eckillEvent, seq, objs) -> {
seckillEvent.setSeckillId((Long) objs[0]);
seckillEvent.setUserId((Long) objs[1]);
};
private final RingBuffer<SecondKillEvent> ringBuffer;
public SecondKillEventProducer(RingBuffer<SecondKillEvent> ringBuffer){
this.ringBuffer = ringBuffer;
}
public void secondKill(long seckillId, long userId){
this.ringBuffer.publishEvent(translator, seckillId, userId);
}
}
// 消费者(秒杀处理器)
@Slf4j
public class SecondKillEventConsumer implements EventHandler<SecondKillEvent> {
private SecondKillService secondKillService = (SecondKillService) SpringUtil.getBean("secondKillService");
@Override
public void onEvent(SecondKillEvent seckillEvent, long seq, boolean bool) {
Result result = secondKillService.startSecondKillByAop(seckillEvent.getSeckillId(), seckillEvent.getUserId());
if(result.equals(Result.ok(SecondKillStateEnum.SUCCESS))){
log.info("用户:{}{}",seckillEvent.getUserId(),"秒杀成功");
}
}
}
public class DisruptorUtil {
static Disruptor<SecondKillEvent> disruptor;
static{
SecondKillEventFactory factory = new SecondKillEventFactory();
int ringBufferSize = 1024;
ThreadFactory threadFactory = runnable -> new Thread(runnable);
disruptor = new Disruptor<>(factory, ringBufferSize, threadFactory);
disruptor.handleEventsWith(new SecondKillEventConsumer());
disruptor.start();
}
public static void producer(SecondKillEvent kill){
RingBuffer<SecondKillEvent> ringBuffer = disruptor.getRingBuffer();
SecondKillEventProducer producer = new SecondKillEventProducer(ringBuffer);
producer.secondKill(kill.getSeckillId(),kill.getUserId());
}
}
@ApiOperation(value="秒杀实现方式七——Disruptor队列")
@PostMapping("/start/disruptor")
public Result startDisruptor(long skgId){
try {
log.info("开始秒杀方式七...");
final long userId = (int) (new Random().nextDouble() * (99999 - 10000 + 1)) + 10000;
SecondKillEvent kill = new SecondKillEvent();
kill.setSeckillId(skgId);
kill.setUserId(userId);
DisruptorUtil.producer(kill);
} catch (Exception e) {
e.printStackTrace();
}
return Result.ok();
}
经过测试,发现使用Disruptor队列队列,与自定义队列有着同样的问题,也会出现超卖的情况,但效率有所提高。
4. 小结
对于上面七种实现并发的方式,做一下总结:
- 一、二方式是在代码中利用锁和事务的方式解决了并发问题,主要解决的是锁要加载事务之前
- 三、四、五方式主要是数据库的锁来解决并发问题,方式三是利用for upate对表加行锁,方式四是利用update来对表加锁,方式五是通过增加version字段来控制数据库的更新操作,方式五的效果最差
- 六、七方式是通过队列来解决并发问题,这里需要特别注意的是,在代码中不能通过throw抛异常,否则消费线程会终止,而且由于进队和出队存在时间间隙,会导致商品少卖
上面所有的情况都经过代码测试,测试分一下三种情况:
- 并发数1000,商品数100
- 并发数1000,商品数1000
- 并发数2000,商品数1000
思考:分布式情况下如何解决并发问题呢?下次继续试验。
版权声明:本文为CSDN博主「止步前行」的原创文章,遵循CC 4.0 BY-SA版权协议,转载请附上原文出处链接及本声明。原文链接:https://blog.csdn.net/zxd1435513775/article/details/122643285
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