redis做分布式id

深碍√TFBOYSˉ_ 2021-11-17 06:52 206阅读 0赞

速度很快，一万个才半秒  
最安全，比随机数安全多了  
长度合适，不想随机数很长  
16位id，比如2019073000000041，前八位日期，后八位redis计数器，格式化成八位长数字字符串

策略：  
每个表作为hash的key，日期作为hashKey，计数器作为hash值  
每天日期变更，使用新的hashKey，  
之所以不覆盖旧的日期key，为了容错。假设集群下不同机器的时间有误差，可能这个机器是今天，另外机器是昨天。

定时任务删除前天的key，昨天的保留，适当冗余。

@Component
    public class RedisId {
        private String DISTRIBUTE_ID = "DISTRIBUTE_ID:";
        private String date = LocalDate.now().toString().replace("-", "");
    
        @Autowired
        private RedisTemplate<String, String> redisTemplate;
        @Autowired
        private RedisLockRegistry redisLockRegistry;
    
        @Scheduled(cron = "0 0 0 0/1 * *")
        public void init() {
            deleteOldDays();
    
        }
    
        public void deleteOldDays() {
            //置换当前日期
            date = LocalDate.now().toString().replace("-", "");
    
            //删除前天的id
            Lock lock = redisLockRegistry.obtain("DELETE_OLD_DAYS");
            try {
                boolean b = lock.tryLock(1, TimeUnit.MINUTES);
                if (!b) {
                    return;
                }
                Set<String> keys = redisTemplate.keys(DISTRIBUTE_ID + "*");
                if (keys == null || keys.size() == 0) {
                    return;
                }
    
                String yesterday = LocalDate.now().minusDays(1).toString().replace("-", "");
                keys.forEach(key -> {
                    Set<Object> daySet = redisTemplate.opsForHash().keys(key);
                    if (daySet != null && daySet.size() > 0) {
                        daySet.forEach(day -> {
                            if (day.toString().compareTo(yesterday) < 0) {
                                redisTemplate.opsForHash().delete(key, day);
                            }
                        });
                    }
                });
            } catch (InterruptedException e) {
                e.printStackTrace();
            } finally {
                lock.unlock();
            }
        }
    
        public String getId() {
            return doGetId("COMMON");
        }
    
        public String getMachineId() {
            return doGetId("MACHINE");
        }
    
        private String doGetId(String key) {
            Long increment = redisTemplate.opsForHash().increment(DISTRIBUTE_ID + key, date, 1);
            return date + String.format("%08d", increment);
        }
    
    }

每个表使用一个方法，提高并发性

使用举例

@RestController
    @RequestMapping("/redisId")
    public class RedisIdController {
    
        @Autowired
        private RedisId redisId;
    
        @RequestMapping("/commonId")
        public String commonId(){
            return redisId.getId();
        }
    
        @RequestMapping("/machineId")
        public String machineId(){
            return redisId.getMachineId();
        }
    
        @RequestMapping("/deleteOldDays")
        public String deleteOldDays(){
            redisId.deleteOldDays();
            return "deleteOldDays ok";
        }
    
        //一万个id才半秒，速度很快
        @RequestMapping("/manyId")
        public String manyId(){
            LocalDateTime now = LocalDateTime.now();
            for (int i = 0; i < 10000; i++) {
                redisId.getId();
            }
            System.out.println(Duration.between(now, LocalDateTime.now()));//PT0.511S
            return "manyId ok";
        }
    
    }