Null key returned for cache operation (maybe you are using named params on classes without debug info?) Builder（解决Null key returned for cache operation）

  @Cacheable(cacheNames = "demoCache", key = "#id")

    User getUserById(Integer id);

解决: key = "#id"  改成: key = "'_' + #id"

  @Cacheable(cacheNames = "demoCache", key = "'_' + #id")

    User getUserById(Integer id);