jseckill源码解析

@Override
    public Exposer exportSeckillUrl(long seckillId) {
        // 优化点:缓存优化:超时的基础上维护一致性
        //1.访问Redis
        Seckill seckill = redisDAO.getSeckill(seckillId);
        if (seckill == null) {
            //2.访问数据库
            seckill = seckillDAO.queryById(seckillId);
            if (seckill == null) {
                return new Exposer(false, seckillId);
            } else {
                //3.存入Redis
                redisDAO.putSeckill(seckill);
            }
        }

        Date startTime = seckill.getStartTime();
        Date endTime = seckill.getEndTime();
        //系统当前时间
        Date nowTime = new Date();
        if (nowTime.getTime() < startTime.getTime()
                || nowTime.getTime() > endTime.getTime()) {
            return new Exposer(false, seckillId, nowTime.getTime(), startTime.getTime(),
                    endTime.getTime());
        }
        //转化特定字符串的过程，不可逆
        String md5 = getMD5(seckillId);
        return new Exposer(true, md5, seckillId);
    }

package com.liushaoming.jseckill.backend.service.impl;

import com.google.common.util.concurrent.RateLimiter;
import com.liushaoming.jseckill.backend.service.AccessLimitService;
import org.springframework.stereotype.Service;

/**
 * 秒杀前的限流.
 * 使用了Google guava的RateLimiter
 */
@Service
public class AccessLimitServiceImpl implements AccessLimitService {
    /**
     * 每秒钟只发出10个令牌，拿到令牌的请求才可以进入秒杀过程
     */
    private RateLimiter seckillRateLimiter = RateLimiter.create(10);

    /**
     * 尝试获取令牌
     * @return
     */
    @Override
    public boolean tryAcquireSeckill() {
        return seckillRateLimiter.tryAcquire();
    }
}

@Override
@Transactional
/**
 * 执行秒杀
 */
public SeckillExecution executeSeckill(long seckillId, long userPhone, String md5) throws SeckillException {
    if (accessLimitService.tryAcquireSeckill()) {   // 如果没有被限流器限制，则执行秒杀处理
        return updateStock(seckillId, userPhone, md5);
    } else {    //如果被限流器限制，直接抛出访问限制的异常
        logger.info("--->ACCESS_LIMITED-->seckillId={},userPhone={}", seckillId, userPhone);
        throw new SeckillException(SeckillStateEnum.ACCESS_LIMIT);
    }
}

@Override
    @Transactional
    /**
     * 先插入秒杀记录再减库存
     */
    public SeckillExecution executeSeckill(long seckillId, long userPhone, String md5)
            throws SeckillException, RepeatKillException, SeckillCloseException {
        if (md5 == null || !md5.equals(getMD5(seckillId))) {
            logger.info("seckill data rewrite!!!. seckillId={},userPhone={}", seckillId, userPhone);
            throw new SeckillException("seckill data rewrite");
        }
        //执行秒杀逻辑:减库存 + 记录购买行为
        Date nowTime = new Date();

        try {
            //插入秒杀记录(记录购买行为)
            int insertCount = successKilledDAO.insertSuccessKilled(seckillId, userPhone);
            //唯一:seckillId,userPhone
            if (insertCount <= 0) {
                //重复秒杀
                logger.info("seckill repeated. seckillId={},userPhone={}", seckillId, userPhone);
                throw new RepeatKillException("seckill repeated");
            } else {
                //减库存,热点商品竞争
                // reduceNumber是update操作，开启作用在表seckill上的行锁
                int updateCount = seckillDAO.reduceNumber(seckillId, nowTime);
                if (updateCount <= 0) {
                    //没有更新到记录，秒杀结束,rollback
                    throw new SeckillCloseException("seckill is closed");
                } else {
                    //秒杀成功 commit
                    SuccessKilled payOrder = successKilledDAO.queryByIdWithSeckill(seckillId, userPhone);
                    logger.info("seckill SUCCESS->>>. seckillId={},userPhone={}", seckillId, userPhone);
                    //事务结束，关闭作用在表seckill上的行锁
                    return new SeckillExecution(seckillId, SeckillStateEnum.SUCCESS, payOrder);
                }
            }
        } catch (SeckillCloseException e1) {
            throw e1;
        } catch (RepeatKillException e2) {
            throw e2;
        } catch (Exception e) {
            logger.error(e.getMessage(), e);
            //  所有编译期异常 转化为运行期异常
            throw new SeckillException("seckill inner error:" + e.getMessage());
        }
    }

#Rabbitmq配置
rabbitmq.address-list=192.168.20.3:5672,localhost:5672
rabbitmq.username=myname
rabbitmq.password=somepass
rabbitmq.publisher-confirms=true
rabbitmq.virtual-host=/vh_test
rabbitmq.queue=seckill

rabbitmq.address-list=192.168.20.3:5672,localhost:5672

com.rabbitmq.client.ConnectionFactory#newConnection(List<Address> addrs) throws IOException, TimeoutException {}

@Bean("mqConnectionSeckill")
    public Connection mqConnectionSeckill(@Autowired MQConfigBean mqConfigBean) throws IOException, TimeoutException {
        ConnectionFactory factory = new ConnectionFactory();
        //用户名
        factory.setUsername(username);
        //密码
        factory.setPassword(password);
        //虚拟主机路径（相当于数据库名）
        factory.setVirtualHost(virtualHost);
        //返回连接
        return factory.newConnection(mqConfigBean.getAddressList());
    }