前言
秒杀的业务场景广泛存在于电商当中,即有一个倒计时的时间限制,当倒计时为0时,秒杀开始,秒杀之后持续很小的一段时间,而且秒杀的商品很少,因此会有大量的顾客进行购买,会产生很大的并发量,从而创造技术难点
本章将编写一个不涉及并发操作的秒杀逻辑实现,包括商品页面,详情页面,以及订单页面。
首先,当用户登录之后,跳转到商品页面,罗列了所有可以秒杀的商品。
@Autowired
private GoodsService goodsService;
@RequestMapping("/to_list")
public String list(Model model,MiaoshaUser user ){
List<GoodsVo> goodsList = goodsService.listGoodsVo();
model.addAttribute("user",user);
model.addAttribute("goodsList",goodsList);
return "goods_list";
}
代码如上所示,这里之所以能取到user,是利用了分布式session的设计。
- 商品页面代码
<!DOCTYPE HTML>
<html xmlns:th="http://www.thymeleaf.org">
<head>
<title>商品列表</title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<!-- jquery -->
<script type="text/javascript" th:src="@{/js/jquery.min.js}"></script>
<!-- bootstrap -->
<link rel="stylesheet" type="text/css" th:href="@{/bootstrap/css/bootstrap.min.css}" />
<script type="text/javascript" th:src="@{/bootstrap/js/bootstrap.min.js}"></script>
<!-- jquery-validator -->
<script type="text/javascript" th:src="@{/jquery-validation/jquery.validate.min.js}"></script>
<script type="text/javascript" th:src="@{/jquery-validation/localization/messages_zh.min.js}"></script>
<!-- layer -->
<script type="text/javascript" th:src="@{/layer/layer.js}"></script>
<!-- md5.js -->
<script type="text/javascript" th:src="@{/js/md5.min.js}"></script>
<!-- common.js -->
<script type="text/javascript" th:src="@{/js/common.js}"></script>
</head>
<body>
<div class="panel panel-default">
<div class="panel-heading">秒杀商品列表</div>
<table class="table" id="goodslist">
<tr><td>商品名称</td><td>商品图片</td><td>商品原价</td><td>秒杀价</td><td>库存数量</td><td>详情</td></tr>
<tr th:each="goods,goodsStat : ${goodsList}">
<td th:text="${goods.goodsName}"></td>
<td ><img th:src="@{${goods.goodsImg}}" width="100" height="100" /></td>
<td th:text="${goods.goodsPrice}"></td>
<td th:text="${goods.miaoshaPrice}"></td>
<td th:text="${goods.stockCount}"></td>
<td><a th:href="'/goods/to_detail/'+${goods.id}">详情</a></td>
</tr>
</table>
</div>
</body>
</html>
View Code
从商品页面代码,点击详情的超链接可以到达去商品详情的控制器
@RequestMapping("/to_detail/{goodsId}")
public String detail(Model model, MiaoshaUser user,
@PathVariable("goodsId") long goodsId){
model.addAttribute("user",user);
GoodsVo goods = goodsService.getGoodsVoByGoodsId(goodsId);
model.addAttribute("goods", goods);
//得到秒杀的开始时间、结束时间、以及当前时间
long startAt = goods.getStartDate().getTime();
long endAt = goods.getEndDate().getTime();
long now = System.currentTimeMillis();
//设置剩余时间
int remainSeconds=0;
//设置秒杀状态
int miaoshaStatus=0;
//判断
if(now<startAt){
//秒杀还没开始
miaoshaStatus=0;
remainSeconds= (int) ((startAt-now)/1000);
}else if(now>endAt){
//秒杀已经结束
miaoshaStatus=2;
remainSeconds=-1;
}else {
//秒杀正在进行
miaoshaStatus=1;
remainSeconds=0;
}
model.addAttribute("miaoshaStatus",miaoshaStatus);
model.addAttribute("remainSeconds",remainSeconds);
return "goods_detail";
}
该方法从页面传来商品id的值,然后从数据库中取出该商品的秒杀开始时间。结束时间等,判断秒杀的状态,0为未开始,1为正在进行,2为已经结束。然后返回商品详情。剩余时间、以及秒杀的状态,然后跳转到商品的详情页面,在详情页面中,详细列出该商品的信息。
详情页代码
<!DOCTYPE HTML>
<html xmlns:th="http://www.thymeleaf.org">
<head>
<title>商品详情</title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<!-- jquery -->
<script type="text/javascript" th:src="@{/js/jquery.min.js}"></script>
<!-- bootstrap -->
<link rel="stylesheet" type="text/css" th:href="@{/bootstrap/css/bootstrap.min.css}" />
<script type="text/javascript" th:src="@{/bootstrap/js/bootstrap.min.js}"></script>
<!-- jquery-validator -->
<script type="text/javascript" th:src="@{/jquery-validation/jquery.validate.min.js}"></script>
<script type="text/javascript" th:src="@{/jquery-validation/localization/messages_zh.min.js}"></script>
<!-- layer -->
<script type="text/javascript" th:src="@{/layer/layer.js}"></script>
<!-- md5.js -->
<script type="text/javascript" th:src="@{/js/md5.min.js}"></script>
<!-- common.js -->
<script type="text/javascript" th:src="@{/js/common.js}"></script>
</head>
<body>
<div class="panel panel-default">
<div class="panel-heading">秒杀商品详情</div>
<div class="panel-body">
<span th:if="${user eq null}"> 您还没有登录,请登陆后再操作<br/></span>
<span>没有收货地址的提示。。。</span>
</div>
<table class="table" id="goodslist">
<tr>
<td>商品名称</td>
<td colspan="3" th:text="${goods.goodsName}"></td>
</tr>
<tr>
<td>商品图片</td>
<td colspan="3"><img th:src="@{${goods.goodsImg}}" width="200" height="200" /></td>
</tr>
<tr>
<td>秒杀开始时间</td>
<td th:text="${#dates.format(goods.startDate, 'yyyy-MM-dd HH:mm:ss')}"></td>
<td id="miaoshaTip">
<input type="hidden" id="remainSeconds" th:value="${remainSeconds}" />
<span th:if="${miaoshaStatus eq 0}">秒杀倒计时:<span id="countDown" th:text="${remainSeconds}"></span>秒</span>
<span th:if="${miaoshaStatus eq 1}">秒杀进行中</span>
<span th:if="${miaoshaStatus eq 2}">秒杀已结束</span>
</td>
<td>
<form id="miaoshaForm" method="post" action="/miaosha/do_miaosha">
<button class="btn btn-primary btn-block" type="submit" id="buyButton">立即秒杀</button>
<input type="hidden" name="goodsId" th:value="${goods.id}" />
</form>
</td>
</tr>
<tr>
<td>商品原价</td>
<td colspan="3" th:text="${goods.goodsPrice}"></td>
</tr>
<tr>
<td>秒杀价</td>
<td colspan="3" th:text="${goods.miaoshaPrice}"></td>
</tr>
<tr>
<td>库存数量</td>
<td colspan="3" th:text="${goods.stockCount}"></td>
</tr>
</table>
</div>
</body>
<script>
$(function(){
countDown();
});
function countDown(){
var remainSeconds = $("#remainSeconds").val();
var timeout;
if(remainSeconds > 0){//秒杀还没开始,倒计时
$("#buyButton").attr("disabled", true);
timeout = setTimeout(function(){
$("#countDown").text(remainSeconds - 1);
$("#remainSeconds").val(remainSeconds - 1);
countDown();
},1000);
}else if(remainSeconds == 0){//秒杀进行中
$("#buyButton").attr("disabled", false);
if(timeout){
clearTimeout(timeout);
}
$("#miaoshaTip").html("秒杀进行中");
}else{//秒杀已经结束
$("#buyButton").attr("disabled", true);
$("#miaoshaTip").html("秒杀已经结束");
}
}
</script>
</html>
View Code
详情页代码没有什么技术难点,主要有一个倒计时的功能,当确定秒杀还没有开始的时候,会显示一个倒计时,代码如下
function countDown(){
var remainSeconds = $("#remainSeconds").val();
var timeout;
if(remainSeconds > 0){//秒杀还没开始,倒计时
$("#buyButton").attr("disabled", true);
timeout = setTimeout(function(){
$("#countDown").text(remainSeconds - 1);
$("#remainSeconds").val(remainSeconds - 1);
countDown();
},1000);
}else if(remainSeconds == 0){//秒杀进行中
$("#buyButton").attr("disabled", false);
if(timeout){
clearTimeout(timeout);
}
$("#miaoshaTip").html("秒杀进行中");
}else{//秒杀已经结束
$("#buyButton").attr("disabled", true);
$("#miaoshaTip").html("秒杀已经结束");
}
该方法通过判断剩余时间,如果剩余时间大于0,则,一直循环减1,如果进入秒杀则清理时间。
立即秒杀按钮是通过form表单提交的,会跳转到处理秒杀的控制器中,实际来说,秒杀有两个步骤,一个减少库存,一个写入订单。这两个步骤需要构成一个事务,如果其中一个出错,就需要回滚。这里可以使用事务注解@Transactional
来解决。
秒杀控制器
@Controller
@RequestMapping("/miaosha")
public class MiaoshaController {
@Autowired
private GoodsService goodsService;
@Autowired
private OrderService orderService;
@Autowired
private MiaoshaService miaoshaService;
@RequestMapping("/do_miaosha")
public String list(Model model, MiaoshaUser user,
@RequestParam("goodsId") long goodsId){
model.addAttribute("user",user);
if(user==null){
//如果没有获取到user值,就跳转到登录页面去
return "login";
}
//判断库存
GoodsVo goods = goodsService.getGoodsVoByGoodsId(goodsId);
Integer stock= goods.getStockCount();
if(stock<=0){
model.addAttribute("errmsg", CodeMsg.MIAO_SHA_OVER.getMsg());
return "miaosha_fail";
}
//判断是否已经秒杀到了
MiaoshaOrder order=orderService.getMiaoshaOrderByUserIdGoodsId(user.getId(), goodsId);
if(order!=null){
model.addAttribute("errmsg",CodeMsg.REPEATE_MIAOSHA.getMsg());
return "miaosha_fail";
}
//进行秒杀逻辑
//减库存,下订单,写入秒杀订单
OrderInfo orderInfo=miaoshaService.miaosha(user, goods);
model.addAttribute("orderInfo",orderInfo);
model.addAttribute("goods",goods);
return "order_detail";
}
}
View Code
首先获取user的值,获取不到,则跳转到登录页面,然后从商品数据库中获取库存,若大于0,则继续,否则跳转秒杀失败页面,然后判断是否秒杀商品已经在订单里了,如果在,也跳转到失败页面,因为不能重复秒杀。当前面的都没有问题,才开始进行秒杀操作,首先是减少库存,然后创建新订单。
具体秒杀逻辑代码
@Transactional
public OrderInfo miaosha(MiaoshaUser user, GoodsVo goods) {
//减库存,下订单,写入秒杀订单
goodsService.reduceStock(goods);
//抛出异常
// int i=1/0;
return orderService.createOrder(user, goods);
}
减库存代码
public void reduceStock(GoodsVo goods) {
MiaoshaGoods g = new MiaoshaGoods();
g.setGoodsId(goods.getId());
goodsDao.reduceStock(g);
}
下订单代码
@Transactional
public OrderInfo createOrder(MiaoshaUser user, GoodsVo goods) {
OrderInfo orderInfo=new OrderInfo();
//设置订单详情
orderInfo.setCreateDate(new Date());
orderInfo.setDeliveryAddrId(0L);
orderInfo.setGoodsCount(1);
orderInfo.setGoodsId(goods.getId());
orderInfo.setGoodsName(goods.getGoodsName());
orderInfo.setGoodsPrice(goods.getGoodsPrice());
orderInfo.setGoodsPrice(goods.getGoodsPrice());
orderInfo.setStatus(0);
orderInfo.setOrderChannel(1);
orderInfo.setUserId(user.getId());
//保存订单
long orderId = orderDao.insert(orderInfo);
//保存秒杀订单
MiaoshaOrder miaoshaOrder=new MiaoshaOrder();
miaoshaOrder.setGoodsId(goods.getId());
miaoshaOrder.setOrderId(orderId);
miaoshaOrder.setUserId(user.getId());
//抛出异常
//保存秒杀订单
orderDao.insertMiaoshaOrder(miaoshaOrder);
return orderInfo;
}
至此,一个简单的秒杀功能已经实现,但这样的秒杀逻辑肯定不能抗住高并发,接下来将继续优化。