redis用zset做延时消息

素颜马尾好姑娘i 2023-06-15 11:29 10阅读 0赞

把执行时间作为分数，存到zset中。  
定时任务，分数倒序取出第一个，小于当前时间，说明消息可以执行了

## 发送延时消息服务 ##

public Object publishDelayedMsg() { 
            OrderDTO dto = new OrderDTO();
            dto.setId(1);
            dto.setCreateTime(new Date());
            dto.setMoney("12.34");
            dto.setOrderNo("orderNo1");
    
            String s = JSON.toJSONString(dto);
            long executeTime = System.currentTimeMillis() + 60000L;
    
            ZSetOperations<String, String> zSetOperations = redisTemplate.opsForZSet();
            zSetOperations.add(RedisConstant.MQ_ZSET, s, executeTime);
    
            Long size = zSetOperations.size(RedisConstant.MQ_ZSET);
            Set<String> set = new HashSet<>();
            if (size != null && size > 0) { 
                set = zSetOperations.range(RedisConstant.MQ_ZSET, 0, size - 1);
            }
            return set;
        }

controller

//http://localhost:9040/redisZset/publishDelayedMsg
        @GetMapping("publishDelayedMsg")
        public Object publishDelayedMsg() { 
            return redisService.publishDelayedMsg();
        }

## 消费消息服务 ##

定时任务

@TaskLock(RedisConstant.CONSUME_REDIS_ZSET_TASK)
        @Scheduled(cron = "0/10 * * * * ?")
        public void consumeMqZset() { 
            redisService.consumeMqZset();
        }

消费消息

public void consumeMqZset() { 
            ZSetOperations<String, String> zSetOperations = redisTemplate.opsForZSet();
            Set<ZSetOperations.TypedTuple<String>> typedTuples = zSetOperations.reverseRangeByScoreWithScores(RedisConstant.MQ_ZSET, 0, System.currentTimeMillis(), 0, 1);
            if (typedTuples == null || typedTuples.isEmpty()) { 
                return;
            }
    
            ZSetOperations.TypedTuple<String> typedTuple = typedTuples.iterator().next();
    
            Double score = typedTuple.getScore();
            if (score == null) { 
                return;
            }
    
            long l = score.longValue();
            if (l > System.currentTimeMillis()) { 
                return;
            }
    
            String value = typedTuple.getValue();
            OrderDTO dto = JSON.parseObject(value, OrderDTO.class);
            System.out.println(dto);
    
            zSetOperations.remove(RedisConstant.MQ_ZSET, value);
        }

消费完消息后，删除消息

https://github.com/mingwulipo/cloud-demo.git