下面是我的服务实现方法：

@Override
    public List<Question> getQuestion(Long questionId, int page, int records, String organizationId) throws InvalidIdException {

        Organization existingOrganization=organizationRepository.findOne(siteUtil.getDecryptedId(organizationId));
        Pageable pageInfo=new PageRequest(page-1,records);
        Page<com.oAssessment.entity.Question> existingQuestions=questionRepository.findAllByOrganizationAndDeleted
                (existingOrganization,false,pageInfo);
        List<Question> existingQuestion = new ArrayList<>();
        if(existingQuestions.hasContent()) {
            Iterator<com.oAssessment.entity.Question> existingQustionIterator = existingQuestions.iterator();
            while(existingQustionIterator.hasNext()) {
                com.oAssessment.entity.Question newQuestion = existingQustionIterator.next();
                Question question = new Question();
                if(newQuestion.getPkQuestionId()!=null) {
                    question.setSerialNo(newQuestion.getSerialNo());
                    question.setQuestionText(newQuestion.getText());
                    question.setDifLevel(newQuestion.getDifLevel());
                    question.setTypeOfquestion(newQuestion.getTypeOfQuestion());
                    existingQuestion.add(question);
                }
            }
        }
        return existingQuestion;
    }

jpa存储库应该是这样的

@Repository
public interface QuestionRepository extends JpaRepository<Question, Long> {

    Page<Question> findAllByOrganizationAndDeleted(Organization existingOrganization, boolean b, Pageable pageInfo);

}

这样，所有的数据都来自数据库。但我只想设置一些条件来过滤掉数据。就像我想从数据库中获取一些关于给定主题的问题，没有问题，问题的难度级别是这样的。但是这些数据应该是随机的。请帮帮我。