新建实体

News.java:

@Entity
@Table(name = "t_news")
public class News {@Id  //主键标识@GeneratedValue(strategy = GenerationType.IDENTITY)private Long id;private String title;//懒加载@Basic(fetch = FetchType.LAZY)@Lobprivate String content;private String firstPicture;private String flag;private String views;private boolean appreciation;private boolean shareStatement;private boolean commentabled;private boolean published;private boolean recommend;@Temporal(TemporalType.TIMESTAMP)private Date createTime;@Temporal(TemporalType.TIMESTAMP)private Date updateTime;@ManyToOneprivate Type type;@ManyToOneprivate User user;@Transientprivate String tagIds;private String description;@ManyToMany(cascade = CascadeType.PERSIST)  //级联//tags名字要与Tag类中mapped by参数名相对应private List<Tag> tags = new ArrayList<>();public News(){}public void init(){this.tagIds =tagsToIds(this.getTags());}//将List<Tag>类型对象转化成"tagid1,tagid2,tagid3..."形式的String字符串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;}}//省略get和set方法
}

Tag.java:

@Entity
@Table(name = "t_tag")
public class Tag {@Id  //主键标识@GeneratedValue(strategy = GenerationType.IDENTITY)private Long id;@NotBlank(message = "标签名称不能为空")private String name;//mappedBy参数要与News类中List<Tag>变量名相对应@ManyToMany(mappedBy = "tags")private List<News> newsList = new ArrayList<>();public Tag(){}
}

Dao包新建接口

在dao包中涉及到的接口有如下两个：
NewRepository.java:

//NewRepository.java
public interface NewRepository extends JpaRepository<News,Long>, JpaSpecificationExecutor<News> {//只需要使用内置的方法即可
}

TagRepository.java:

//TagRepository.java
public interface TagRepository extends JpaRepository<Tag,Long> {Tag findByName(String name);
}

新建VO包

新建vo包，然后在其目录下新建NewQuery.java类，用来辅助对应News内容较为复杂的查询

//NewQuery.java
public class NewQuery {private String title;private Long typeId;private boolean recommend;public String getTitle() {return title;}public void setTitle(String title) {this.title = title;}public Long getTypeId() {return typeId;}public void setTypeId(Long typeId) {this.typeId = typeId;}public boolean isRecommend() {return recommend;}public void setRecommend(boolean recommend) {this.recommend = recommend;}@Overridepublic String toString() {return "NewQuery{" +"title='" + title + '\'' +", typeId=" + typeId +", recommend=" + recommend +'}';}
}

Service接口

在Service包中编写如下接口
NewService.java:

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

TagService.java:

//TagService.java
public interface TagService {Page<Tag> ListTag(Pageable pageable);Tag saveTag(Tag tag);void deleteTag(Long id);Tag getTagByName(String name);Tag getTag(Long id);Tag updateTag(Long id,Tag tag);List<Tag> listTag();List<Tag> listTag(String ids);
}

然后分别编写Impl类实现对应接口

NewServiceImpl.java：

//NewServiceImpl.java
@Service
public class NewServiceImpl implements NewService {@Autowiredprivate NewRepository newRepository;//新闻管理条件查询显示@Overridepublic Page<News> listNew(Pageable pageable, NewQuery newQuery) {return newRepository.findAll(new Specification<News>() {@Overridepublic Predicate toPredicate(Root<News> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) {List<Predicate> predicateList = new ArrayList<>();//是否存在标题检索if(!"".equals(newQuery.getTitle())&&newQuery.getTitle()!=null){predicateList.add(criteriaBuilder.like(root.<String>get("title"),"%"+newQuery.getTitle()+"%"));}//是否分类检索if(newQuery.getTypeId()!=null){predicateList.add(criteriaBuilder.equal(root.get("type").get("id"),newQuery.getTypeId()));}//是否推荐if(newQuery.isRecommend()){predicateList.add(criteriaBuilder.equal(root.get("recommend"),newQuery.isRecommend()));}criteriaQuery.where(predicateList.toArray(new Predicate[predicateList.size()]));return null;}}, (org.springframework.data.domain.Pageable) pageable);}@Overridepublic News saveNews(News news) {if(news.getId()==null){news.setCreateTime(new Date());news.setUpdateTime(new Date());}return newRepository.save(news);}@Overridepublic News getNew(Long id) {return newRepository.findById(id).orElse(null);}@Overridepublic News updateNew(News news) {News news1 = newRepository.findById(news.getId()).orElse(null);if(news1==null){System.out.println("未获取更新对象");}BeanUtils.copyProperties(news,news1);news1.setUpdateTime(new Date());return newRepository.save(news1);}
}

TagServiceImpl.java：

//TagServiceImpl.java
@Service
public class TagServiceImpl implements TagService {@Autowiredprivate TagRepository tagRepository;@Overridepublic Page<Tag> ListTag(Pageable pageable) {return tagRepository.findAll(pageable);}@Overridepublic Tag saveTag(Tag tag) {return tagRepository.save(tag);}@Overridepublic void deleteTag(Long id) {tagRepository.deleteById(id);}@Overridepublic Tag getTagByName(String name) {return tagRepository.findByName(name);}@Overridepublic Tag getTag(Long id) {return tagRepository.findById(id).orElse(null);}@Overridepublic 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;}else{BeanUtils.copyProperties(tag,tag1);return tagRepository.save(tag1);}}@Overridepublic List<Tag> listTag() {return tagRepository.findAll();}@Overridepublic List<Tag> listTag(String ids) {return tagRepository.findAllById(converToList(ids));}private List<Long> converToList(String ids){System.out.println("Service接受ids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]));}}return list;}
}

Web包

新建NewController.java类

@Controller
@RequestMapping("/admin")
public class NewController {private static final String INPUT = "admin/news-input";private static final String LIST = "admin/news";private static final String REDIRECT_LIST = "redirect:/admin/news";@Autowiredprivate NewService newService;@Autowiredprivate TypeService typeService;@Autowiredprivate TagService tagService;@RequestMapping("/news")public String news(@PageableDefault(size = 3,sort = {"updateTime"},direction = Sort.Direction.DESC)Pageable pageable, NewQuery newQuery, Model model){model.addAttribute("types",typeService.listType());model.addAttribute("page",newService.listNew(pageable,newQuery));return LIST;}@PostMapping("/news/search")public String search(@PageableDefault(size = 3,sort = {"updateTime"},direction = Sort.Direction.DESC)Pageable pageable, NewQuery newQuery, Model model){model.addAttribute("page",newService.listNew(pageable,newQuery));return "admin/news::newsList";}public void setTagAndType(Model model){model.addAttribute("types",typeService.listType());model.addAttribute("tags",tagService.listTag());}@GetMapping("/news/input")public String input(Model model){setTagAndType(model);model.addAttribute("news",new News());return INPUT;}@GetMapping("/news/{id}/toUpdate")public String toUpdate(@PathVariable Long id,Model model){setTagAndType(model);News news = newService.getNew(id);news.init();model.addAttribute("news",news);return INPUT;}@PostMapping("/news/add")public String post(News news, RedirectAttributes attributes, HttpSession session){news.setUser((User) session.getAttribute("user"));news.setType(typeService.getType(news.getType().getId()));news.setTags(tagService.listTag(news.getTagIds()));News news1;if(news.getId()==null){news1 = newService.saveNews(news);}else {news1 = newService.updateNew(news);}if(news1==null){attributes.addFlashAttribute("message","操作失败");}else{attributes.addFlashAttribute("message","操作成功");}return REDIRECT_LIST;}}

界面显示

新闻主界面：

新增界面：

发布成功：

通过分类搜索：

使用模糊搜索：

是否推荐搜索：

编辑界面：