java 43 lines · 7 steps

How Spring cache annotations keep data fresh

A Spring service uses @Cacheable and @CacheEvict to serve reads from cache while invalidating stale entries on writes.

Explained by highlit

Spring Intermediate caching cache-invalidation dependency-injection spel transactions

1@Service
2public class ProductCatalogService {
3 
  private final ProductRepository productRepository;
  private final PricingClient pricingClient;
6 
  public ProductCatalogService(ProductRepository productRepository, PricingClient pricingClient) {
      this.productRepository = productRepository;
      this.pricingClient = pricingClient;
  }
11 
  @Cacheable(cacheNames = "products", key = "#productId")
  public ProductView getProduct(long productId) {
      Product product = productRepository.findById(productId)
              .orElseThrow(() -> new ProductNotFoundException(productId));
      Money price = pricingClient.resolveCurrentPrice(product.getSku());
      return ProductView.from(product, price);
  }
19 
  @Cacheable(cacheNames = "productsByCategory", key = "#category", unless = "#result.isEmpty()")
  public List<ProductView> getProductsByCategory(String category) {
      return productRepository.findByCategory(category).stream()
              .map(p -> ProductView.from(p, pricingClient.resolveCurrentPrice(p.getSku())))
              .toList();
  }
26 
  @Caching(evict = {
          @CacheEvict(cacheNames = "products", key = "#result.id"),
          @CacheEvict(cacheNames = "productsByCategory", key = "#command.category")
  })
  @Transactional
  public Product updateProduct(UpdateProductCommand command) {
      Product product = productRepository.findById(command.productId())
              .orElseThrow(() -> new ProductNotFoundException(command.productId()));
      product.rename(command.name());
      product.recategorize(command.category());
      return productRepository.save(product);
  }
39 
  @CacheEvict(cacheNames = {"products", "productsByCategory"}, allEntries = true)
  public void invalidateAll() {
  }
43}

01 / 01

STEP 01

Walkthrough

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Three takeaways

1Cache reads with @Cacheable and evict on writes so callers never see stale product data.
2SpEL expressions like key and unless let you shape cache keys and skip caching empty results.
3Grouping multiple @CacheEvict under @Caching keeps two related caches consistent from a single write.

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