SpringData JPA 实现动态条件查询

SpringData JPA 实现动态条件查询（包含分页、排序）

public interface UserRepository extends JpaRepository<User, Integer>,JpaSpecificationExecutor<User>{
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注意：

Page<T> findAll(Specification<T> spec, Pageable pageable);  //分页按条件查询List<T> findAll(Specification<T> spec);    //不分页按条件查询 

	public Page<User> getUserByIf(User user,Integer page,Integer size){return userRepository.findAll(new Specification<User>() {@Overridepublic Predicate toPredicate(Root<User> root, CriteriaQuery<?> query, CriteriaBuilder builder) {List<Predicate> predicates = new ArrayList<>();if(StringUtils.isNotBlank(user.getName())){predicates.add(builder.like(root.get("name"), "%"+user.getName()+"%")); like}if(user.getAge()!=null){predicates.add(builder.greaterThanOrEqualTo(root.get("age"), user.getAge()));//  >=}if(user.getId()!=null){predicates.add(builder.lessThanOrEqualTo(root.get("id"), user.getId()));//   <=}return builder.and(predicates.toArray(new Predicate[predicates.size()]));}}, new PageRequest(page, size, Direction.ASC, "id"));}