分布式使用Redis实现数据库对象自增主键ID

@Component("redisUtils")
@RequiredArgsConstructor
@Slf4j
public class RedisUtils implements InitializingBean {
    private final StringRedisTemplate stringRedisTemplate;
    private static RedisUtils redisUtils;

    @Override
    public void afterPropertiesSet() {
        redisUtils = this;
    }

    /**
     * 获取自增ID
     */
    public static <T> Integer getIncr(Class<T> tClass) {
        try {
            String key = tClass.getName();
            Long increment = redisUtils.stringRedisTemplate.opsForValue().increment(key, 1);
            return Math.toIntExact(increment);
        } catch (Exception e) {
            e.printStackTrace();
            throw new RedisSystemException(e.getMessage(), e);
        }
    }

    /**
     * 获取自增ID，指定递增长度，用于批量创建对象时，只请求一次Redis
     * 如批量创建五个对象，delta等于5
     */
    public static <T> Integer getIncr(Class<T> tClass, int delta) {
        try {
            String key = tClass.getName();
            Long increment = redisUtils.stringRedisTemplate.opsForValue().increment(key, delta);
            return Math.toIntExact(increment);
        } catch (Exception e) {
            e.printStackTrace();
            throw new RedisSystemException(e.getMessage(), e);
        }
    }

    /**
     * 缓存预热，用于项目启动时初始化Redis中各个表的最大ID
     */
    public static <T> long incrPreheat(Class<T> tClass, Long maxValue) {
        if (maxValue == null) {
            maxValue = 0L;
        }
        if (maxValue < 0) {
            //异常抛出，预热的初始值不能小于0
        }
        Integer incr = getIncr(tClass);
        if (maxValue <= incr) {
            return incr;
        }
        return getIncr(tClass, (int) (maxValue - incr));
    }
}

/**
 * 缓存预热
 *
 * @author hxy
 */
@Component
@DependsOn("redisUtils")
@RequiredArgsConstructor
public class RedisInit {

    private final UserMapper userMapper;

    /**
     * 获取每一张表中当前的最大ID，然后预热到redis中
     */
    @PostConstruct
    public void init() {
        RedisUtils.incrPreheat(UserModel.class, userMapper.maxId());
    }
}

@Getter
@Setter
public class UserModel {

    private Integer id;

    private String name;

    private Integer age;

    private String tel;

    public UserModel() {
    }

    /**
     * 提供一个能够生成自增ID的有参构造，需要生成自增ID时调用
     */
    public UserModel(boolean autoId) {
        if (autoId) {
            this.id = RedisUtils.getIncr(UserModel.class);
        }
    }
}

@Service
@RequiredArgsConstructor
public class UserServiceImpl {

    private final UserMapper userMapper;

    public void batchAddUser(){
        int addNumber = 10;
        //提前生成自定跨度的ID，比如之前最大ID是6，获取后得到的incr是16
        Integer incr = RedisUtils.getIncr(UserModel.class, addNumber);
        List<UserModel> userModels = new ArrayList<>();
        for (int i = 0; i < addNumber; i++) {
            UserModel userModel = new UserModel();
            //每一个主键ID依次递减使用
            userModel.setId(incr--);
            userModels.add(userModel);
        }
        userMapper.insertBatch(userModels);
    }
}