How to Fix Caching in Spring Boot with Caffeine to Control Cache Based on Output

Discover how to resolve the error in `Spring Boot` caching using `Caffeine`, ensuring the cache works correctly based on your object properties.
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Fixing Caching Issues in Spring Boot with Caffeine

Caching is a powerful feature that can greatly increase the performance of your Spring Boot applications. However, misconfigurations can lead to frustrating errors. In this guide, we'll explore a specific problem regarding cache control using Caffeine and how to solve it effectively.

The Problem: Caching with Conditions

In a recent scenario, a developer encountered an error while trying to use the @ CachePut annotation to store responses conditionally based on the properties of the cache output. The original code looked like this:

[[See Video to Reveal this Text or Code Snippet]]

However, running this code resulted in the following error:

[[See Video to Reveal this Text or Code Snippet]]

This error indicates that the expression language (SpEL) used in the unless attribute could not access the properties desc and title of the resulting DogInHouseResponse object as expected.

Analyzing the Error Message

The core issue, as indicated by the error message, is that the fields desc and title may not be public, or the expressions used to reference them are incorrect. In Java, if a property is private, it requires a getter method to be accessed using SpEL.

The Solution: Use Getter Methods

To resolve this issue, you need to ensure that the properties inside your DogInHouseResponse class are accessible. Here's how to do that:

Check Your Class Definition

First, verify your DogInHouseResponse class structure:

[[See Video to Reveal this Text or Code Snippet]]

Update Your Caching Logic

Then, modify your caching logic to use the getter methods instead of trying to access the properties directly:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

Using caching in Spring Boot with Caffeine can dramatically enhance your application's performance. However, it is crucial to access object properties correctly when defining caching conditions. By using getter methods where necessary, you can eliminate the SpelEvaluationException and manage your cache effectively.

Don't let caching errors hold back your development progress. With these adjustments, you can confidently use caching in your Spring Boot applications.

If you have further questions about using caching in applications, feel free to leave a comment below!