点赞功能的设计

点赞功能的设计

每一次点赞,需要记录:

(1)谁点的赞;

(2)为哪篇文章(Convention)点的赞;

(3)点赞时间

(4)是否已经取消点赞

数据表设计

点赞记录表

列名	数据类型扫描二维码关注公众号，回复： 686850 查看本文章	说明
id	N	数据表id
user_id	N	用户id
vote_time	S	点赞时间,格式”2016-02-22 12:01:45”
bbs_id	N	被点赞帖子id
status	N	状态:有效或取消

继续讨论E-R关系

点赞记录表与用户是多对1关系

点赞记录表与帖子也是多对1关系

实体类:

package com.girltest.entity;

import java.util.List;

import javax.persistence.*;

import org.hibernate.annotations.Fetch;
import org.hibernate.annotations.FetchMode;

/**
 * Created by huangweii on 2016/2/21.
 */
@Entity
@Table(name = "t_vote_log")
public class VoteLog {
    private int id;
    private User user;
    /**
     * 点赞的时间
     */
private String voteTime;
    private int status;
   /**
    * 帖子
    */
private Convention convention;
    
    @Id
    @GeneratedValue
public int getId() {
      return id;
   }
   public void setId(int id) {
      this.id = id;
   }

   @ManyToOne
   @JoinColumn (name="userId")
   public User getUser() {
      return user;
   }
   public void setUser(User user) {
      this.user = user;
   }
   @Column(name = "vote_time")
   public String getVoteTime() {
      return voteTime;
   }
   public void setVoteTime(String voteTime) {
      this.voteTime = voteTime;
   }
   public int getStatus() {
      return status;
   }
   public void setStatus(int status) {
      this.status = status;
   }

   @ManyToOne
   @JoinColumn (name="conventionId")
   public Convention getConvention() {
      return convention;
   }

   public void setConvention(Convention convention) {
      this.convention = convention;
   }
}

投票的控制器:

package com.girltest.web.controller;

import com.common.dict.Constant2;
import com.common.util.SystemHWUtil;
import com.girltest.dao.ConventionDao;
import com.girltest.dao.Test2BoyDao;
import com.girltest.dao.VoteLogDao;
import com.girltest.entity.Convention;
import com.girltest.entity.User;
import com.girltest.entity.VoteLog;
import com.io.hw.json.HWJacksonUtils;
import com.time.util.TimeHWUtil;
import oa.util.AuthenticateUtil;
import oa.web.controller.base.BaseController;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;

import javax.annotation.Resource;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;

@Controller
@RequestMapping("/vote")
public class VoteController extends BaseController<VoteLog> {
    private VoteLogDao voteLogDao;
    private ConventionDao conventionDao;
    private Test2BoyDao test2BoyDao;


    public VoteLogDao getVoteLogDao() {
        return voteLogDao;
    }

    @Resource
    public void setVoteLogDao(VoteLogDao voteLogDao) {
        this.voteLogDao = voteLogDao;
    }

    @Override
    protected void beforeAddInput(Model model) {
    }

    @Override
    protected void errorDeal(Model model) {
    }

    @Override
    public String getJspFolder() {
        return null;
    }

    /***
     * @param model
     * @param conventionId
     * @param testBoyId
     * @param session
     * @param request
     * @param callback
     * @return :result:2--未登录;3--已经投票过
     * @throws IOException
     */
    @ResponseBody
    @RequestMapping(value = "/vote", produces = SystemHWUtil.RESPONSE_CONTENTTYPE_JSON_UTF)
    public String jsonVote(Model model, int conventionId, int testBoyId, HttpSession session,
                           HttpServletRequest request, String callback) throws IOException {
        User user2 = (User) session.getAttribute(Constant2.SESSION_KEY_LOGINED_USER);
        Map map = new HashMap();
        if (!AuthenticateUtil.isLogined(session)) {
            map.put(Constant2.LOGIN_RESULT_KEY, Constant2.MODIFY_PASS_RESULT_NOT_LOGINED_YET);//没有登录
            return HWJacksonUtils.getJsonP(map, callback);
        }
        VoteLog voteLogTmp = this.voteLogDao.get("user.id", user2.getId(), "convention.id", conventionId);


        if (voteLogTmp == null) {//说明还没有点赞
            Convention convention = conventionDao.get(conventionId);
            VoteLog voteLog = new VoteLog();
            voteLog.setConvention(convention);
            voteLog.setUser(user2);
            voteLog.setVoteTime(TimeHWUtil.getCurrentFormattedTime());
            this.voteLogDao.save(voteLog);
            int stars = convention.getStars();
            conventionDao.updateSpecail(conventionId, "stars", stars + 1);
            test2BoyDao.updateTime(testBoyId);
//			map.put("voteCount", voteCount);

            map.put(Constant2.LOGIN_RESULT_KEY, Constant2.LOGIN_RESULT_SUCCESS);
        } else {
            //查询投票数
            /*Vote vote=this.voteDao.get("type", type, "houseBuilding.id", houseBuildingIdInt);
			map.put("voteCount", vote==null?0:vote.getVoteCount());*/
            map.put(Constant2.LOGIN_RESULT_KEY, 3);//已经投票过
        }
        return HWJacksonUtils.getJsonP(map, callback);
    }

   

    public ConventionDao getConventionDao() {
        return conventionDao;
    }

    @Resource
    public void setConventionDao(ConventionDao conventionDao) {
        this.conventionDao = conventionDao;
    }

    public Test2BoyDao getTest2BoyDao() {
        return test2BoyDao;
    }

    @Resource
    public void setTest2BoyDao(Test2BoyDao test2BoyDao) {
        this.test2BoyDao = test2BoyDao;
    }
}

ajax调用投票接口:

var voteConvention= function (self,conventionId,testBoyId) {
    var options = {
        url: server_url + "/vote/vote?conventionId=" + conventionId +'&testBoyId='+testBoyId,
        type: "POST",
        dataType: 'json',
        success: function (json2) {
            if (json2.result==1) {
                $(self).parent().text("已赞");
                //alert("点赞成功");
            }else if (json2.result==3) {
                alert("您已经点过赞")
            }
        },
        error: function (er) {
            console.log(er)
        }
    };
    $.ajax(options);
};

界面如下:

查询时需要知道点赞的数量:

点赞的数量(总数)就是Convention的成员变量stars,每次点赞时都会更新

还需要判断当前用户是否已经点过赞:

总结:

(1)点赞记录和用户是多对一的关系,即一个用户可以有多个点赞记录,但是一个点赞记录不可能属于多个用户;

(2)点赞的总记录存储在Convention中,而不是通过点赞记录查询到的,也就是说有两种方式获取一个帖子点了多少赞:

方式一:通过Convention中的stars;

方式二:查询点赞记录表

理论上,两种方式的结果是相同的.这里存在信息的冗余,冗余的目的是节约查询成本

数据表结构如下:

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