java开发语言代码实例

package com.zr0726.news.po;

import javax.persistence.*;
import java.util.ArrayList;
import java.util.Date;
import java.util.List;

@Entity
@Table(name = “t_news”)
public class News {

@Id
@GeneratedValue(strategy = GenerationType.IDENTITY)
private Long id;
private String title;
@Basic(fetch = FetchType.LAZY)
@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)
private Date createTime;
@Temporal(TemporalType.TIMESTAMP)
private Date updateTime;

@ManyToOne
private Type type;

@ManyToOne
private User user;

@ManyToMany(cascade = CascadeType.PERSIST)
private List<Tag> tags = new ArrayList<>();

@Transient
private String tagIds;

private String description;

public News(){
}

public Long getId() {
    return id;
}

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

public String getTitle() {
    return title;
}

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

public String getContent() {
    return content;
}

public void setContent(String content) {
    this.content = content;
}

public String getFirstPicture() {
    return firstPicture;
}

public void setFirstPicture(String firstPicture) {
    this.firstPicture = firstPicture;
}

public String getFlag() {
    return flag;
}

public void setFlag(String flag) {
    this.flag = flag;
}

public String getViews() {
    return views;
}

public void setViews(String views) {
    this.views = views;
}

public boolean isAppreciation() {
    return appreciation;
}

public void setAppreciation(boolean appreciation) {
    this.appreciation = appreciation;
}

public boolean isShareStatement() {
    return shareStatement;
}

public void setShareStatement(boolean shareStatement) {
    this.shareStatement = shareStatement;
}

public boolean isCommentabled() {
    return commentabled;
}

public void setCommentabled(boolean commentabled) {
    this.commentabled = commentabled;
}

public boolean isPublished() {
    return published;
}

public void setPublished(boolean published) {
    this.published = published;
}

public boolean isRecommend() {
    return recommend;
}

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

public Date getCreateTime() {
    return createTime;
}

public void setCreateTime(Date createTime) {
    this.createTime = createTime;
}

public Date getUpdateTime() {
    return updateTime;
}

public void setUpdateTime(Date updateTime) {
    this.updateTime = updateTime;
}

public Type getType() {
    return type;
}

public void setType(Type type) {
    this.type = type;
}

public User getUser() {
    return user;
}

public void setUser(User user) {
    this.user = user;
}

public List<Tag> getTags() {
    return tags;
}

public void setTags(List<Tag> tags) {
    this.tags = tags;
}

public String getTagIds() {
    return tagIds;
}

public void setTagIds(String tagId) {
    this.tagIds = tagIds;
}

public String getDescription() {
    return description;
}

public void setDescription(String description) {
    this.description = description;
}

public void init(){
    this.tagIds = tagsToIds(this.getTags());
}

//1,2,3
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;
    }
}

@Override
public String toString() {
    return "News{" +
            "id=" + id +
            ", title='" + title + '\'' +
            ", content='" + content + '\'' +
            ", firstPicture='" + firstPicture + '\'' +
            ", flag='" + flag + '\'' +
            ", views='" + views + '\'' +
            ", appreciation=" + appreciation +
            ", shareStatement=" + shareStatement +
            ", commentabled=" + commentabled +
            ", published=" + published +
            ", recommend=" + recommend +
            ", createTime=" + createTime +
            ", updateTime=" + updateTime +
            ", type=" + type +
            ", user=" + user +
            ", tags=" + tags +
            ", tagIds='" + tagIds + '\'' +
            ", description='" + description + '\'' +
            '}';
} 

}

package com.zr0726.news.service.impl;

import com.zr0726.news.dao.NewRepository;
import com.zr0726.news.po.News;
import com.zr0726.news.service.NewService;
import com.zr0726.news.vo.NewQuery;
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 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 NewServiceImpl implements NewService {

@Autowired
private NewRepository newRepository;

//新闻管理中的新闻列表（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("recommend"),newQuery.isRecommend()));
            }
            cq.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);
} 

}

本文地址：https://blog.csdn.net/KanaseKanon/article/details/107888889