jpa 的 Specification案例

dao接口除了extends JpaRepository外，还要 extends JpaSpecificationExecutor

        <dependency>
            <groupId>com.github.wenhao</groupId>
            <artifactId>jpa-spec</artifactId>
            <version>3.2.4</version>
        </dependency>

public interface UserDao extends JpaRepository<User, String>, JpaSpecificationExecutor<User> {

public Page<User> page(QueryVo queryVo){
        int page= paging.getPage();
        int size= paging.getSize();
 
        //写法一
        Specification<User> specification = (root, criteriaQuery, criteriaBuilder) -> {
            List<Predicate> predicateList = new ArrayList<>();
            if(queryVo.getName!= null && !"".equals(queryVo.getName.trim())){
                predicateList.add(criteriaBuilder.like(root.get("userName"), "%"+queryVo.getName+"%"));
            }
            predicateList.add(criteriaBuilder.equal(root.get("isDelete"), 0));
            return criteriaBuilder.and(predicateList.toArray(new Predicate[predicateList.size()]));
        };
 
        // 写法二
        Specification<User> specification2 = new Specification<PerfCase>() {
            @Override
            public Predicate toPredicate(Root<PerfCase> root, CriteriaQuery<?> query, CriteriaBuilder criteriaBuilder) { 
                List<Predicate> predicates = new ArrayList<>();
                if (queryVo.getName != null && !"".equals(queryVo.getName.trim())) {
                    predicates.add(criteriaBuilder.like(root.get("perfCaseName"), "%" + queryVo.getName + "%"));
                }
                predicates.add(criteriaBuilder.equal(root.get("isDelete"), 0));
                return criteriaBuilder.and(predicates.toArray(new Predicate[predicates.size()]));
            }
        };
        
 
        //排序
        Sort.Order order = new Sort.Order(Sort.Direction.DESC, "createTime");
        Sort sort = Sort.by(order);
 
       // 构造分页参数
        Pageable pageable = PageRequest.of(page-1, size, sort);
        Page<User> userPage = userDao.findAll(specification, pageable);
        return userPage;
    }
    
}