实现评论+分类页+标签页功能

实现评论+分类页+标签页功能

1.评论

首先新增实体类Comment：

package com.zr0726.news.po;


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

@Entity
@Table(name="t_comment")
public class Comment {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String nickname;
    private String email;
    private String content;
    private String avatar;
    @Temporal(TemporalType.TIMESTAMP)
    private Date createTime;

    @ManyToOne
    private News news;

    @OneToMany(mappedBy = "parentComment")
    private List<Comment> replyComments=new ArrayList<>();

    @ManyToOne
    private Comment parentComment;

    private boolean adminComment;

    public Comment() {
    }

    public Long getId() {
        return id;
    }

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

    public String getNickname() {
        return nickname;
    }

    public void setNickname(String nickname) {
        this.nickname = nickname;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getContent() {
        return content;
    }

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

    public String getAvatar() {
        return avatar;
    }

    public void setAvatar(String avatar) {
        this.avatar = avatar;
    }

    public Date getCreateTime() {
        return createTime;
    }

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

    public News getNews() {
        return news;
    }

    public void setNews(News news) {
        this.news = news;
    }

    public List<Comment> getReplyComments() {
        return replyComments;
    }

    public void setReplyComments(List<Comment> replyComments) {
        this.replyComments = replyComments;
    }

    public Comment getParentComment() {
        return parentComment;
    }

    public void setParentComment(Comment parentComment) {
        this.parentComment = parentComment;
    }

    public boolean isAdminComment() {
        return adminComment;
    }

    public void setAdminComment(boolean adminComment) {
        this.adminComment = adminComment;
    }

    @Override
    public String toString() {
        return "Comment{" +
                "id=" + id +
                ", nickname='" + nickname + '\'' +
                ", email='" + email + '\'' +
                ", content='" + content + '\'' +
                ", avatar='" + avatar + '\'' +
                ", createTime=" + createTime +
                ", news=" + news +
                ", replyComments=" + replyComments +
                ", parentComment=" + parentComment +
                ", adminComment=" + adminComment +
                '}';
    }
}

然后在News实体类中增加评论与新闻的对应关系（getter和setter方法也要添加）：

@OneToMany(mappedBy = "news")
    private List<Comment> comments=new ArrayList<>();


	public List<Comment> getComments() {
        return comments;
    }

    public void setComments(List<Comment> comments) {
        this.comments = comments;
    }

在service层新建CommentService接口：

package com.zr0726.news.service;

import com.zr0726.news.po.Comment;

import java.util.List;

public interface CommentService {

    List<Comment> listCommentByNewId(Long newId);
    Comment saveComment(Comment comment);

}

在CommentServiceImpl中实现接口的方法：

package com.zr0726.news.service.impl;

import com.sun.org.apache.regexp.internal.RE;
import com.zr0726.news.dao.CommentRepository;
import com.zr0726.news.po.Comment;
import com.zr0726.news.service.CommentService;
import org.springframework.beans.BeanUtils;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.data.domain.Sort;
import org.springframework.stereotype.Service;

import java.util.ArrayList;
import java.util.Date;
import java.util.List;

@Service
public class CommentServiceImpl implements CommentService {

    @Autowired
    private CommentRepository commentRepository;

    @Override
    public List<Comment> listCommentByNewId(Long newId) {

        Sort sort= Sort.by("createTime");
        List<Comment> comments=commentRepository.findByNewsIdAndParentCommentNull(newId,sort);
        return eachComment(comments);
    }


    private  List<Comment> eachComment(List<Comment> comments){
        List<Comment> commentsView =new ArrayList<>();
        for(Comment comment:comments){
            Comment c=new Comment();
            BeanUtils.copyProperties(comment,c);
            commentsView.add(c);
        }
        //合并评论的各层子代到第一级子代集合中
        combineChildren(commentsView);
        return commentsView;
    }

    private void combineChildren(List<Comment> comments){
        for(Comment comment:comments){
            List<Comment> replys1=comment.getReplyComments();
            for (Comment reply1:replys1){
                //循环迭代，找出子代,存放在临时tempReplys中
                recursively(reply1);
            }
            comment.setReplyComments(tempReplys);
            //清除临时存放区，再新建一个新的临时存放区
            tempReplys=new ArrayList<>();
        }
    }

    private List<Comment> tempReplys=new ArrayList<>();

    private void recursively(Comment comment){
        tempReplys.add(comment);//顶节点添加到临时存放区
        if(comment.getReplyComments().size()>0){
            List<Comment> replys= comment.getReplyComments();
            for (Comment reply:replys){
                tempReplys.add(reply);
                if(reply.getReplyComments().size()>0){
                    recursively(reply);
                }
            }
        }
    }

    @Override
    public Comment saveComment(Comment comment) {

            Long pareCommentId = comment.getParentComment().getId();
            if(pareCommentId!=-1){
                comment.setParentComment(commentRepository.findById(pareCommentId).orElse(null));
            }else {
                comment.setParentComment(null);
            }
            comment.setCreateTime(new Date());

            return commentRepository.save(comment);
    }


}

在CommentController中编写相关的操作：

package com.zr0726.news.web;

import com.zr0726.news.po.Comment;
import com.zr0726.news.po.User;
import com.zr0726.news.service.CommentService;
import com.zr0726.news.service.NewService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.PostMapping;

import javax.servlet.http.HttpSession;

@Controller
public class CommentController {

    @Autowired
    private CommentService commentService;

    @Autowired
    private NewService newService;

    private String avatar="http://pic.netbian.com/uploads/allimg/170609/123945-1496983185ad61.jpg";


    @GetMapping("/comments/{newId}")
    public String comments(@PathVariable Long newId, Model model){
        model.addAttribute("comments",commentService.listCommentByNewId(newId));
        return "new::commentList";
    }

    @PostMapping("/comments")
    public String post(Comment comment, HttpSession session){
        Long newId=comment.getNews().getId();
        comment.setNews(newService.getNew(newId));
        User user=(User) session.getAttribute("user");
        if(user!=null){
            comment.setAdminComment(true);
            comment.setAvatar(avatar);
        }else {
            comment.setAvatar(avatar);
        }
        commentService.saveComment(comment);
//        System.out.println("$$##@@#$$#@@##"+commentService.saveComment(comment));
        return "redirect:/comments/"+newId;
    }

}

运行项目：
首先要在新闻管理页中确保该篇新闻的评论权限是打开的:

如果权限没打开，点击新闻是看不到评论界面的：

点击一篇开启了评论权限的新闻，可以看到评论页面和发布评论页面：

增加一条评论：

回复一条评论：

2.分类页面：

新建TypeShowController：

package com.zr0726.news.web;


import com.zr0726.news.po.Type;
import com.zr0726.news.service.NewService;
import com.zr0726.news.service.TypeService;
import com.zr0726.news.vo.NewQuery;
import org.springframework.beans.factory.annotation.Autowired;
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.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;

import java.util.List;

@Controller
public class TypeShowController {
    @Autowired
    private TypeService typeService;

    @Autowired
    private NewService newService;

    @GetMapping("/types/{id}")
    public String types(@PageableDefault(size = 8,sort = {"updateTime"},direction = Sort.Direction.DESC) Pageable pageable,
                        @PathVariable Long id, Model model){
        List<Type> types = typeService.listTypeTop(20);
        if (id==-1){
            id = types.get(0).getId();
        }
        NewQuery newQuery = new NewQuery();
        newQuery.setTypeId(id);
        model.addAttribute("types",types);
        model.addAttribute("page",newService.listNew(pageable,newQuery));
        model.addAttribute("activeTypeId",id);
        return "types";
    }
}

运行项目：
点击分类，进入分类页面：

点击计算机分类，就展示了计算机分类的新闻：

3.标签页面

在NewService中增加接口：

//标签页面查看新闻
    Page<News> listNew(Long tagId,Pageable pageable);

在NewServiceImpl中实现接口：

    @Override
    public Page<News> listNew(Long tagId, Pageable pageable) {

        return newRepository.findAll(new Specification<News>() {
            @Override
            public Predicate toPredicate(Root<News> root, CriteriaQuery<?> cq, CriteriaBuilder cb) {
                Join join=root.join("tags");
                return cb.equal(join.get("id"),tagId);
            }
        },pageable);
    }

新增TagShowController：

package com.zr0726.news.web;

import com.zr0726.news.po.Tag;
import com.zr0726.news.service.NewService;
import com.zr0726.news.service.TagService;
import com.zr0726.news.vo.NewQuery;
import org.springframework.beans.factory.annotation.Autowired;
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.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;

import java.util.List;

@Controller
public class TagShowController {

    @Autowired
    private NewService newService;

    @Autowired
    private TagService tagService;

    @GetMapping("/tags/{id}")
    public String tags(@PageableDefault(size = 8,sort = {"updateTime"},direction = Sort.Direction.DESC)
                               Pageable pageable, @PathVariable Long id, Model model){
        List<Tag> tags = tagService.listTagTop(20);
        if (id==-1){
            id = tags.get(0).getId();
        }
//        NewQuery newQuery = new NewQuery();
//        newQuery.setTagId(id);
        model.addAttribute("tags",tags);
        model.addAttribute("page",newService.listNew(id,pageable));
        model.addAttribute("activeTagId",id);
        return "tags";
    }
}

运行项目：
点击标签，转到标签界面：

选择点击Dota标签，显示Dota标签的新闻：