前言
该篇主要实现秒杀业务层，秒杀业务逻辑里主要包括暴露秒杀接口地址、实现秒杀业务逻辑。同时声明了三个业务类：Exposer、SeckillExecution、SeckillResult。 Exposer主要用来实现暴露接口时一个md5的加密，防止用户在客户端篡改数据。根据seckillid生成md5，提交秒杀请求时会根据这个md5和seckillid比对是否是合法的请求。SeckillExecution主要封装秒杀时的返回值。
SeckillExecution有2个属性，state、stateinfo，这里我没有封装枚举值，还是用整型和字符串给客户端传值，在Service里看着也直观些。
准备工作
1、spring-service.xml
业务逻辑里的关键是开启事务，这里推荐用注解的方式实现。
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:context="http://www.springframework.org/schema/context" xmlns:tx="http://www.springframework.org/schema/tx" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd"> <!--1、注解包扫描--> <context:component-scan base-package="com.seckill.service"/> <!--2、配置声明式事务--> <bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager"> <!--注入数据库--> <property name="dataSource" ref="dataSource"/> </bean> <!--3、配置基于注解的声明式事务--> <tx:annotation-driven transaction-manager="transactionManager"/> </beans>
实现秒杀业务
秒杀相关的关键方法就是最后两个方法，一个是对外暴漏秒杀地址，一个是秒杀方法。
public interface SeckillService {
List<Seckill> getSeckillList();
Seckill getById(long seckillId);
/**对外暴漏秒杀接口**/
Exposer exposeSeckillUrl(long seckillId);
/**
* 执行秒杀操作，有可能成功，有可能失败，所以这里我们抛出自自定义异常
* ***/
SeckillExecution executeSeckill(long seckillId,long phone,String md5) throws SeckillException,
RepeatKillException,
SeckillCloseException;
}
@Service
public class SeckillServiceImpl implements SeckillService {
/***
* 秒杀行为的枚举放在这里说明
* 1、 秒杀成功
* 0、 秒杀结束
* -1、重复秒杀
* -2、系统异常
* -3、数据篡改
* ***/
private Logger logger = LoggerFactory.getLogger(this.getClass());
@Autowired
SeckillDao seckillDao;
@Autowired
SuccessKillDao successKillDao;
private String salt = "zhangfei";
@Override
public List<Seckill> getSeckillList() {
return seckillDao.queryAll(0, 100);
}
@Override
public Seckill getById(long seckillId) {
return seckillDao.queryById(seckillId);
}
@Override
public Exposer exposeSeckillUrl(long seckillId) {
Seckill seckill = getById(seckillId);
Date startTime = seckill.getStartTime();
Date endTime = seckill.getEndTime();
Date now = new Date();
if (now.getTime() < startTime.getTime() || now.getTime() > endTime.getTime()) {
return new Exposer(false, seckillId, startTime.getTime(), endTime.getTime(), now.getTime());
}
String md5 = getMd5(seckillId);
return new Exposer(true, md5, seckillId);
}
@Override
@Transactional
public SeckillExecution executeSeckill(long seckillId, long phone, String md5)
throws SeckillException,RepeatKillException,SeckillCloseException {
if (md5 == null || !md5.equals(getMd5(seckillId))) {
throw new SeckillException("非法请求");
}
Date now = new Date();
try {
int insertCount = successKillDao.insertSuccessKilled(seckillId, phone);
if (insertCount <= 0) {
throw new RepeatKillException("重复秒杀");
} else {
int updateCount = seckillDao.reduceNumber(seckillId, now);
if (updateCount <= 0) {
throw new SeckillCloseException("秒杀已关闭");
} else {
//秒杀成功，可以把秒杀详情和商品详情实体返回
SuccessKilled successKilled = successKillDao.queryByIdWithSeckill(seckillId, phone);
return new SeckillExecution(seckillId, 1, "秒杀成功", successKilled);
}
}
} catch (SeckillCloseException e) {
throw e;
} catch (RepeatKillException e1) {
throw e1;
} catch (SeckillException e2) {
logger.error(e2.getMessage(), e2);
throw new SeckillException("Unkonwn error:" + e2.getMessage());
}
}
private String getMd5(long seckillId) {
String base = seckillId + "/" + salt;
String md5 = DigestUtils.md5DigestAsHex(base.getBytes());
return md5;
}
}