@CachePut for updating cache in Spring Boot - Mini Project: Build & Apply

Using @CachePut to Update Cache in Spring Boot

📖 Scenario: You are building a simple Spring Boot service that manages product prices. You want to cache product prices to improve performance. When a product price is updated, you want to update the cache immediately to keep it fresh.

🎯 Goal: Build a Spring Boot service with a method that updates a product price and uses @CachePut to update the cache with the new price.

📋 What You'll Learn

Create a Map<String, Double> called productPrices with initial product prices

Create a String variable called cacheName with value "prices"

Create a method updatePrice that takes String product and Double price and updates productPrices

Annotate updatePrice with @CachePut to update the cache named prices

💡 Why This Matters

🌍 Real World

Caching updated data in services is common to improve performance and keep data fresh in web applications.

💼 Career

Understanding @CachePut is important for backend developers working with Spring Boot to manage cache updates efficiently.

1

Create initial product prices map

Create a Map<String, Double> called productPrices with these exact entries: "apple" with 1.0, "banana" with 0.5, and "orange" with 0.8.

Spring Boot

import java.util.Map;
import java.util.HashMap;

public class PriceService {
    // Your code here
}

Need a hint?

Use new HashMap<>() and add entries with put.

2

Add cache name variable

Add a String variable called cacheName and set it to the exact value "prices".

Spring Boot

import java.util.Map;
import java.util.HashMap;

public class PriceService {
    Map productPrices = new HashMap() {{
        put("apple", 1.0);
        put("banana", 0.5);
        put("orange", 0.8);
    }};
    // Your code here
}

Need a hint?

Declare a String variable and assign the value "prices".

3

Create updatePrice method with cache update

Create a public method updatePrice that takes String product and Double price. Inside, update productPrices by putting the new price for the product. Annotate this method with @CachePut(cacheNames = "prices", key = "#product") to update the cache entry for the product.

Spring Boot

import java.util.Map;
import java.util.HashMap;
import org.springframework.cache.annotation.CachePut;

public class PriceService {
    Map productPrices = new HashMap() {{
        put("apple", 1.0);
        put("banana", 0.5);
        put("orange", 0.8);
    }};
    String cacheName = "prices";

    // Your code here
}

Need a hint?

Use @CachePut with cacheNames = "prices" and key = "#product". Return the updated price.

4

Add class-level annotation and complete service

Add the @Service annotation to the PriceService class to make it a Spring service component.

Spring Boot

import java.util.Map;
import java.util.HashMap;
import org.springframework.cache.annotation.CachePut;
import org.springframework.stereotype.Service;

// Your code here
public class PriceService {
    Map productPrices = new HashMap() {{
        put("apple", 1.0);
        put("banana", 0.5);
        put("orange", 0.8);
    }};
    String cacheName = "prices";

    @CachePut(cacheNames = "prices", key = "#product")
    public Double updatePrice(String product, Double price) {
        productPrices.put(product, price);
        return price;
    }
}

Need a hint?

Import and add @Service annotation above the class declaration.