6_1_评论中心

一 需求描述

1. 当分享发布一条头条消息后，当前用户可在指定消息内评论头条；

2. 评论完成后能够在当前页面显示以及评论数的改变

效果描述：

二 具体实现

1. DB

DROP TABLE IF EXISTS `comment`;
CREATE TABLE `comment`(
  `id` int NOT NULL AUTO_INCREMENT,
  `content`  TEXT NOT NULL comment ‘评论内容‘,
  `entity_id` INT NOT NULL comment ‘实体id‘,
  `entity_type` INT NOT NULL comment ‘实体类型‘,
  `created_date` DATETIME NOT NULL comment ‘创建日期‘,
  `user_id` INT NOT NULL comment ‘评论用户id‘,
  `status` INT NOT NULL DEFAULT 0 comment ‘评论会话状态‘,
  PRIMARY KEY(`id`),
  INDEX `entity_index `(`entity_id` ASC ,`entity_type` ASC )

) ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT=‘评论中心‘;

2. Model

package com.nowcoder.model;

import org.springframework.stereotype.Component;

import java.util.Date;

/**
 * Created by Administrator on 2017/4/29.
 */
@Component
public class Comment {

    private int id;
    private String content;
    private int entityId;
    private int entityType;
    private Date createdDate;
    private int userId;
    private int status;

    public int getId() {
        return id;
    }

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

    public String getContent() {
        return content;
    }

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

    public int getEntityId() {
        return entityId;
    }

    public void setEntityId(int entityId) {
        this.entityId = entityId;
    }

    public int getEntityType() {
        return entityType;
    }

    public void setEntityType(int entityType) {
        this.entityType = entityType;
    }

    public Date getCreatedDate() {
        return createdDate;
    }

    public void setCreatedDate(Date createdDate) {
        this.createdDate = createdDate;
    }

    public int getUserId() {
        return userId;
    }

    public void setUserId(int userId) {
        this.userId = userId;
    }

    public int getStatus() {
        return status;
    }

    public void setStatus(int status) {
        this.status = status;
    }
}

3. Dao:

int addCommnet(Comment comment); 添加评论
 List<Comment> selectByEntity(@Param("entityId") int entityId, @Param("entityType") int entityType);  ：  根据entityId查询所有评论；
 int getCommentCount(@Param("entityId") int entityId, @Param("entityType") int entityType);   ：  获取所有评论数量
void updateStatus(@Param("entityId") int entityId,
                      @Param("entityType") int entityType,
                      @Param("status") int status);  删除评论

有两个点要说一下： entityId 和entityType 一起 代表一个咨询。这里type即为news，而entityId 即为newsId.假如还有news,topics等等别的可以直接套用。

第二个就是删除评论，并不是直接删除，而是将status设置为1.

package com.nowcoder.dao;

import com.nowcoder.model.Comment;
import org.apache.ibatis.annotations.*;

import java.util.List;

/**
 * Created by Administrator on 2017/4/29.
 */
@Mapper
public interface CommentDao {
    String TABLE_NAME = "comment";
    String INSERT_FIELDS = "content, entity_id, entity_type, created_date, user_id, status";
    String SELECT_FIELDS = "id," + INSERT_FIELDS;

    @Insert({"insert into", TABLE_NAME, "(", INSERT_FIELDS,
            ") values(#{content},  #{entityId}, #{entityType}, #{createdDate}, #{userId}, #{status})" })
    int addCommnet(Comment comment);

    @Select({"select", SELECT_FIELDS, "from", TABLE_NAME,
            "where entity_id = #{entityId} and entity_type=#{entityType} order by id desc"})
    List<Comment> selectByEntity(@Param("entityId") int entityId, @Param("entityType") int entityType);

    @Select({"select count(id) from", TABLE_NAME,
            "where entity_id = #{entityId} and entity_type=#{entityType}"})
    int getCommentCount(@Param("entityId") int entityId, @Param("entityType") int entityType);

    @Update({"update", TABLE_NAME, "set status=#{status} where entity_id = #{entityId} and entity_type=#{entityType}"})
    void updateStatus(@Param("entityId") int entityId,
                      @Param("entityType") int entityType,
                      @Param("status") int status);

}

4. Service:

package com.nowcoder.service;

import com.nowcoder.dao.CommentDao;
import com.nowcoder.model.Comment;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

import java.util.List;

/**
 * Created by Administrator on 2017/4/29.
 */
@Service
public class CommentService {

    @Autowired
    CommentDao commentDao;

    public List<Comment> getCommentsByEntity(int entityId, int entityType){
        return commentDao.selectByEntity(entityId, entityType);
    }

    public int addComment(Comment comment){
        return commentDao.addCommnet(comment);
    }

    public int getCommentCount(int entityId, int entityType){
        return commentDao.getCommentCount(entityId, entityType);
    }

    public void deleteComment(int entityId, int entityType){
        //模拟删除评论，status=1表示会话失效即被删除不显示
        commentDao.updateStatus(entityId, entityType, 1);
    }

}

5.Controller:

(1)增加评论：

    /**
     * 增加评论
     * @param newsId
     * @param content
     * @return
     */
    @RequestMapping(path = {"/addComment"}, method = {RequestMethod.POST})
    public String addComment(@RequestParam("newsId") int newsId,
                             @RequestParam("content") String content){

        try{
            //防止评论中有转义字符
            content = HtmlUtils.htmlEscape(content);
            //过滤评论内容content

            Comment comment = new Comment();
            comment.setUserId(hostHolder.getUser().getId());
            comment.setEntityId(newsId);
            comment.setEntityType(EntityType.ENTITY_NEWS);
            comment.setContent(content);
            comment.setCreatedDate(new Date());
            comment.setStatus(0);//0 有效，1 表示评论被删除

            commentService.addComment(comment);

            //更新评论数量
            int count = commentService.getCommentCount(comment.getEntityId(), comment.getEntityType());
            newsService.updateCommentCount(comment.getEntityId(), count);
            //异步化更新数量
        }catch (Exception e){
            logger.error("增加评论失败!" + e.getMessage());
        }
        return "redirect:/news/" + String.valueOf(newsId);
    }

(2)显示评论：

    /**
     * 查看资讯详情页
     * @param newsId
     * @param model
     * @return
     */
    @RequestMapping(path = {"/news/{newsId}"}, method = {RequestMethod.GET})
    public String newsDetail(@PathVariable("newsId") int newsId, Model model){
        News news = newsService.getById(newsId);
        //显示评论内容
        if(news != null){
            List<Comment> commentList = commentService.getCommentsByEntity(news.getId(), EntityType.ENTITY_NEWS);
            List<ViewObject> commentVOs = new ArrayList<>();
            for(Comment comment : commentList){
                ViewObject vo = new ViewObject();
                vo.set("comment", comment);
                vo.set("user", userService.getUser(comment.getUserId()));
                commentVOs.add(vo);
            }
            model.addAttribute("comments", commentVOs);
        }

        //评论
        model.addAttribute("news", news);
        model.addAttribute("owner", userService.getUser(news.getUserId()));
        return "detail";
    }

6.HTML: detail.html

#parse("header.html")
<div id="main">
    <div class="container">
        <div class="post detail">

            <div class="votebar">
                #if($like>0)
                <button class="click-like up pressed" data-id="$!{news.id}" title="赞同"><i class="vote-arrow"></i><span class="count">$!{news.likeCount}</span></button>
                #else
                <button class="click-like up" data-id="$!{news.id}" title="赞同"><i class="vote-arrow"></i><span class="count">$!{news.likeCount}</span></button>
                #end
                #if($like<0)
                <button class="click-dislike down pressed" data-id="$!{news.id}" title="反对"><i class="vote-arrow"></i></button>
                #else
                <button class="click-dislike down" data-id="$!{news.id}" title="反对"><i class="vote-arrow"></i></button>
                #end
            </div>

            <div class="content">
                <div class="content-img">
                    <img src="$!{news.image}" >
                </div>
                <div class="content-main">
                    <h3 class="title">
                        <a target="_blank" rel="external nofollow" href="$!{news.link}">$!{news.title}</a>
                    </h3>
                    <div class="meta">
                        $!{news.link}
                              <span>
                                  <i class="fa icon-comment"></i> $!{news.commentCount}
                              </span>
                    </div>
                </div>
            </div>
            <div class="user-info">
                <div class="user-avatar">
                    <a href="/user/$!{owner.id}"><img width="32" class="img-circle" src="$!{owner.headUrl}"></a>
                </div>

            </div>

            <div class="subject-name">来自 <a href="/user/$!{owner.id}">$!{owner.name}</a></div>
        </div>

        <div class="post-comment-form">
            #if($user)
            <span>评论 ($!{news.commentCount})</span>
            <form method="post" action="/addComment">
                <input name="newsId" type="hidden" value="$!{news.id}">

                <div class="form-group text required comment_content">
                    <label class="text required sr-only">
                        <abbr title="required">*</abbr> 评论</label>
                    <textarea rows="5" class="text required comment-content form-control" name="content" id="content"></textarea>
                </div>
                <div class="text-right">
                    <input type="submit" name="commit" value="提 交" class="btn btn-default btn-info">
                </div>
            </form>
            #else
            <div class="login-actions">
                <a class="btn btn-success" href="/?pop=1">登录后评论</a>
            </div>
            #end
        </div>

        <div id="comments" class="comments">
            #foreach($commentvo in $comments)
            <div class="media">
                <a class="media-left" href="/user/$!{commentvo.user.id}">
                    <img src="$!{commentvo.user.headUrl}">
                </a>
                <div class="media-body">
                    <h4 class="media-heading">
                        <small class="date">$date.format(‘yyyy-MM-dd HH:mm:ss‘, $!{commentvo.comment.createdDate})
                        </small>
                    </h4>
                    <div>$!{commentvo.comment.content}</div>
                </div>
            </div>
            #end
        </div>

    </div>
    <script type="text/javascript">
          $(function(){

            // If really is weixin
            $(document).on(‘WeixinJSBridgeReady‘, function() {

              $(‘.weixin-qrcode-dropdown‘).show();

              var options = {
                "img_url": "",
                "link": "http://nowcoder.com/j/wt2rwy",
                "desc": "",
                "title": "读《Web 全栈工程师的自我修养》"
              };

              WeixinJSBridge.on(‘menu:share:appmessage‘, function (argv){
                WeixinJSBridge.invoke(‘sendAppMessage‘, options, function (res) {
                  // _report(‘send_msg‘, res.err_msg)
                });
              });

              WeixinJSBridge.on(‘menu:share:timeline‘, function (argv) {
                WeixinJSBridge.invoke(‘shareTimeline‘, options, function (res) {
                  // _report(‘send_msg‘, res.err_msg)
                });
              });

              // $(window).on(‘touchmove scroll‘, function() {
              //   if ((window.innerHeight + window.scrollY) >= document.body.offsetHeight) {
              //     $(‘div.backdrop‘).show();
              //     $(‘div.share-help‘).show();
              //   } else {
              //     $(‘div.backdrop‘).hide();
              //     $(‘div.share-help‘).hide();
              //   }
              // });

            });

          })

    </script>
    <script type="text/javascript" src="/scripts/main/site/detail.js"></script>
</div>
#parse("footer.html")