Using Spring Boot with H2 Database and Redis for Caching

November 07, 2025

#1

This guide shows how to combine H2 as a database and Redis as a cache in Spring Boot for faster performance.

1. Add Dependencies

<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
  <groupId>com.h2database</groupId>
  <artifactId>h2</artifactId>
</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>

2. Configure H2 and Redis

spring.datasource.url=jdbc:h2:mem:cachedb
spring.datasource.driver-class-name=org.h2.Driver
spring.jpa.hibernate.ddl-auto=create

spring.redis.host=localhost
spring.redis.port=6379
spring.cache.type=redis

3. Enable Caching

@SpringBootApplication
@EnableCaching
public class DemoApplication {
  public static void main(String[] args) {
    SpringApplication.run(DemoApplication.class, args);
  }
}

4. Create Entity

@Entity
public class Product {
  @Id @GeneratedValue
  private Long id;
  private String name;
  private double price;
}

5. Repository

public interface ProductRepository extends JpaRepository<Product, Long> {}

6. Service with Cache

@Service
public class ProductService {
  private final ProductRepository repo;

  public ProductService(ProductRepository repo) {
    this.repo = repo;
  }

  @Cacheable("products")
  public Product findById(Long id) {
    return repo.findById(id).orElse(null);
  }

  @CacheEvict(value = "products", allEntries = true)
  public Product save(Product product) {
    return repo.save(product);
  }
}

7. Test the Cache

1. Call findById(1) → hits H2 database.
2. Call again → returns instantly from Redis cache.
3. Save new data → cache is cleared automatically.