how can I cache list of object in spring?

Question

I have an method called getUserById

@Cacheable(value = "Account", key = "#accountId")
public Account getUserById(Long accountId) {

and another method called getUserByIds

@Cacheable(?????)
public List<Account> getUserByIds(List<Long> accountIds) {

how can I cache all account by account id? thanks

You can store the whole result of the method not the individual users (as in the second approach). Also you are probably using an ORM like hibernate and I would strongly suggest to use the 2nd level caching features of that framework instead of this way of caching then. — M. Deinum, Aug 17 '18 at 07:07

score 1 · Answer 1 · answered Jun 07 '22 at 16:31

Actually you don't need to specify key for @Cacheable at all

In my case I needed to read from repo a collection and store it in-memory for the following iterations through a list.

@Cacheable("users")
public List<RegionPercentage> getUserByIds(List<Long> accountIds) {
    return repository.getUsers();
}

Using this method my method returns list from cache every time it is NOT empty INSTEAD of invoking repository.

Thus, for the sake of updating cache I managed to clear it automatically using cron (in my case every 30 seconds to see the difference)

@Scheduled(cron = "0,30 * * * * ?")
@CacheEvict(value = "users", allEntries = true)
public void deleteCache() {
  // this method can be empty
}

Do not forget to set up @EnableCaching in main class of your Spring Boot Application

1 Answers1