7.29第九次实训笔记

实训感受

1、今天实现了新闻的新增，编辑。感觉有点难的，可能是刚接触，感觉很陌生，但也是挺实用的。
2、尤其是在写搜索的时候，感觉很迷，但学会了以后在其他场景都可以用得上。

课堂项目编码

controller层

package com.zr.controller;

import com.zr.po.*;
import com.zr.service.NewsService;
import com.zr.service.TagService;
import com.zr.service.TypeService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.domain.Sort;
import org.springframework.data.web.PageableDefault;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RequestMapping;

import javax.servlet.http.HttpSession;
import java.util.List;

@Controller
@RequestMapping("/admin/news")
public class NewsController {
    @Autowired
    private NewsService newsService;

    @Autowired
    private TypeService typeService;

    @Autowired
    private TagService tagService;

    @RequestMapping
    public String list(@PageableDefault(size = 5,sort={"updateTime"},direction = Sort.Direction.DESC)Pageable pageable, Model model){
        Page<News> page=newsService.findByPageable(pageable);
        model.addAttribute("page",page);
        model.addAttribute("types",typeService.listType());
        return "admin/news";
    }

    @RequestMapping("input/{id}")
    public String toInput(@PathVariable Long id,Model model){
        if(id==-1){
            model.addAttribute("news",new News());
        }else{
            News news=newsService.findNewsById(id);
            String tagIds=tagService.getTagIds(news.getTags());
            news.setTagIds(tagIds);
            model.addAttribute("news",news);
        }
        List<Type> types=typeService.listType();
        model.addAttribute("types",types);
        model.addAttribute("tags",tagService.listTag());
        return "admin/news-input";
    }

    @RequestMapping("input")
    public String input(News news, HttpSession session){
        User user=(User)session.getAttribute("user");
        news.setUser(user);
        List<Tag>tags=tagService.findTagByTagId(news.getTagIds());
        news.setTags(tags);
        newsService.input(news);
        return "redirect:/admin/news";
    }

    @RequestMapping("search")
    public String search(@PageableDefault(size = 5,sort={"updateTime"},direction = Sort.Direction.DESC)Pageable pageable, Model model,
                         NewsQuery newsQuery){
        Page<News> page=newsService.searchNews(pageable,newsQuery);
        model.addAttribute("page",page);
        return "admin/news :: newsList";
    }
}

dao层

package com.zr.dao;

import com.zr.po.News;
import org.springframework.data.jpa.repository.JpaRepository;
import org.springframework.data.jpa.repository.JpaSpecificationExecutor;

public interface NewsDao extends JpaRepository<News,Long> , JpaSpecificationExecutor<News> {


}

po层

package com.zr.po;

public class NewsQuery {
    private String title;
    private String typeId;
    private Boolean recommend;

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getTypeId() {
        return typeId;
    }

    public void setTypeId(String typeId) {
        this.typeId = typeId;
    }

    public Boolean getRecommend() {
        return recommend;
    }

    public void setRecommend(Boolean recommend) {
        this.recommend = recommend;
    }

    public NewsQuery() {
    }

    public NewsQuery(String title, String typeId, Boolean recommend) {
        this.title = title;
        this.typeId = typeId;
        this.recommend = recommend;
    }

    @Override
    public String toString() {
        return "NewsQuery{" +
                "title='" + title + '\'' +
                ", typeId='" + typeId + '\'' +
                ", recommend=" + recommend +
                '}';
    }
}

service层
接口：

package com.zr.service;

import com.zr.po.News;
import com.zr.po.NewsQuery;
import com.zr.po.Tag;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;

import java.util.List;

public interface NewsService {
    Page<News> findByPageable(Pageable pageable);

    void input(News news);

    News findNewsById(Long id);


    Page<News> searchNews(Pageable pageable, NewsQuery newsQuery);
}

实现层

package com.zr.service.Impl;

import com.zr.dao.NewsDao;
import com.zr.po.News;
import com.zr.po.NewsQuery;
import com.zr.po.Tag;
import com.zr.po.Type;
import com.zr.service.NewsService;
import com.zr.util.MyBeanUtils;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Page;
import org.springframework.data.domain.Pageable;
import org.springframework.data.jpa.domain.Specification;
import org.springframework.stereotype.Service;
import org.springframework.util.StringUtils;

import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Predicate;
import javax.persistence.criteria.Root;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

@Service
public class NewsServiceImpl implements NewsService {
    @Autowired
    private NewsDao newsDao;

    public Page<News> findByPageable(Pageable pageable) {
        return newsDao.findAll(pageable);
    }

    public void input(News news) {
        if(news.getId()==null){
            news.setCreateTime(new Date());
            newsDao.save(news);
        }else{
            news.setUpdateTime(new Date());
            News n=newsDao.getOne(news.getId());
            BeanUtils.copyProperties(news,n, MyBeanUtils.getNullPropertyNames(news));
            newsDao.save(n);
        }


    }

    public News findNewsById(Long id) {
        return newsDao.getOne(id);
    }

    public Page<News> searchNews(Pageable pageable, final NewsQuery newsQuery) {
        Page<News> news=newsDao.findAll(new Specification<News>(){
            public Predicate toPredicate(Root<News> root, CriteriaQuery<?> criteriaQuery, CriteriaBuilder criteriaBuilder) {
                List<Predicate> predicates = new ArrayList<>();
                if(!StringUtils.isEmpty(newsQuery.getTitle())){
                    predicates.add(criteriaBuilder.like(root.<String>get("title"),"%"+newsQuery.getTitle()+"%"));
                }
                if(!StringUtils.isEmpty(newsQuery.getTypeId())){
                    predicates.add(criteriaBuilder.equal(root.<Type>get("type").get("id"),newsQuery.getTypeId()));
                }
                if(newsQuery.getRecommend()!=null){
                    predicates.add(criteriaBuilder.equal(root.<Boolean>get("recommend"),newsQuery.getRecommend()));
                }
                criteriaQuery.where(predicates.toArray(new Predicate[predicates.size()]));
                return null;


            }
        },pageable);
        return news;
    }


}

课堂项目成果展示

新增（界面缩小了50%）

新闻界面

搜索功能

本文地址：https://blog.csdn.net/weixin_44043727/article/details/107678062