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

6.系统部署：

到这里，已经基本完工。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

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