springboot实现新闻管理功能
接着昨天的项目继续开发：
新闻实体类：
@Entity
@Table(name = "t_news")
public class News {
@Id //主键标识
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String title;
@Basic(fetch = FetchType.LAZY) //懒加载
@Lob
private 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) //年月日-时分秒
private Date createTime;
@Temporal(TemporalType.TIMESTAMP)
private Date updateTime;
@ManyToOne
private Type type;
@ManyToOne
private User user;
@ManyToMany(cascade = CascadeType.PERSIST) //级联
private List<Tag> tags=new ArrayList<>();
@Transient //该注解表示不会被映射到数据库中
private String tagIds;//接收前端页面传过来的标签Id
private String description;
}
创建vo包，VO是指value object值对象，通常用于业务层之间的数据传递，和PO一样也是仅仅包含数据而已。一般来说，PO只能用在数据层，VO用在商业逻辑层和表示层。在vo包下创建NewsQuery类，我们利用NewsQuery类专门处理新闻管理界面的条件查询。因为我们需要通过新闻的标题、类型以及是否被推荐作为条件来查询数据库里的新闻，所以我们就利用这三个属性来组成一个查询类。
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;
}
@Override
public String toString() {
return "NewQuery{" +
"title='" + title + '\'' +
", typeId=" + typeId +
", recommend=" + recommend +
'}';
}
}
之后同样的，写对应的service和Impl：
@Service
public class NewServiceImpl implements NewService {
@Autowired
private NewRepository newRepository;
//新闻管理中的列表（包括了查询）
@Override
public Page<News> listNew(Pageable pageable, NewQuery newQuery) {
return newRepository.findAll(new Specification<News>() {
@Override
public Predicate toPredicate(Root<News> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) {
List<Predicate> predicates=new ArrayList<>();
if(!"".equals(newQuery.getTitle())&&newQuery.getTitle()!=null){
predicates.add(criteriaBuilder.like(root.<String>get("title"),"%"+newQuery.getTitle()+"%"));
}
if(newQuery.getTypeId()!=null){
predicates.add(criteriaBuilder.equal(root.get("type").get("id"),newQuery.getTypeId()));
}
if(newQuery.isRecommend()){
predicates.add(criteriaBuilder.equal(root.get("recommend"),newQuery.isRecommend()));
}
criteriaQuery.where(predicates.toArray(new Predicate[predicates.size()]));
return null;
}
},pageable);
}
@Override
public News saveNew(News news) {
if(news.getId()==null){
news.setCreateTime(new Date());
news.setUpdateTime(new Date());
}
return newRepository.save(news);
}
@Override
public News getNew(Long id) {
return newRepository.findById(id).orElse(null);
}
@Override
public News updateNew(Long id, News news) {
News news1=newRepository.findById(id).orElse(null);
if(news1==null){
System.out.println("未获得更新对象");
}
BeanUtils.copyProperties(news,news1);
news1.setUpdateTime(new Date());
return newRepository.save(news1);
}
}
最后编写controller，实现对应的管理功能即可：
@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";
@Autowired
private NewService newService;
@Autowired
private TypeService typeService;
@Autowired
private TagService tagService;
@GetMapping("/news")
public String news(@PageableDefault(size=5,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=5,sort={
"updateTime"},direction = Sort.Direction.DESC)
Pageable pageable, NewQuery newQuery, Model model){
model.addAttribute("page",newService.listNew(pageable,newQuery));
return "admin/news::newsList";//指定页面中的newsList的片段
}
public void setTypeAndTag(Model model){
model.addAttribute("types",typeService.listType());
model.addAttribute("tags",tagService.listTag());
}
@GetMapping("/news/input")
public String input(Model model){
setTypeAndTag(model);
model.addAttribute("news",new News());
return INPUT;
}
@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;
}
@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.saveNew(news);
}else {
news1=newService.updateNew(news.getId(), news);
}
if(news1==null){
attributes.addFlashAttribute("message","操作失败");
}else{
attributes.addFlashAttribute("message","操作成功");
}
return REDIRECT_LIST;
}
}
最后看看结果：
进入新闻界面
点击新增，编写一条新闻：
可以看到可以对新闻设置响应的分类和tag，都是我们之前写好的
