Two-Level Cache in Spring Boot: Boost Performance with Caffeine & Redis

In high‑performance service architectures, caching is essential. Remote caches such as Redis or MemCache store hot data and only query the database when a cache miss occurs, reducing latency and database load.

When remote caches alone are insufficient, a local cache (e.g., Guava or Caffeine) can be added as a first‑level cache, forming a two‑level cache architecture that further improves response speed.

Advantages and Issues

Local cache resides in JVM memory, providing extremely fast access for data with low change frequency.

Using a local cache reduces network I/O between the application and remote cache ( Redis), decreasing latency.

Data consistency must be handled: updates to the database must also refresh or invalidate both local and remote caches.

In distributed environments, local caches on different nodes need synchronization, often via Redis pub/sub.

Preparation

Add the required dependencies for Caffeine, Spring Boot Redis, and connection pooling:

<dependency>
    <groupId>com.github.ben-manes.caffeine</groupId>
    <artifactId>caffeine</artifactId>
    <version>2.9.2</version>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>
<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-cache</artifactId>
</dependency>
<dependency>
    <groupId>org.apache.commons</groupId>
    <artifactId>commons-pool2</artifactId>
    <version>2.8.1</version>
</dependency>

Configure Redis connection in application.yml:

spring:
  redis:
    host: 127.0.0.1
    port: 6379
    database: 0
    timeout: 10000ms
    lettuce:
      pool:
        max-active: 8
        max-wait: -1ms
        max-idle: 8
        min-idle: 0

V1.0 – Manual Two‑Level Cache

Define a Caffeine bean:

@Configuration
public class CaffeineConfig {
    @Bean
    public Cache<String, Object> caffeineCache() {
        return Caffeine.newBuilder()
                .initialCapacity(128)
                .maximumSize(1024)
                .expireAfterWrite(60, TimeUnit.SECONDS)
                .build();
    }
}

Typical service method without caching:

@Service
@AllArgsConstructor
public class OrderServiceImpl implements OrderService {
    private final OrderMapper orderMapper;

    @Override
    public Order getOrderById(Long id) {
        return orderMapper.selectOne(new LambdaQueryWrapper<Order>().eq(Order::getId, id));
    }

    @Override
    public void updateOrder(Order order) {
        orderMapper.updateById(order);
    }

    @Override
    public void deleteOrder(Long id) {
        orderMapper.deleteById(id);
    }
}

Wrap the method with two‑level cache logic:

public Order getOrderById(Long id) {
    String key = CacheConstant.ORDER + id;
    Order order = (Order) cache.get(key, k -> {
        // 1. Try Redis
        Object obj = redisTemplate.opsForValue().get(k);
        if (obj != null) {
            log.info("get data from redis");
            return obj;
        }
        // 2. Fallback to DB
        log.info("get data from database");
        Order dbOrder = orderMapper.selectOne(new LambdaQueryWrapper<Order>().eq(Order::getId, id));
        redisTemplate.opsForValue().set(k, dbOrder, 120, TimeUnit.SECONDS);
        return dbOrder;
    });
    return order;
}

Update and delete operations manually synchronize both caches:

public void updateOrder(Order order) {
    log.info("update order data");
    String key = CacheConstant.ORDER + order.getId();
    orderMapper.updateById(order);
    redisTemplate.opsForValue().set(key, order, 120, TimeUnit.SECONDS);
    cache.put(key, order);
}

public void deleteOrder(Long id) {
    log.info("delete order");
    orderMapper.deleteById(id);
    String key = CacheConstant.ORDER + id;
    redisTemplate.delete(key);
    cache.invalidate(key);
}

V2.0 – Spring Cache Annotations

Configure a CaffeineCacheManager bean:

@Configuration
public class CacheManagerConfig {
    @Bean
    public CacheManager cacheManager() {
        CaffeineCacheManager manager = new CaffeineCacheManager();
        manager.setCaffeine(Caffeine.newBuilder()
                .initialCapacity(128)
                .maximumSize(1024)
                .expireAfterWrite(60, TimeUnit.SECONDS));
        return manager;
    }
}

Enable Spring caching in the main application class:

@SpringBootApplication
@EnableCaching
public class MallApplication { ... }

Apply annotations to service methods:

@Cacheable(value = "order", key = "#id")
public Order getOrderById(Long id) {
    // only DB logic; Redis handling omitted for brevity
    return orderMapper.selectOne(new LambdaQueryWrapper<Order>().eq(Order::getId, id));
}

@CachePut(cacheNames = "order", key = "#order.id")
public Order updateOrder(Order order) {
    orderMapper.updateById(order);
    redisTemplate.opsForValue().set(CacheConstant.ORDER + order.getId(), order, 120, TimeUnit.SECONDS);
    return order;
}

@CacheEvict(cacheNames = "order", key = "#id")
public void deleteOrder(Long id) {
    orderMapper.deleteById(id);
    redisTemplate.delete(CacheConstant.ORDER + id);
}

With these annotations, Spring automatically handles the local Caffeine cache, while the Redis update is still performed manually.

V3.0 – Custom @DoubleCache Annotation

Define the annotation:

@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface DoubleCache {
    String cacheName();
    String key(); // supports SpringEL
    long l2TimeOut() default 120; // Redis expiration
    CacheType type() default CacheType.FULL; // FULL, PUT, DELETE
}

Enum for cache operation type:

public enum CacheType {
    FULL,   // read‑write
    PUT,    // write only
    DELETE  // delete only
}

Utility to parse SpringEL expressions:

public static String parse(String elString, TreeMap<String, Object> map) {
    elString = String.format("#{%s}", elString);
    ExpressionParser parser = new SpelExpressionParser();
    EvaluationContext context = new StandardEvaluationContext();
    map.forEach(context::setVariable);
    Expression expression = parser.parseExpression(elString, new TemplateParserContext());
    return expression.getValue(context, String.class);
}

Aspect that implements the caching logic:

@Component
@Aspect
@AllArgsConstructor
public class CacheAspect {
    private final Cache cache; // Caffeine
    private final RedisTemplate redisTemplate;

    @Pointcut("@annotation(com.cn.dc.annotation.DoubleCache)")
    public void cacheAspect() {}

    @Around("cacheAspect()")
    public Object doAround(ProceedingJoinPoint point) throws Throwable {
        MethodSignature signature = (MethodSignature) point.getSignature();
        Method method = signature.getMethod();
        String[] paramNames = signature.getParameterNames();
        Object[] args = point.getArgs();
        TreeMap<String, Object> map = new TreeMap<>();
        for (int i = 0; i < paramNames.length; i++) {
            map.put(paramNames[i], args[i]);
        }
        DoubleCache ann = method.getAnnotation(DoubleCache.class);
        String realKey = ann.cacheName() + ":" + ElParser.parse(ann.key(), map);

        // PUT only
        if (ann.type() == CacheType.PUT) {
            Object result = point.proceed();
            redisTemplate.opsForValue().set(realKey, result, ann.l2TimeOut(), TimeUnit.SECONDS);
            cache.put(realKey, result);
            return result;
        }
        // DELETE only
        if (ann.type() == CacheType.DELETE) {
            redisTemplate.delete(realKey);
            cache.invalidate(realKey);
            return point.proceed();
        }
        // FULL (read‑write)
        Object local = cache.getIfPresent(realKey);
        if (local != null) {
            log.info("get data from caffeine");
            return local;
        }
        Object remote = redisTemplate.opsForValue().get(realKey);
        if (remote != null) {
            log.info("get data from redis");
            cache.put(realKey, remote);
            return remote;
        }
        log.info("get data from database");
        Object result = point.proceed();
        if (result != null) {
            redisTemplate.opsForValue().set(realKey, result, ann.l2TimeOut(), TimeUnit.SECONDS);
            cache.put(realKey, result);
        }
        return result;
    }
}

Apply the custom annotation to service methods, eliminating manual cache code:

@DoubleCache(cacheName = "order", key = "#id", type = CacheType.FULL)
public Order getOrderById(Long id) {
    return orderMapper.selectOne(new LambdaQueryWrapper<Order>().eq(Order::getId, id));
}

@DoubleCache(cacheName = "order", key = "#order.id", type = CacheType.PUT)
public Order updateOrder(Order order) {
    orderMapper.updateById(order);
    return order;
}

@DoubleCache(cacheName = "order", key = "#id", type = CacheType.DELETE)
public void deleteOrder(Long id) {
    orderMapper.deleteById(id);
}

Summary

The article demonstrates three progressively less intrusive ways to manage a two‑level cache in a Spring Boot application: a fully manual approach, Spring’s built‑in cache annotations, and a custom @DoubleCache annotation powered by an AOP aspect. Choosing the right method depends on project complexity, consistency requirements, and the desired balance between control and code cleanliness.