一、列表查询示例

        WhereBuilder<OrderEntity> builder = new WhereBuilder<>();

        Specification<OrderEntity> specification = (Specification<OrderEntity>) (root, query, criteriaBuilder) -> {
            List<Predicate> predicate = new ArrayList<>();
            //相等
            predicate.add(criteriaBuilder.equal(root.get("userId"), model.getUserId()));

            Predicate predicateAnd = criteriaBuilder.and(predicate.toArray(new Predicate[predicate.size()]));
            return query.where(predicateAnd).orderBy(criteriaBuilder.desc(root.get("createTime"))).getRestriction();
        };
        Pageable pageable = builder.getPageable(model.getPage() != null ? model.getPage() : 0, model.getSize() != null ? model.getSize() : 20);
        Page<OrderEntity> all = orderDao.findAll(specification, pageable);
        return new PageImpl<>(all.getContent(), all.getPageable(), all.getTotalElements());

二、其他

模糊查询

            predicate.add(criteriaBuilder.like(root.get("userName"), "%" + model.getUserName() + "%"));

相等

            predicate.add(criteriaBuilder.equal(root.get("userId"), model.getUserId()));

in查询

            List<String> pointIds = new ArrayList<>();
            CriteriaBuilder.In<String> in = criteriaBuilder.in(root.get("pointId"));
            pointIds.forEach(in::value);
            predicate.add(in);

大于（int）

            predicate.add(criteriaBuilder.gt(root.get("number"), model.getNumber()));

大于（LocalDateTime）

             predicate.add(criteriaBuilder.greaterThan(root.get("createTime"), createTime));

or

//where
Specification<OrderEntity> specification = (Specification<OrderEntity>) (root, query, criteriaBuilder) -> {
    //and
    List<Predicate> predicates = new ArrayList<>();
    predicates.add(criteriaBuilder.equal(root.get("userId"), "123456"));
    if (model != null && model.getStateFrontend() != null) {
        predicates.add(criteriaBuilder.equal(root.get("stateFrontend"), model.getStateFrontend()));
    }

    //or
    List<Predicate> predicateOrs = new ArrayList<>();
    if (model != null && StringUtil.isNotNullEmpty(model.getKeyWord())) {
        predicateOrs.add(criteriaBuilder.like(root.get("spaceGroupNameTop"), "%" + model.getKeyWord() + "%"));
        predicateOrs.add(criteriaBuilder.like(root.get("pointName"), "%" + model.getKeyWord() + "%"));
    }

    Predicate predicateOr = criteriaBuilder.or(predicateOrs.toArray(new Predicate[predicateOrs.size()]));
    predicates.add(predicateOr);

    return criteriaBuilder.and(predicates.toArray(new Predicate[predicates.size()]));
};

假list

WhereBuilder<MeetingEntity> builder = new WhereBuilder<>();
Pageable pageable = builder.getPageable(model.getPage() != null ? model.getPage() : 0, model.getSize() != null ? model.getSize() : 20);

List<MeetingFindAllVm> result = new ArrayList<>();
MeetingFindAllVm result1 = new MeetingFindAllVm();
result.add(result1);
return new PageImpl<>(result, pageable, 1);