牛客网项目---2.3.查看帖子详情以及显示评论

帖子详情

在帖子标题上增加访问帖子的链接

4、帖子详情/detail/{discussPostId}：在帖子标题处，添加href标签，进入帖子详情，restful风格，后台可以根据@PathVariable("discussPostId")直接获取帖子id，进行查询，加到model中，返回帖子页面

5、版主可设置置顶加精

6、管理员可以进行删除和统计日活

7、使用卡夫卡进行系统通知

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1.CommentMapper：

import com.nowcoder.community.entity.Comment;
import org.springframework.stereotype.Repository;
 
import java.util.List;
 
@Repository
public interface CommentMapper {
    List selectCommentByEntity(int entityType,int entityId,int offset,int limit);
 
    int selectCountByEntity(int entityType,int entityId);
 
    int insertComment(Comment comment);
}

2.编写CommentMapper.xml：

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.nowcoder.community.mapper.CommentMapper">
    <select id="selectCommentByEntity" resultType="comment">
        select * from comment where status=0 and entity_type=#{entityType} and entity_id=#{entityId} order by create_time asc limit #{offset},#{limit};
    </select>
 
    <select id="selectCountByEntity" resultType="int">
        select count(id) from comment where status=0 and entity_type=#{entityType} and entity_id=#{entityId};
    </select>
 
    <insert id="insertComment" keyProperty="id" parameterType="Comment">
        insert into comment(user_id, entity_type, entity_id, target_id, content, status, create_time) VALUES (#{userId},#{entityType},#{entityId},#{targetId},#{content},#{status},#{createTime});
    </insert>
</mapper>

3.CommentService：

import com.nowcoder.community.entity.Comment;
import com.nowcoder.community.mapper.CommentMapper;
import com.nowcoder.community.util.CommunityConstant;
import com.nowcoder.community.util.SensitiveFilter;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Isolation;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.web.util.HtmlUtils;
 
import java.util.List;
 
@Service
public class CommentServiceImpl implements CommentService, CommunityConstant {
 
    @Autowired
    private CommentMapper commentMapper;
 
    @Autowired
    private SensitiveFilter sensitiveFilter;
 
    @Autowired
    private DiscussPostServiceImpl discussPostService;
 
    @Override
    public List selectCommentByEntity(int entityType, int entityId, int offset, int limit) {
        return commentMapper.selectCommentByEntity(entityType, entityId, offset, limit);
    }
 
    @Override
    public int selectCountByEntity(int entityType, int entityId) {
        return commentMapper.selectCountByEntity(entityType, entityId);
    }
 
    @Override
    public int insertComment(Comment comment) {
        return commentMapper.insertComment(comment);
    }

4.DiscussPostController：

import com.nowcoder.community.entity.Comment;
import com.nowcoder.community.entity.DiscussPost;
import com.nowcoder.community.entity.Page;
import com.nowcoder.community.entity.User;
import com.nowcoder.community.service.CommentServiceImpl;
import com.nowcoder.community.service.DiscussPostServiceImpl;
import com.nowcoder.community.service.UserServiceImpl;
import com.nowcoder.community.util.CommunityConstant;
import com.nowcoder.community.util.CommunityUtil;
import com.nowcoder.community.util.HostHolder;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.*;
 
import java.util.*;
 
@Controller
@RequestMapping("/discuss")
public class DiscussPostController implements CommunityConstant {
    @Autowired
    private DiscussPostServiceImpl discussPostService;
 
    @Autowired
    private HostHolder hostHolder;
 
    @Autowired
    private UserServiceImpl userService;
 
    @Autowired
    private CommentServiceImpl commentService;
 
    @PostMapping("/add")
    @ResponseBody
    public String addDiscussPost(String title,String content){
        User user = hostHolder.getUser();
        if (user==null){
            return CommunityUtil.getJSONString(403,"你还没有登陆");
        }
 
        DiscussPost discussPost = new DiscussPost();
        discussPost.setUserId(user.getId());
        discussPost.setTitle(title);
        discussPost.setContent(content);
        discussPost.setCreateTime(new Date());
 
        discussPostService.addDiscussPost(discussPost);
 
        return CommunityUtil.getJSONString(0,"发布成功");
    }
 
    @GetMapping("/detail/{discussPostId}")
    public String getDiscussPost(@PathVariable("discussPostId") int discussPostId, Model model, Page page){
        //帖子
        DiscussPost post = discussPostService.selectDiscussPostById(discussPostId);
        model.addAttribute("post",post);
 
        //作者
        User user = userService.selectById(post.getUserId());
        model.addAttribute("user",user);
 
        //评论分页信息
        page.setPath("/discuss/detail/"+discussPostId);
        page.setLimit(5);
        page.setRows(post.getCommentCount());
 
        //评论：给帖子的评论
        //回复：给评论的评论
 
        //评论列表
        List commentList = commentService.selectCommentByEntity(ENTITY_TYPE_POST, post.getId(), page.getOffset(), page.getLimit());
        //评论VO列表
        List<Map<String,Object>> commentVoList=new ArrayList<>();
        if (commentList!=null){
            for (Comment comment : commentList) {
                //评论VO
                Map commentVo=new HashMap<>();
                //评论
                commentVo.put("comment",comment);
                //作者
                commentVo.put("user",userService.selectById(comment.getUserId()));
 
                //回复列表
                List replayList = commentService.selectCommentByEntity(ENTITY_TYPE_COMMENT, comment.getId(), 0, Integer.MAX_VALUE);
                //回复VO列表
                List<Map<String,Object>> replayVoList=new ArrayList<>();
                if (replayList!=null){
                    for (Comment replay : replayList) {
                        Map replayVo=new HashMap<>();
                        //回复
                        replayVo.put("replay",replay);
                        //作者
                        replayVo.put("user",userService.selectById(replay.getUserId()));
                        //回复目标
                        User target=replay.getTargetId()==0?null:userService.selectById(replay.getTargetId());
                        replayVo.put("target",target);
 
                        replayVoList.add(replayVo);
                    }
                }
                commentVo.put("replays",replayVoList);
 
                //回复数量
                int replayCount = commentService.selectCountByEntity(ENTITY_TYPE_COMMENT, comment.getId());
                commentVo.put("replayCount",replayCount);
 
                commentVoList.add(commentVo);
            }
        }
        model.addAttribute("comments",commentVoList);
 
        return "/site/discuss-detail";
    }
}