How to Use Caching in Spring Boot: Simple Guide with Examples

To use caching in Spring Boot, add @EnableCaching to your main class and annotate methods with @Cacheable to store results. Spring Boot manages cache storage automatically, improving performance by avoiding repeated method calls.

Syntax

Enable caching by adding @EnableCaching on a configuration or main class. Use @Cacheable on methods whose results you want to cache. Optionally, use @CachePut to update cache and @CacheEvict to remove entries.

• @EnableCaching: Activates Spring's cache support.
• @Cacheable("cacheName"): Caches method return values.
• @CachePut("cacheName"): Updates cache without skipping method execution.
• @CacheEvict("cacheName"): Removes cache entries.

java

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.cache.annotation.CachePut;
import org.springframework.cache.annotation.CacheEvict;
import org.springframework.stereotype.Service;

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

@Service
public class DataService {

    @Cacheable("items")
    public String getItem(String id) {
        // Simulate slow method
        try { Thread.sleep(2000); } catch (InterruptedException e) {}
        return "Item-" + id;
    }

    @CachePut(value = "items", key = "#id")
    public String updateItem(String id, String newValue) {
        return newValue;
    }

    @CacheEvict(value = "items", key = "#id")
    public void removeItem(String id) {
        // Removes item from cache
    }
}

Example

This example shows a Spring Boot app with caching enabled. The getItem method caches its result, so the first call takes 2 seconds but subsequent calls return instantly from cache.

java

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.cache.annotation.EnableCaching;
import org.springframework.cache.annotation.Cacheable;
import org.springframework.stereotype.Service;

@SpringBootApplication
@EnableCaching
public class CacheDemoApplication {
    public static void main(String[] args) {
        var context = SpringApplication.run(CacheDemoApplication.class, args);
        var service = context.getBean(DataService.class);

        long start = System.currentTimeMillis();
        System.out.println(service.getItem("123")); // Takes ~2 seconds
        System.out.println("First call took: " + (System.currentTimeMillis() - start) + " ms");

        start = System.currentTimeMillis();
        System.out.println(service.getItem("123")); // Instant from cache
        System.out.println("Second call took: " + (System.currentTimeMillis() - start) + " ms");
    }
}

@Service
class DataService {
    @Cacheable("items")
    public String getItem(String id) {
        try { Thread.sleep(2000); } catch (InterruptedException e) {}
        return "Item-" + id;
    }
}

Output

Item-123
First call took: 2003 ms
Item-123
Second call took: 1 ms

Common Pitfalls

• Forgetting @EnableCaching disables caching.
• Using @Cacheable on private or final methods won't work because Spring proxies can't intercept them.
• Cache keys default to method parameters; complex objects may need custom key generators.
• Not configuring a cache manager defaults to simple in-memory cache, which may not suit production.

java

/* Wrong: Missing @EnableCaching - caching won't work */
@SpringBootApplication
public class App {}

/* Right: Add @EnableCaching to enable caching */
@SpringBootApplication
@EnableCaching
public class App {}

Quick Reference

Annotation	Purpose
@EnableCaching	Enable Spring caching support
@Cacheable	Cache method return values
@CachePut	Update cache without skipping method execution
@CacheEvict	Remove entries from cache

Key Takeaways

Add @EnableCaching to your Spring Boot application to activate caching.

Use @Cacheable on methods to cache their results and improve performance.

Remember that caching works only on public methods due to Spring proxies.

Configure a proper cache manager for production use beyond default in-memory cache.

Use @CachePut and @CacheEvict to update or clear cache entries as needed.