setFirstResult(0) // offset
                .setMaxResults(top) // limit
                .getResultList();
}