Java 高并发秒杀系统架构（一）

比眉伴天荒 2022-03-21 08:12 338阅读 0赞

# 1 开场白 #

## 1.1 项目概述 ##

# ![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d5ZHlkMTEw_size_16_color_FFFFFF_t_70][] #

重点：缓存+异步+分布式+优雅的代码

## **1.2 项目开发环境与框架搭建** ##

基于Spring Boot搭建项目

Spring MVC配置繁多，而Spring Boot只有一个配置文件application.properties

> [参考：《Spring Boot 入门教程 》][Spring Boot _]

### 1.2.1 集成MyBatis ###

[参考文档][Link 1]

> @Transactional @Mapper @Select

### 1.2.2 Linux下部署Redis ###

> [参考：《Redis基础教程》][Redis] [官网][Link 2] [官方安装文档][Link 3]

下载redis安装文件 http://redis.io/ redis-5.0.4.tar.gz  
tar -zvxf redis-5.0.4.tar.gz  
cd redis-5.0.4  
make -j 4（用4个cpu加快编译）  
make install

建议通读redis.conf

![20190429151554472.png][]

vi ./redis.conf

![20190429151702760.png][]

默认只有本机可以访问redis，设置为0.0.0.0，允许任意服务器访问

![20190429152024852.png][]

：/dae搜索，设为yes允许后台执行  
redis-server ./redis.conf 启动服务器，先在etc/profile文件配置路径  
redis-cli 客户端连接

安全起见，添加一个访问密码

![20190429153852242.png][]

重启一下再访问就要输密码了

![20190429154140594.png][]

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d5ZHlkMTEw_size_16_color_FFFFFF_t_70 1][]

![20190429153839267.png][]

cd utils ./install\_server.sh 安装成系统服务

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d5ZHlkMTEw_size_16_color_FFFFFF_t_70 2][]![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d5ZHlkMTEw_size_16_color_FFFFFF_t_70 3][]  
chkconfig –-list | grep redis 查看是否开机启动

### **1.2.3 项目中集成Redis** ###

添加Jedis依赖

添加Fastjson依赖：负责将Java对象转换成Json字符串，写入Redis服务器

![20190310182703647.png][]

不同功能模块使用不同的key前缀

public interface KeyPrefix {
    		
    	public int expireSeconds();
    	
    	public String getPrefix();
    	
    }

public abstract class BasePrefix implements KeyPrefix{
    	
    	private int expireSeconds;
    	
    	private String prefix;
    	
    	public BasePrefix(String prefix) {//0代表永不过期
    		this(0, prefix);
    	}
    	
    	public BasePrefix( int expireSeconds, String prefix) {
    		this.expireSeconds = expireSeconds;
    		this.prefix = prefix;
    	}
    	
    	public int expireSeconds() {//默认0代表永不过期
    		return expireSeconds;
    	}
    
    	public String getPrefix() {
    		String className = getClass().getSimpleName();
    		return className+":" + prefix;
    	}
    
    }

public class GoodsKey extends BasePrefix{
    
    	private GoodsKey(int expireSeconds, String prefix) {
    		super(expireSeconds, prefix);
    	}
    	public static GoodsKey getGoodsList = new GoodsKey(60, "gl");
    	public static GoodsKey getGoodsDetail = new GoodsKey(60, "gd");
    	public static GoodsKey getMiaoshaGoodsStock= new GoodsKey(0, "gs");
    }

public class MiaoshaKey extends BasePrefix{
    
    	private MiaoshaKey( int expireSeconds, String prefix) {
    		super(expireSeconds, prefix);
    	}
    	public static MiaoshaKey isGoodsOver = new MiaoshaKey(0, "go");
    	public static MiaoshaKey getMiaoshaPath = new MiaoshaKey(60, "mp");
    	public static MiaoshaKey getMiaoshaVerifyCode = new MiaoshaKey(300, "vc");
    }

//取缓存
    String html = redisService.get(GoodsKey.getGoodsDetail, ""+goodsId, String.class);
    if(!StringUtils.isEmpty(html)) {
        	return html;
    }

### 1.2.4 项目集成Druid ###

数据库连接池负责分配，管理和释放连接，实际上是个生产者消费者模式，生产者是连接创建线程和连接回收线程，消费者是获取连接的线程。

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d5ZHlkMTEw_size_16_color_FFFFFF_t_70 4][]

Druid是阿里巴巴的一个数据库连接池开源框架。当应用启动时，连接池初始化最小连接数MIN，当外部请求到达时，直接使用空闲连接即可。并发数达到最大MAX，则需要等待，直到超时。如果一直没拿到连接，就会抛出异常。

MIN过小，会出现过多请求排队等待获取连接

MIN过大，会造成资源浪费

MAX过小，峰值情况下仍有很多请求在等待状态

MAX过大，导致数据库连接被占满，大量请求超时，引发服务器雪崩

若数据库配置的MAX是100，一个请求10ms，则最大能够处理10000QPS。（1s=1000ms=100\*10ms）

# 2 实现用户登录以及分布式session功能 #

## 2.1 前端校验用于登录的手机号 ##

[jQuery Validate][]

## 2.2 数据库设计 ##

**miaosha\_user表**

CREATE TABLE `miaosha_user` (
      `id` bigint(20) NOT NULL COMMENT '用户ID，手机号码',
      `nickname` varchar(255) NOT NULL,
      `password` varchar(32) DEFAULT NULL COMMENT 'MD5(MD5(pass明文+固定salt) + salt)',
      `salt` varchar(10) DEFAULT NULL,
      `head` varchar(128) DEFAULT NULL COMMENT '头像，云存储的ID',
      `register_date` datetime DEFAULT NULL COMMENT '注册时间',
      `last_login_date` datetime DEFAULT NULL COMMENT '上蔟登录时间',
      `login_count` int(11) DEFAULT '0' COMMENT '登录次数',
      PRIMARY KEY (`id`)
    ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;

## ![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d5ZHlkMTEw_size_16_color_FFFFFF_t_70 5][] ##

salt存放数据库随机生成的salt

## 2.3 明文密码两次MD5处理 ##

HTTP协议是明文传输，输入密码后若直接发送服务端验证，此时被截取将直接获取到明文密码，获取用户信息。

**用户端（第一次MD5）**

用户登录时输入明文密码，生成一个固定Salt，与该密码拼装后进行第一次MD5处理，然后传输给服务器端。

PASS = MD5（明文密码 + 固定Salt）

第一次MD5防止明文密码在网络传输时被盗

**服务端（第二次MD5）**

服务器端接收到进行了第一次MD5处理后的密码时，要生成一个随机的Salt，与密码进行拼装后再进行第二次MD5，最后才写入数据库。

PASS = MD5（密码 + 随机Salt）

第二次MD5防止数据库被入侵时，密码被反查

import org.apache.commons.codec.digest.DigestUtils;
    
    public class MD5Util {
    	
    	public static String md5(String src) {
    		return DigestUtils.md5Hex(src);
    	}
    	
            //固定盐值
    	private static final String salt = "1a2b3c4d";
    	
            //第一次MD5，明文密码+固定Salt
    	public static String inputPassToFormPass(String inputPass) {
    		String str = ""+salt.charAt(0)+salt.charAt(2) + inputPass +salt.charAt(5) + salt.charAt(4);
    		System.out.println(str);
    		return md5(str);
    	}
    	
    
            //第二次MD5，密码+随机Salt
    	public static String formPassToDBPass(String formPass, String salt) {
    		String str = ""+salt.charAt(0)+salt.charAt(2) + formPass +salt.charAt(5) + salt.charAt(4);
    		return md5(str);
    	}
    	
            //最终调用生成密码的方法
    	public static String inputPassToDbPass(String inputPass, String saltDB) {
    		String formPass = inputPassToFormPass(inputPass);
    		String dbPass = formPassToDBPass(formPass, saltDB);
    		return dbPass;
    	}
    }

## 2.4 登录功能实现 ##

**login.html**

......
    <script>
    function login(){
    	$("#loginForm").validate({
            submitHandler:function(form){
                 doLogin();
            }    
        });
    }
    function doLogin(){
    	g_showLoading();
    	
    	var inputPass = $("#password").val();
    	var salt = g_passsword_salt;
            //明文密码 + 固定Salt
    	var str = ""+salt.charAt(0)+salt.charAt(2) + inputPass +salt.charAt(5) + salt.charAt(4);
            //前端进行第一次MD5处理
    	var password = md5(str);
    	
    	$.ajax({
    	    url: "/login/do_login",
    	    type: "POST",
    	    data:{
    	    	mobile:$("#mobile").val(),
    	    	password: password
    	    },
    	    success:function(data){
    	    	layer.closeAll();
    	    	if(data.code == 0){
    	    		layer.msg("成功");
    	    		window.location.href="/goods/to_list";
    	    	}else{
    	    		layer.msg(data.msg);
    	    	}
    	    },
    	    error:function(){
    	    	layer.closeAll();
    	    }
    	});
    }
    </script>
    ......

**common.js**

var g_passsword_salt="1a2b3c4d"

**LoginVo.java**

public class LoginVo {
    	
    	@NotNull
    	@IsMobile
    	private String mobile;
    	
    	@NotNull
    	@Length(min=32)
    	private String password;
    	
    	public String getMobile() {
    		return mobile;
    	}
    	public void setMobile(String mobile) {
    		this.mobile = mobile;
    	}
    	...
    	public String toString() {
    		return "LoginVo [mobile=" + mobile + ", password=" + password + "]";
    	}
    }

**MiaoshaUser.java**

public class MiaoshaUser {
    	private Long id;
    	private String nickname;
    	private String password;
    	private String salt;
    	private String head;
    	private Date registerDate;
    	private Date lastLoginDate;
    	private Integer loginCount;
    	public Long getId() {
    		return id;
    	}
    	public void setId(Long id) {
    		this.id = id;
    	}
    	......
    }

**LoginController.java**

@Controller
    @RequestMapping("/login")
    public class LoginController {
    
        private static Logger log = LoggerFactory.getLogger(LoginController.class);
    	
        @Autowired
        MiaoshaUserService miaoshaUserService ;
    	
        @RequestMapping("/to_login")
        public String toLogin() {
            return "login";
        }
        
        @RequestMapping("/do_login")
        @ResponseBody
        public Result<String> doLogin(HttpServletResponse response, @Valid LoginVo loginVo) {
            //输出日志
        	log.info(loginVo.toString());
        	//登录
        	String token = miaoshaUserService.login(response, loginVo);
        	return Result.success(token);
        }
    }

**MiaoshaUserService.java**

@Service
    public class MiaoshaUserService {
    	
    	public static final String COOKI_NAME_TOKEN = "token";
    	
    	@Autowired
    	MiaoshaUserDao miaoshaUserDao;
    	
    	@Autowired
    	RedisService redisService;
    	
    	...
    	
    	public String login(HttpServletResponse response, LoginVo loginVo) {
    		if(loginVo == null) {
    			throw new GlobalException(CodeMsg.SERVER_ERROR);
    		}
    		String mobile = loginVo.getMobile();
    		String formPass = loginVo.getPassword();
    		//判断手机号是否存在
    		MiaoshaUser user = getById(Long.parseLong(mobile));
    		if(user == null) {
    			throw new GlobalException(CodeMsg.MOBILE_NOT_EXIST);
    		}
    		//验证密码
    		String dbPass = user.getPassword();
    		String saltDB = user.getSalt();
    		String calcPass = MD5Util.formPassToDBPass(formPass, saltDB);
    		if(!calcPass.equals(dbPass)) {
    			throw new GlobalException(CodeMsg.PASSWORD_ERROR);
    		}
    		//生成cookie
    		String token	 = UUIDUtil.uuid();
    		addCookie(response, token, user);
    		return token;
    	}
            ...
    }

**MiaoshaUserDao.java**

@Mapper
    public interface MiaoshaUserDao {
    	
    	@Select("select * from miaosha_user where id = #{id}")
    	public MiaoshaUser getById(@Param("id")long id);
    
    	@Update("update miaosha_user set password = #{password} where id = #{id}")
    	public void update(MiaoshaUser toBeUpdate);
    }

## 2.5 JSR303参数检验 ##

### **2.5.1 引入依赖** ###

<dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-validation</artifactId>
    </dependency>

public class LoginVo {
    	
    	@NotNull
    	@IsMobile
    	private String mobile;
    	
    	@NotNull
    	@Length(min=32)
    	private String password;
    	......
    }

@Controller
    @RequestMapping("/login")
    public class LoginController {
    
        ...
        
        @RequestMapping("/do_login")
        @ResponseBody
        public Result<String> doLogin(HttpServletResponse response, @Valid LoginVo loginVo) {
           ...
        }
    }

### **2.5.2 自定义Validator** ###

**IsMobile.java**

@Target({ METHOD, FIELD, ANNOTATION_TYPE, CONSTRUCTOR, PARAMETER })
    @Retention(RUNTIME)
    @Documented
    @Constraint(validatedBy = {IsMobileValidator.class })
    public @interface  IsMobile {
    	
    	boolean required() default true;
    	
    	String message() default "手机号码格式错误";
    
    	Class<?>[] groups() default { };
    
    	Class<? extends Payload>[] payload() default { };
    }

**IsMobileValidator.java**

public class IsMobileValidator implements ConstraintValidator<IsMobile, String> {
    
    	private boolean required = false;
    	
    	public void initialize(IsMobile constraintAnnotation) {
    		required = constraintAnnotation.required();
    	}
    
    	public boolean isValid(String value, ConstraintValidatorContext context) {
    		if(required) {
    			return ValidatorUtil.isMobile(value);
    		}else {
    			if(StringUtils.isEmpty(value)) {
    				return true;
    			}else {
    				return ValidatorUtil.isMobile(value);
    			}
    		}
    	}
    }

## 2.6 全局异常处理器 ##

**GlobalException.java**

public class GlobalException extends RuntimeException{
    
    	private static final long serialVersionUID = 1L;
    	
    	private CodeMsg cm;
    	
    	public GlobalException(CodeMsg cm) {
    		super(cm.toString());
    		this.cm = cm;
    	}
    
    	public CodeMsg getCm() {
    		return cm;
    	}
    }

**GlobalExceptionHandler.java**

@ControllerAdvice
    @ResponseBody
    public class GlobalExceptionHandler {
    	@ExceptionHandler(value=Exception.class)
    	public Result<String> exceptionHandler(HttpServletRequest request, Exception e){
    		e.printStackTrace();
    		if(e instanceof GlobalException) {
    			GlobalException ex = (GlobalException)e;
    			return Result.error(ex.getCm());
    		}else if(e instanceof BindException) {
    			BindException ex = (BindException)e;
    			List<ObjectError> errors = ex.getAllErrors();
    			ObjectError error = errors.get(0);
    			String msg = error.getDefaultMessage();
    			return Result.error(CodeMsg.BIND_ERROR.fillArgs(msg));
    		}else {
    			return Result.error(CodeMsg.SERVER_ERROR);
    		}
    	}
    }

## 2.7 分布式Session ##

假设一个项目部署在一个服务器集群中，而负载均衡服务SLB基于服务器集群之上，为客户端的请求分配服务器。同一个用户发送的不同请求是会落在不同的服务器上，那么不同服务器怎样识别同一个用户的session？

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d5ZHlkMTEw_size_16_color_FFFFFF_t_70 6][]

方案一：进行session同步，实现起来复杂。

方案二：使用token。用户登录成功时，服务器会为用户生成一个token（使用UUID来生成），然后写入cookie中，再传递给客户端。客户端发送请求时，会在cookie中上传token，服务器端根据token获取session信息。

（由于SessionID是容器生成的，如果是多台tomcat就会有多个SessionID，所以不直接使用SessionID去实现）

**MiaoshaUserService.java**

@Service
    public class MiaoshaUserService {
    		
    	public static final String COOKI_NAME_TOKEN = "token";
    	
    	@Autowired
    	MiaoshaUserDao miaoshaUserDao;
    	...
    	public MiaoshaUser getByToken(HttpServletResponse response, String token) {
    		if(StringUtils.isEmpty(token)) {
    			return null;
    		}
    		MiaoshaUser user = redisService.get(MiaoshaUserKey.token, token, MiaoshaUser.class);
    		//延长有效期
    		if(user != null) {
    			addCookie(response, token, user);
    		}
    		return user;
    	}
    	
    	public String login(HttpServletResponse response, LoginVo loginVo) {
    		...
    		//用户登录成功后，生成一个token，写入cookie
    		String token = UUIDUtil.uuid();
    		addCookie(response, token, user);
    		return token;
    	}
    	
    	private void addCookie(HttpServletResponse response, String token, MiaoshaUser user) {
            //用户与token一起写入缓存
    		redisService.set(MiaoshaUserKey.token, token, user);
    		Cookie cookie = new Cookie(COOKI_NAME_TOKEN, token);
    		cookie.setMaxAge(MiaoshaUserKey.token.expireSeconds());
    		cookie.setPath("/");
    		response.addCookie(cookie);
    	}
    }

**MiaoshaUserKey.java**

public class MiaoshaUserKey extends BasePrefix{
    
    	public static final int TOKEN_EXPIRE = 3600*24 * 2;
    	private String prefix ;
    	private MiaoshaUserKey(int expireSeconds, String prefix) {
    		super(expireSeconds, prefix);
    		this.prefix = prefix;
    	}
    	public static MiaoshaUserKey token = new MiaoshaUserKey(TOKEN_EXPIRE, "tk");
    	
    	public static MiaoshaUserKey getById = new MiaoshaUserKey(0, "id");
    	
    	public MiaoshaUserKey withExpire(int seconds) {
    		return new MiaoshaUserKey(seconds, prefix);
    	}
    }

**RedisService.java**

@Service
    public class RedisService {
    	
    	@Autowired
    	JedisPool jedisPool;
    	
    	/**
    	 * 获取当个对象
    	 * */
    	public <T> T get(KeyPrefix prefix, String key,  Class<T> clazz) {
    		 Jedis jedis = null;
    		 try {
    			 jedis =  jedisPool.getResource();
    			 //生成真正的key
    			 String realKey  = prefix.getPrefix() + key;
    			 String  str = jedis.get(realKey);
    			 T t =  stringToBean(str, clazz);
    			 return t;
    		 }finally {
    			  returnToPool(jedis);
    		 }
    	}
    	/**
    	 * 设置对象
    	 * */
    	public <T> boolean set(KeyPrefix prefix, String key,  T value) {
    		 Jedis jedis = null;
    		 try {
    			 jedis =  jedisPool.getResource();
    			 String str = beanToString(value);
    			 if(str == null || str.length() <= 0) {
    				 return false;
    			 }
    			//生成真正的key
    			 String realKey  = prefix.getPrefix() + key;
    			 int seconds =  prefix.expireSeconds();
    			 if(seconds <= 0) {
    				 jedis.set(realKey, str);
    			 }else {
    				 jedis.setex(realKey, seconds, str);
    			 }
    			 return true;
    		 }finally {
    			  returnToPool(jedis);
    		 }
    	}
    }

**KeyPrefix.java**

public interface KeyPrefix {	
    	public int expireSeconds();
    	public String getPrefix();
    }

# 3 秒杀功能开发及管理后台 #

## 3.1 数据库设计 ##

## ![20190215104132977.png][] ##

扩充秒杀商品表，而不直接在商品表中添加字段标识，后期有各种活动时，各种修改商品表，不便于扩展。

**goods**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d5ZHlkMTEw_size_16_color_FFFFFF_t_70 7][]

**seckill\_goods**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d5ZHlkMTEw_size_16_color_FFFFFF_t_70 8][]

**order\_info**

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3d5ZHlkMTEw_size_16_color_FFFFFF_t_70 9][]

**seckill\_order**

![20190503134619114.png][]

哪个用户秒杀了哪个商品。

数据表中的id很少用自带的自增，很容易被人从1开始遍历。一般使用snowflake算法。

## 3.2 商品列表页 ##

**goods\_list.html**

<!DOCTYPE HTML>
    <html xmlns:th="http://www.thymeleaf.org">
    <head>
    ...
    </head>
    <body>
    <div class="panel panel-default" style="height:100%;background-color:rgba(222,222,222,0.8)">
      <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_detail.htm?goodsId='+${goods.id}">详情</a></td>  
         </tr>  
      </table>
    </div>
    </body>
    </html>

GoodsController.java

@RequestMapping(value="/to_list")
    public String list(HttpServletRequest request, HttpServletResponse response, Model model,MiaoshaUser user) {
        model.addAttribute("user", user);
        List<GoodsVo> goodsList = goodsService.listGoodsVo();
        model.addAttribute("goodsList", goodsList);
        return render(request, response, model, "goods_list", GoodsKey.getGoodsList, "");
    }

**GoodsDao.java**

@Select("select g.*,mg.stock_count, mg.start_date, mg.end_date,mg.miaosha_price from miaosha_goods mg left join goods g on mg.goods_id = g.id")
    public List<GoodsVo> listGoodsVo();

## 3.3 商品详情页 ##

**goods\_detail.html**

<!DOCTYPE HTML>
    <html xmlns:th="http://www.thymeleaf.org">
    <head>
    ...
    </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>

GoodsController.java

@RequestMapping(value="/detail/{goodsId}")
    @ResponseBody
    public Result<GoodsDetailVo> detail(HttpServletRequest request, HttpServletResponse response, Model model,MiaoshaUser user,
        		@PathVariable("goodsId")long goodsId) {
        	GoodsVo goods = goodsService.getGoodsVoByGoodsId(goodsId);
            //秒杀的开始时间
        	long startAt = goods.getStartDate().getTime();
            //秒杀的结束时间
        	long endAt = goods.getEndDate().getTime();
        	long now = System.currentTimeMillis();
        	int miaoshaStatus = 0;
        	int remainSeconds = 0;
        	if(now < startAt ) {//秒杀还没开始，倒计时
        		miaoshaStatus = 0;
        		remainSeconds = (int)((startAt - now )/1000);
        	}else  if(now > endAt){//秒杀已经结束
        		miaoshaStatus = 2;
        		remainSeconds = -1;
        	}else {//秒杀进行中
        		miaoshaStatus = 1;
        		remainSeconds = 0;
        	}
        	GoodsDetailVo vo = new GoodsDetailVo();
        	vo.setGoods(goods);
        	vo.setUser(user);
        	vo.setRemainSeconds(remainSeconds);
        	vo.setMiaoshaStatus(miaoshaStatus);
        	return Result.success(vo);
        }

**GoodsDao.java**

@Select("select g.*,mg.stock_count, mg.start_date, mg.end_date,mg.miaosha_price from miaosha_goods mg left join goods g on mg.goods_id = g.id where g.id = #{goodsId}")
    public GoodsVo getGoodsVoByGoodsId(@Param("goodsId")long goodsId);

## 3.4 秒杀功能实现 ##

**goods\_detail.html（提交要秒杀的商品的id）**

MiaoshaController.java

//判断库存
    GoodsVo goods = goodsService.getGoodsVoByGoodsId(goodsId);//10个商品，req1 req2
    int stock = goods.getStockCount();
    if(stock <= 0) {
        return Result.error(CodeMsg.MIAO_SHA_OVER);
    }
    //判断是否已经秒杀到了
    MiaoshaOrder order = orderService.getMiaoshaOrderByUserIdGoodsId(user.getId(), goodsId);
    if(order != null) {
        return Result.error(CodeMsg.REPEATE_MIAOSHA);
    }
    //减库存 下订单 写入秒杀订单
    OrderInfo orderInfo = miaoshaService.miaosha(user, goods);
    return Result.success(orderInfo);

## 3.5 订单详情页 ##

**order\_detail.htm**

<!DOCTYPE HTML>
    <html>
    <head>
        <style type="text/css">
            html,body{
                height:100%;
                width:100%;
            }
            body{
                background:url('/img/bg2.jpg') no-repeat;
                background-size:100% 100%;
            }
            #goodslist td{
                border-top:1px solid #39503f61;
            }
        </style>
    </head>
    <body>
    <div class="panel panel-default"  style="height:100%;background-color:rgba(222,222,222,0.8)">
      <div class="panel-heading">秒杀订单详情</div>
      <table class="table" id="goodslist">
            <tr>  
            <td>商品名称</td>  
            <td colspan="3" id="goodsName"></td> 
         </tr>  
         <tr>  
            <td>商品图片</td>  
            <td colspan="2"><img  id="goodsImg" width="200" height="200" /></td>  
         </tr>
          <tr>  
            <td>订单价格</td>  
            <td colspan="2"  id="orderPrice"></td>  
         </tr>
         <tr>
         		<td>下单时间</td>  
            	<td id="createDate" colspan="2"></td>  
         </tr>
         <tr>
         	<td>订单状态</td>  
            <td id="orderStatus">
            </td>  
            <td>
            	<button class="btn btn-primary btn-block" type="submit" id="payButton">立即支付</button>
            </td>
         </tr>
          <tr>
         		<td>收货人</td>  
            	<td colspan="2">XXX  18812341234</td>  
         </tr>
         <tr>
         		<td>收货地址</td>  
            	<td colspan="2">北京市昌平区回龙观龙博一区</td>  
         </tr>
      </table>
    </div>
    </body>
    </html>
    <script>
    function render(detail){
    	var goods = detail.goods;
    	var order = detail.order;
    	$("#goodsName").text(goods.goodsName);
    	$("#goodsImg").attr("src", goods.goodsImg);
    	$("#orderPrice").text(order.goodsPrice);
    	$("#createDate").text(new Date(order.createDate).format("yyyy-MM-dd hh:mm:ss"));
    	var status = "";
    	if(order.status == 0){
    		status = "未支付"
    	}else if(order.status == 1){
    		status = "待发货";
    	}
    	$("#orderStatus").text(status);
    	
    }
    
    $(function(){
    	getOrderDetail();
    })
    
    function getOrderDetail(){
    	var orderId = g_getQueryString("orderId");
    	$.ajax({
    		url:"/order/detail",
    		type:"GET",
    		data:{
    			orderId:orderId
    		},
    		success:function(data){
    			if(data.code == 0){
    				render(data.data);
    			}else{
    				layer.msg(data.msg);
    			}
    		},
    		error:function(){
    			layer.msg("客户端请求有误");
    		}
    	});
    }
    </script>

OrderController.java

@RequestMapping("/detail")
     @ResponseBody
     public Result<OrderDetailVo> info(Model model,MiaoshaUser user,
        		@RequestParam("orderId") long orderId) {
        	if(user == null) {
        		return Result.error(CodeMsg.SESSION_ERROR);
        	}
        	OrderInfo order = orderService.getOrderById(orderId);
        	if(order == null) {
        		return Result.error(CodeMsg.ORDER_NOT_EXIST);
        	}
        	long goodsId = order.getGoodsId();
        	GoodsVo goods = goodsService.getGoodsVoByGoodsId(goodsId);
        	OrderDetailVo vo = new OrderDetailVo();
        	vo.setOrder(order);
        	vo.setGoods(goods);
        	return Result.success(vo);
    }

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[Spring Boot _]: https://www.shiyanlou.com/courses/1152
[Link 1]: http://www.mybatis.org/spring-boot-starter/mybatis-spring-boot-autoconfigure/
[Redis]: https://www.shiyanlou.com/courses/106
[Link 2]: https://redis.io/
[Link 3]: https://redis.io/download
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[jQuery Validate]: http://www.runoob.com/jquery/jquery-plugin-validate.html
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