最火的秒杀是如何实现的？

互扯程序

发布于 2018-10-25 11:33:00

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发布于 2018-10-25 11:33:00

文章被收录于专栏：互扯程序互扯程序

1、需求分析和技术难点：

(1) 分析：

秒杀的时候：减少库存和购买记录明细两个事件保持在同一个事物中。

使用联合查询避免同一用户多次秒杀同一商品（利用在插入购物明细表中的秒杀id和用户的唯一标识来避免）。

(2) 秒杀难点:事务和行级锁的处理

(3) 实现那些秒杀系统(以天猫的秒杀系统为例)

(4) 我们如何实现秒杀功能?

① 秒杀接口暴漏

② 执行秒杀

③ 相关查询

下面我们以主要代码实现秒杀系统：

PS：由于文章字符限制，没有办法将所有的代码列在文章中，大家可以在公众号内回复 ”秒杀“ 获取源码，方便您的学习

2.数据库设计和DAO层

(1) 数据库设计

(2) Dao层和对应的实体

① Seckill.java

② SuccessKilled.java

③ SeckillDao

④ SuccessKilledDao

⑤ mybatis配置文件：

⑥ SeckillDao.xml

⑦ SuccessKilledDao.xml

⑧ Mybatis整合Service：spring-dao.xml

3 Service层

① SeckillService

② SeckillServiceImpl

③ 异常的处理：

a.SeckillCloseException

b. SeckillException

c. RepeatKillException

④ 枚举SeckillStatEnum

⑤ spring_spring.xml文件

4.Web层,JSP页面和JS

(1) 详情页流程逻辑逻辑

(2) 配置web.xml

(3) SeckillResult

(4) spring-web.xml

(5) SeckillController中：

package com.force4us.web;
import com.force4us.dto.Exposer;
import com.force4us.dto.SeckillExecution;
import com.force4us.dto.SeckillResult;
import com.force4us.entity.Seckill;
import com.force4us.enums.SeckillStatEnum;
import com.force4us.exception.RepeatKillException;
import com.force4us.exception.SeckillCloseException;
import com.force4us.exception.SeckillException;
import com.force4us.service.SeckillService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.test.annotation.Repeat;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.*;
import java.util.Date;
import java.util.List;

@Controller
@RequestMapping("/seckill")
public class SeckillController {

    @Autowired
    private SeckillService seckillService;



    @RequestMapping(value = "/list",method= RequestMethod.GET)
    public String list(Model model) {
        List<Seckill> list = seckillService.getSeckillList();
        model.addAttribute("list",list);
        return "list";
    }

    @RequestMapping(value = "/{seckillId}/detail",method = RequestMethod.GET)
    public String detail(@PathVariable("seckillId") Long seckillId, Model model){
        if(seckillId == null){
            return "redirect:/seckill/list";
        }
        Seckill seckill = seckillService.getById(seckillId);
        if(seckill == null){
            return "forward:/seckill/list";
        }
        model.addAttribute("seckill", seckill);
        return "detail";
    }

    //ajax ,json暴露秒杀接口的方法
    @RequestMapping(value="/{seckillId}/exposer",method = RequestMethod.POST,produces = {"application/json;charset=UTF-8"})
    @ResponseBody
    public SeckillResult<Exposer> exposer(@PathVariable("seckillId") Long seckillId){
        SeckillResult<Exposer> result;

        try {
            Exposer exposer = seckillService.exportSeckillUrl(seckillId);
            result = new SeckillResult<Exposer>(true,exposer);
        } catch (Exception e) {
            e.printStackTrace();
            result = new SeckillResult<Exposer>(false,e.getMessage());
        }

        return result;
    }


    @RequestMapping(value="/{seckillId}/{md5}/execution", method = RequestMethod.POST,
                    produces = {"application/json;charset=UTF-8"})
    @ResponseBody
    public SeckillResult<SeckillExecution> execute(@PathVariable("seckillId") Long seckillId,
                                                   @PathVariable("md5") String md5,
                                                   @CookieValue(value="killPhone", required = false) Long phone){
        if(phone == null){
            return new SeckillResult<SeckillExecution>(false,"未注册");
        }

        SeckillResult<SeckillExecution> result;

        try {
            SeckillExecution execution = seckillService.executeSeckillProcedure(seckillId,phone, md5);
            return new SeckillResult<SeckillExecution>(true,execution);
        } catch (RepeatKillException e1) {
            SeckillExecution execution = new SeckillExecution(seckillId, SeckillStatEnum.REPEAT_KILL);
            return new SeckillResult<SeckillExecution>(true,execution);
        } catch(SeckillCloseException e2){
            SeckillExecution execution = new SeckillExecution(seckillId, SeckillStatEnum.END);
            return new SeckillResult<SeckillExecution>(true,execution);
        }catch(Exception e){
            SeckillExecution execution = new SeckillExecution(seckillId, SeckillStatEnum.INNER_ERROR);
            return new SeckillResult<SeckillExecution>(true,execution);
        }
    }

    @RequestMapping(value = "/time/now", method = RequestMethod.GET)
    @ResponseBody
    public SeckillResult<Long> time(){
        Date now = new Date();
        return new SeckillResult<Long>(true,now.getTime());
    }


    @RequestMapping("/test")
    public String test(){
        return "helloworld";
    }
}

(6) list.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@include file="common/tag.jsp"%>
<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
    <title>秒杀列表页</title>
    <%@include file="/WEB-INF/jsp/common/head.jsp"%>

</head>
<body>

<div class="container">
    <div class="panel panel-default">
        <div class="panel-heading text-center">
            <h2>秒杀列表</h2>
        </div>
        <div class="panel-body">
            <table class="table table-hover">
                <thead>
                <tr>
                    <th>名称</th>
                    <th>库存</th>
                    <th>开始时间</th>
                    <th>结束时间</th>
                    <th>创建时间</th>
                    <th>详情页</th>
                </tr>
                </thead>
                <tbody>
                <c:forEach items="${list}" var="sk">
                    <tr>
                        <td>${sk.name}</td>
                        <td>${sk.number}</td>
                        <td>
                            <fmt:formatDate value="${sk.startTime}" pattern="yyyy-MM-dd HH:mm:ss" />
                        </td>
                        <td>
                            <fmt:formatDate value="${sk.endTime}" pattern="yyyy-MM-dd HH:mm:ss" />
                        </td>
                        <td>
                            <fmt:formatDate value="${sk.createTime}" pattern="yyyy-MM-dd HH:mm:ss" />
                        </td>
                        <td><a class="btn btn-info" href="/seckill/${sk.seckillId}/detail" target="_blank">详情</a></td>
                    </tr>
                </c:forEach>
                </tbody>
            </table>

        </div>
    </div>
</div>

</body>
<!-- jQuery (necessary for Bootstrap's JavaScript plugins) -->
<script src="https://cdn.bootcss.com/jquery/1.12.4/jquery.min.js"></script>

<!-- 最新的 Bootstrap 核心 JavaScript 文件 -->
<script src="https://cdn.bootcss.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>

</html>

(7) details.jsp

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@include file="common/tag.jsp"%>
<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="utf-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <!-- 上述3个meta标签*必须*放在最前面，任何其他内容都*必须*跟随其后！ -->
    <title>秒杀详情页</title>
    <%@include file="common/head.jsp"%>

</head>
<body>

<div class="container">
    <div class="panel panel-default text-center">
        <div class="pannel-heading">
            <h1>${seckill.name}</h1>
        </div>

        <div class="panel-body">
            <h2 class="text-danger">
                <%--显示time图标--%>
                <span class="glyphicon glyphicon-time"></span>
                <%--展示倒计时--%>
                <span class="glyphicon" id="seckill-box"></span>
            </h2>
        </div>
    </div>
</div>

<%--登录弹出层 输入电话--%>
<div id="killPhoneModal" class="modal fade">

    <div class="modal-dialog">

        <div class="modal-content">
            <div class="modal-header">
                <h3 class="modal-title text-center">
                    <span class="glyphicon glyphicon-phone"> </span>秒杀电话:
                </h3>
            </div>

            <div class="modal-body">
                <div class="row">
                    <div class="col-xs-8 col-xs-offset-2">
                        <input type="text" name="killPhone" id="killPhoneKey"
                              placeholder="填写手机号^o^" class="form-control">
                    </div>
                </div>
            </div>

            <div class="modal-footer">
                <%--验证信息--%>
                <span id="killPhoneMessage" class="glyphicon"> </span>
                <button type="button" id="killPhoneBtn" class="btn btn-success">
                    <span class="glyphicon glyphicon-phone"></span>
                    Submit
                </button>
            </div>

        </div>
    </div>

</div>

</body>
<!-- jQuery (necessary for Bootstrap's JavaScript plugins) -->
<script src="https://cdn.bootcss.com/jquery/1.12.4/jquery.min.js"></script>

<!-- 最新的 Bootstrap 核心 JavaScript 文件 -->
<script src="https://cdn.bootcss.com/bootstrap/3.3.7/js/bootstrap.min.js" integrity="sha384-Tc5IQib027qvyjSMfHjOMaLkfuWVxZxUPnCJA7l2mCWNIpG9mGCD8wGNIcPD7Txa" crossorigin="anonymous"></script>
<%--jQuery Cookie操作插件--%>
<script src="https://cdn.bootcss.com/jquery-cookie/1.4.1/jquery.cookie.min.js"></script>
<%--jQuery countDown倒计时插件--%>
<script src="https://cdn.bootcss.com/jquery.countdown/2.2.0/jquery.countdown.min.js"></script>

<script src="/resource/script/seckill.js" typ="text/javascript"></script>

<script type="text/javascript">
    $(function(){
        seckill.detail.init({
            seckillId:${seckill.seckillId},
            startTime:${seckill.startTime.time},
            endTime:${seckill.endTime.time}
        });
    })

</script>
</html>

(8) seckill.js

//存放主要交互逻辑的js代码
// javascript 模块化(package.类.方法)

var seckill = {
    //封装秒杀相关ajax的url
    URL: {
        now: function () {
            return '/seckill/time/now';
        },
        exposer: function (seckillId) {
            return '/seckill/' + seckillId + '/exposer';
        },
        execution: function (seckillId, md5) {
            return '/seckill/' + seckillId + '/' + md5 + '/execution';
        }
    },

    //验证手机号
    validatePhone: function(phone){
      if(phone && phone.length == 11 && !isNaN(phone)){
            return true;
      }else{
          return false;
      }

    },

    //详情页秒杀逻辑
    detail:{
        //详情页初始化
        init:function (params) {
            //手机验证和登录，计时交互
            //规划我们的交互流程
            //在cookie中查找手机号
            var killPhone = $.cookie('killPhone');
            //验证手机号
            if(!seckill.validatePhone(killPhone)){
                //绑定手机，控制输出
                var killPhoneModal = $('#killPhoneModal');
                killPhoneModal.modal({
                    show:true,//显示弹出层
                    backdrop:'static',//禁止位置关闭
                    keyboard:false//关闭键盘事件
                });

                $('#killPhoneBtn').click(function () {
                    var inputPhone = $('#killPhoneKey').val();
                    console.log("inputPhone" + inputPhone);
                    if(seckill.validatePhone(inputPhone)){
                        //电话写入cookie，7天过期
                        $.cookie('killPhone',inputPhone,{expires:7, path:'/seckill'});
                        //验证通过，刷新页面
                        window.location.reload();
                    }else{
                        $('#killPhoneMessage').hide().html('<label class="label label-danger">手机号错误</label>').show(300);
                    }
                });
            }
            //已经登录
            //计时交互

            var startTime = params['startTime'];
            var endTime = params['endTime'];
            var seckillId = params['seckillId'];
            $.get(seckill.URL.now(), {}, function (result) {
                if (result && result['success']) {
                    var nowTime = result['data'];
                    //时间判断 计时交互
                    seckill.countDown(seckillId, nowTime, startTime, endTime);
                } else {
                    console.log('result: ' + result);
                    alert('result: ' + result);
                }
            });
        }
    },

    handlerSeckill: function (seckillId, node) {
        //获取秒杀地址,控制显示器,执行秒杀
        node.hide().html('<button class="btn btn-primary btn-lg" id="killBtn">开始秒杀</button>');

        $.post(seckill.URL.exposer(seckillId), {}, function (result) {
            //在回调函数种执行交互流程
            if (result && result['success']) {
                var exposer = result['data'];
                if (exposer['exposed']) {
                    //开启秒杀
                    //获取秒杀地址
                    var md5 = exposer['md5'];
                    var killUrl = seckill.URL.execution(seckillId, md5);
                    console.log("killUrl: " + killUrl);
                    //绑定一次点击事件
                    $('#killBtn').one('click', function () {
                        //执行秒杀请求
                        //1.先禁用按钮
                        $(this).addClass('disabled');//,<-$(this)===('#killBtn')->
                        //2.发送秒杀请求执行秒杀
                        $.post(killUrl, {}, function (result) {
                            if (result && result['success']) {
                                var killResult = result['data'];
                                var state = killResult['state'];
                                var stateInfo = killResult['stateInfo'];
                                //显示秒杀结果
                                node.html('<span class="label label-success">' + stateInfo + '</span>');
                            }
                        });
                    });
                    node.show();
                } else {
                    //未开启秒杀(浏览器计时偏差)
                    var now = exposer['now'];
                    var start = exposer['start'];
                    var end = exposer['end'];
                    seckill.countDown(seckillId, now, start, end);
                }
            } else {
                console.log('result: ' + result);
            }
        });

    },


    countDown: function (seckillId, nowTime, startTime, endTime) {
        console.log(seckillId + '_' + nowTime + '_' + startTime + '_' + endTime);
        var seckillBox = $('#seckill-box');
        if (nowTime > endTime) {
            //秒杀结束
            seckillBox.html('秒杀结束!');
        } else if (nowTime < startTime) {
            //秒杀未开始,计时事件绑定
            var killTime = new Date(startTime + 1000);//todo 防止时间偏移
            seckillBox.countdown(killTime, function (event) {
                //时间格式
                var format = event.strftime('秒杀倒计时: %D天 %H时 %M分 %S秒 ');
                seckillBox.html(format);
            }).on('finish.countdown', function () {
                //时间完成后回调事件
                //获取秒杀地址,控制现实逻辑,执行秒杀
                console.log('______fininsh.countdown');
                seckill.handlerSeckill(seckillId, seckillBox);
            });
        } else {
            //秒杀开始
            seckill.handlerSeckill(seckillId, seckillBox);
        }
    }
}

5.优化：

由于减少库存和购买明细需要在同一事物当中，在次中间会出现网络延迟，GC，缓存，数据库的并发等，所以需要进行优化。

(1) 使用Redis优化：具体代码看上面。

(2) 调整业务逻辑：先进行insert，插入购买明细，然后进行减少库存数量，具体代码看上面。

(3) 调用存储过程seckill.sql