分类管理与标签管理

分类与标签

分类和标签是博客系统的两项功能。分类指用户定义类别并给博文归类。这是很自然地整理文章的方法，所以也成为博客系统的基本功能。后来，互联网上的文章又发展出一种方便友好的特色——标签（Label或Tag）。标签相当于传统文章的关键字和书本的索引，指明的是文章包含的某一点内容或者特色。分类往往是从某一个角度将所有文章讨论的范围分成几个子集。标签则只是反映文章的侧面和特色。两者相互补充，就像一本书既有目录也有索引。比如，我们可以把车辆分类为自行车、摩托车和汽车，同时又可以给不同的车贴上进口、永久牌、女式、我骑过的这些五花八门的标签。在一个网站上，如果标签设置得规整，保持一致的角度，也可以替代分类。用户操作上，类别需要单独先添加再选择，标签则可以即时输入或选择。互联网上灵活*的风格，两者若只选其一，标签比分类更适合。

Type

@OneToMany意即关联News表，返回某Type时也返回所有对应的News。

@Entity
@Table(name = "t_type")
public class Type {
    @Id  //主键标识
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    @NotBlank(message = "分类名称不能为空")
    private String name;

    @OneToMany(mappedBy = "type")
    private List<News> newsList = new ArrayList<>();

    public Type(){
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public List<News> getNewsList() {
        return newsList;
    }

    public void setNewsList(List<News> newsList) {
        this.newsList = newsList;
    }

    @Override
    public String toString() {
        return "Type{" +
                "id=" + id +
                ", name='" + name + '\'' +
                '}';
    }
}

@Service
public class TypeServiceImpl implements TypeService {
    @Autowired
    private TypeRepository typeRepository;
    @Override
    public Page<Type> listType(Pageable pageable) {
        return typeRepository.findAll(pageable);
    }

    @Override
    public Type saveType(Type type) {
        return typeRepository.save(type);
    }

    @Override
    public Type getTypeByName(String name) {
        return typeRepository.findByName(name);
    }

    @Override
    public void delete(Long id) {
        typeRepository.deleteById(id);
    }

    @Override
    public Type getType(Long id) {
        return typeRepository.findById(id).orElse(null);
    }

    @Override
    public Type updateType(Long id, Type type) {
        Type type1=typeRepository.findById(id).orElse(null);
        if(type1==null){
            return null;
        }
        BeanUtils.copyProperties(type,type1);
        return typeRepository.save(type1);
    }

    @Override
    public List<Type> listType() {
        return typeRepository.findAll();
    }
}

Spring Data JPA内置分页，用法是在参数中加入Pageable pageable，和参数注解@PageableDefault()

@Controller
@RequestMapping("/admin")
public class TypeController {
    @Autowired
    private TypeService typeService;

    @RequestMapping("/types")
    public String type(@PageableDefault(size = 3,sort = {"id"},direction = Sort.Direction.DESC)
                       Pageable pageable, Model model){
        model.addAttribute("page",typeService.listType(pageable));
       return "admin/types";
    }

    @GetMapping("/types/input")
    public String input(Model model){
        model.addAttribute("type",new Type());
        return "admin/types-input";
    }

    @PostMapping("/types/add")
    public String add(@Valid Type type, BindingResult result, RedirectAttributes attributes){
        Type type1=typeService.getTypeByName(type.getName());
        if(type1!=null){
            result.rejectValue("name","nameError","不能添加重复分类");
        }
        if(result.hasErrors()){
            return "admin/types-input";
        }
        Type type2=typeService.saveType(type);
        if(type2==null){
            attributes.addFlashAttribute("message","新增失败");
        }else{
            attributes.addFlashAttribute("message","新增成功");
        }
        return "redirect:/admin/types";
    }

    @RequestMapping("/types/{id}/delete")
    public String delete(@PathVariable long id,RedirectAttributes attributes){
        typeService.delete(id);
        attributes.addFlashAttribute("message","删除成功");
        return "redirect:/admin/types";
    }

    @RequestMapping("/types/{id}/toUpdate")
    public String toUpdate(@PathVariable Long id,Model model){
        model.addAttribute("type",typeService.getType(id));
        return "admin/types-input";
    }

    @RequestMapping("/types/update/{id}")
    public String update(@Valid Type type,BindingResult result,@PathVariable Long id,RedirectAttributes attributes) {
        Type type1 = typeService.getTypeByName(type.getName());
        if (type1 != null) {
            result.rejectValue("name", "nameError", "不能添加重复分类");
        }
        if (result.hasErrors()) {
            return "admin/types-input";
        }
        Type type2 = typeService.updateType(id, type);
        if (type2 != null) {
            attributes.addFlashAttribute("message", "更新成功");
        } else {
            attributes.addFlashAttribute("message", "更新失败");
        }
        return "redirect:/admin/types";
    }

}

Tag

@Entity
@Table(name="t_tag")
public class Tag {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    @NotBlank(message = "标求名不能为空")
    private String name;

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


    public Tag(){

    }

    public List<News> getNewsList() {
        return newsList;
    }

    public void setNewsList(List<News> newsList) {
        this.newsList = newsList;
    }

    public Long getId() {
        return id;
    }

    public void setId(Long id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    @Override
    public String toString() {
        return "Tag{" +
                "id=" + id +
                ", name='" + name + '\'' +
                '}';
    }
}

@Service
public class TagServiceimpl implements TagService {
    @Autowired
    private TagRepository tagRepository;
    @Override
    public Page<Tag> listTag(Pageable pageable) {
        return tagRepository.findAll(pageable);
    }

    @Override
    public Tag saveTag(Tag tag) {
        return tagRepository.save(tag);
    }

    @Override
    public void deleteTag(Long id) {
        tagRepository.deleteById(id);
    }

    @Override
    public Tag getTagByName(String name) {
        return tagRepository.findByName(name);
    }

    @Override
    public Tag getTag(Long id) {
        return tagRepository.findById(id).orElse(null);
    }

    @Override
    public Tag updateTag(Long id, Tag tag) {
        Tag tag1=tagRepository.findById(id).orElse(null);
        if(tag1==null){
            System.out.println("未获得更新对象");
            return null;
        }
        BeanUtils.copyProperties(tag,tag1);
        return tagRepository.save(tag1);

    }

    @Override
    public List<Tag> listTag() {
        return tagRepository.findAll();
    }

    @Override
    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;
    }
}

@Controller
@RequestMapping("/admin")
public class TagController {

    @Autowired
    private TagService tagService;

    @RequestMapping("/tags")
    private String tags(@PageableDefault(size=3,sort={"id"},direction = Sort.Direction.DESC)
                        Pageable pageable, Model model){
        model.addAttribute("page",tagService.listTag(pageable));
        return "admin/tags";
    }

    @GetMapping("/tags/input")
    public String input(Model model){
        model.addAttribute("tag",new Tag());
        return "admin/tags-input";
    }

    @PostMapping("/tags/add")
    public String add(@Valid Tag tag, BindingResult result, RedirectAttributes attributes){
        Tag tag1=tagService.getTagByName(tag.getName());
        if(tag1!=null){
            result.rejectValue("name","nameError","不能添加重复tag");
        }
        if(result.hasErrors()){
            return "admin/tags-input";
        }
        Tag type2=tagService.saveTag(tag);
        if(type2==null){
            attributes.addFlashAttribute("message","新增失败");
        }else{
            attributes.addFlashAttribute("message","新增成功");
        }
        return "redirect:/admin/tags";
    }

    @RequestMapping("/tags/{id}/toUpdate")
    public String toUpdate(@PathVariable Long id, Model model){
        model.addAttribute("tags",tagService.getTag(id));
        return "admin/tags-input";
    }

    @RequestMapping("/tags/update/{id}")
    public String update(@Valid Tag tag,BindingResult result,@PathVariable Long id,RedirectAttributes attributes) {
        Tag tag1 = tagService.getTagByName(tag.getName());
        if (tag1 != null) {
            result.rejectValue("name", "nameError", "不能添加重复tag");
        }
        if (result.hasErrors()) {
            return "admin/tags-input";
        }
        Tag tag2 = tagService.updateTag(id, tag);
        if (tag2 != null) {
            attributes.addFlashAttribute("message", "更新成功");
        } else {
            attributes.addFlashAttribute("message", "更新失败");
        }
        return "redirect:/admin/tags";
    }

}