redis用list做消息队列的实现示例
leftPush消息入队，rightPop对应，消息出队。
rightPop(RedisConstant.MQ_LIST, 0L, TimeUnit.SECONDS)阻塞出队，0表示永久阻塞
生产消息服务
public class RedisService {
@Autowired
private RedisTemplate<String, String> redisTemplate;
public Object publish() {
OrderDTO dto = new OrderDTO();
dto.setId(1);
dto.setCreateTime(new Date());
dto.setMoney(“12.34”);
dto.setOrderNo(“orderNo1”);
String s = JSON.toJSONString(dto);
ListOperations<String, String> listOperations = redisTemplate.opsForList();
//leftPush和rightPop对应，左侧入队，右侧出队
listOperations.leftPush(RedisConstant.MQ_LIST, s);
//由于出队是阻塞读取的，所以上一步入队后，数据立刻就被驱走了，下一步size=0
Long size = listOperations.size(RedisConstant.MQ_LIST);
List<String> list = new ArrayList<>();
if (size != null && size > 0) {
list = listOperations.range(RedisConstant.MQ_LIST, 0, size – 1);
}
return list;
}
}
测试
@RequestMapping(“redisList”)
public class RedisListController {
@Autowired
private RedisService redisService;
@GetMapping(“publish”)
public Object publish() {
return redisService.publish();
}
}
消费消息服务，定时任务
public class RedisConsumeTask {
@Autowired
private RedisService redisService;
@TaskLock(RedisConstant.CONSUME_REDIS_LIST)
@Scheduled(cron = “0/10 * * * * ?”)
public void consumeMqList() {
redisService.consumeMqList();
}
}
@Service
@Slf4j
public class RedisService {
@Autowired
private RedisTemplate<String, String> redisTemplate;
public void consumeMqList() {
ListOperations<String, String> listOperations = redisTemplate.opsForList();
//0时间，表示阻塞永久
//待机一小时后，再次发消息，消费不了了，阻塞有问题啊。还得轮寻啊
//String s = listOperations.rightPop(RedisConstant.MQ_LIST, 0L, TimeUnit.SECONDS);
String s = listOperations.rightPop(RedisConstant.MQ_LIST);
if (s == null) {
return;
}
log.info(“{} = {}”, RedisConstant.MQ_LIST, s);
OrderDTO dto = JSON.parseObject(s, OrderDTO.class);
log.info(“dto = {}”, dto);
}
}
日志
@Aspect
public class TaskLockAop {
@Autowired
private RedisLockRegistry redisLockRegistry;
@Around(“execution(@TaskLock * * (..))”)
public Object taskAround(ProceedingJoinPoint pjp) throws Throwable {
TaskLock taskAnnotation = ((MethodSignature)pjp.getSignature()).getMethod().getAnnotation(TaskLock.class);
String lockKey = taskAnnotation.value();
Lock lock = redisLockRegistry.obtain(lockKey);
try {
lock.tryLock(30L, TimeUnit.SECONDS);
System.out.println(“任务开始, ” + lockKey + “, ” + new Date());
return pjp.proceed();
} finally {
lock.unlock();
System.out.println(“任务结束, ” + lockKey + “, ” + new Date());
}
}
}
测试
http://localhost:9040/redisList/publish
["{“createTime”:1574394538430,“id”:1,“money”:“12.34”,“orderNo”:“orderNo1”}"]
下面一直阻塞，任务开始了，不收到消息，永久不会结束。
阻塞有问题，改用轮询了。
先启动发送消息服务，发送消息。后启动消费消息服务，可以消费消息。这一点，比发布定阅要稳定。
关联项目https://github.com/mingwulipo/cloud-demo.git
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文章标题：redis用list做消息队列的实现示例
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