How to Integrate Redis with Spring Boot: A Step-by-Step Guide.

Redis: Redis is an open-source, in-memory data structure store used as a database, cache, and message broker.

Redis is an open-source, in-memory data structure used as a database, cache, and message broker for applications requiring high performance.

In this article, we are going to explore: Redis being used as a cache with Spring Boot.

Prerequisites:

• Java 17+
• Sprint Boot 3.5+
• Maven
• Redis Server installed locally

Step 1: Add Redis as a Dependency

Add the Spring Boot Redis starter dependency to your pom.xml

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-redis</artifactId>
xml    <version>3.5.7</version>
</dependency>

Step 2: Configure Redis Properties

Add Redis Configuration to your “application.properties”, specifying the host name and the port number.

# Redis specific configuration
spring.data.redis.port=6379
spring.data.redis.host=localhost

Step 3: Create a Redis Configuration Class

Create a configuration class to setup the RedisTemplate bean in your “config” package. This will be used to communicate with the Redis server

@Configuration
public class RedisConfig {
    @Bean
    RedisTemplate<String, Object> getRedisTemplate(RedisConnectionFactory redisConnectionFactory) {
        RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();
        redisTemplate.setConnectionFactory(redisConnectionFactory);
        return redisTemplate;
    }
}

Step 4: Implement Caching in your Service

Inject and use RedisTemplate in your service class to implement caching logic. I will be using my application as an example. The ProductService makes calls to 3rd party service called “FakeStore” which is a fake implementation for E-commerce products.

@Service
public class ProductService {

    @Autowired
    private RedisTemplate<String, Object> redisTemplate;

    public Product getProductById(Long id) {
        // Check cache first
        FakeStoreProductDto cachedProduct = (FakeStoreProductDto) 
            redisTemplate.opsForHash().get("PRODUCTS", id);

        if (cachedProduct == null) {
            // Cache miss - fetch from external API
            FakeStoreProductDto product = apiClient.getProductById(id);

            if (product != null) {
                // Store in cache for future requests
                redisTemplate.opsForHash().put("PRODUCTS", id, product);
                return convertToProduct(product);
            }
            return null;
        }

        // Cache hit - return cached data
        return convertToProduct(cachedProduct);
    }
}

Step 5: Implement Serializable Interface

The object intended to be stored should implement Serializable interface as this allows Serialization of the object while storing in the Redis Cache.

public class FakeStoreProductDto implements Serializable {
    private Long id;
    private String title;
    private Double price;
    private String description;
    private String category;
    private String image;
}

In our case, we are storing FakeStoreProductDto in our cache, hence implementing Serializable interface.

Step 6: Start Redis Server:

Ensure your Redis Server is running on your local machine:

redis-server

Key Benefits:

• Performance: Reduces API calls to external services
• Cost: Reduces cost for the 3rd party external services by caching content.
• Reliability: Provides fallback when external services are slow.

Github Repo

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