SpringBoot项目添加新闻管理的查询分页添加编辑功能

    @ManyToMany(cascade = CascadeType.PERSIST)//级联 多对多会生成中间表news-tas
    private List<Tag> tags=new ArrayList<>();
    @Transient
    private String tagIds;//不生成字段
    private String description;

    @ManyToMany(mappedBy = "tags")
    private List<News> newsList=new ArrayList<>();

    private String title;
    private Long typeId;
    private boolean recommend;

public interface NewService {
    Page<News> listNew(Pageable pageable, NewQuery newQuery);
    News saveNews(News news);
    News getNew(Long id);
    News updateNew(Long id, News news);
}

public interface NewRepository extends JpaRepository<News,Long>, JpaSpecificationExecutor<News> {
}

    //新闻管理中的列表(包含了查询)
    @Override
    public Page<News> listNew(Pageable pageable, NewQuery newQuery) {
        return newRepository.findAll(new Specification<News>() {
            @Override
            public Predicate toPredicate(Root<News> root, CriteriaQuery<?> cq, CriteriaBuilder cb) {
                List<Predicate> predicates=new ArrayList<>();
                if(!"".equals(newQuery.getTitle()) && newQuery.getTitle()!=null){
                    predicates.add(cb.like(root.<String>get("title"),"%"+newQuery.getTitle()+"%"));
                }
                if(newQuery.getTypeId()!=null){
                    predicates.add(cb.equal(root.get("type").get("id"),newQuery.getTypeId()));
                }
                if(newQuery.isRecommend()){
                    predicates.add(cb.equal(root.get("recommand"),newQuery.isRecommend()));
                }
                cq.where(predicates.toArray(new Predicate[predicates.size()]));
                return null;
            }
        },pageable);
    }

    @GetMapping("/news/{id}/toUpdate")
    public String toUpdate(@PathVariable Long id, Model model){
        setTypeAndTag(model);
        News news=newService.getNew(id);
        news.init();
        model.addAttribute("news",news);
        return INPUT;
    }

    public void init(){
        this.tagIds=tagsToIds(this.getTags());
    }
    private String tagsToIds(List<Tag> tags) {
        if(!tags.isEmpty()){
            StringBuffer ids= new StringBuffer();
            Boolean flag=false;
            for(Tag tag:tags){
                if(flag){
                    ids.append(",");}else{flag=true;}
                ids.append(tag.getId());}
            return ids.toString();}else{return tagIds;
        }
    }

    public List<Tag> listTag() {
        return tagRepository.findAll();
    }
    public List<Tag> listTag(String ids) {
        return tagRepository.findAllById(convertToList(ids));
    }
    private List<Long> convertToList(String ids){
        System.out.println("service接收TagId为"+ids);
        List<Long> list=new ArrayList<>();
        if(!"".equals(ids) && ids!=null){
            String[] idArray=ids.split(",");
            for(int i=0;i<idArray.length;i++){
                list.add(new Long(idArray[i]));
            }
        }
        System.out.println("service处理完后TagId为"+list);
        return list;
    }