How to Autopopulate Your Database with Spring Boot on Initialization

Learn how to effectively `autopopulate your Spring Boot database` only on initialization, using conditions to load JSON resources.
---

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Autopopulate Database with Spring Boot

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Autopopulate Your Database with Spring Boot on Initialization

When developing a Spring Boot application, especially one that relies on pre-populated tables, the ability to efficiently load your data at startup can save you a lot of time and eliminate unnecessary manual loading. In this guide, we’ll explore how to autopopulate your database using JSON files upon initialization of your application.

The Initial Problem

Imagine you have a Spring Boot application with numerous tables that need to be preloaded with data from JSON files. You might be using a code snippet similar to the one outlined below, designed to load these tables whenever your application runs.

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

However, in your attempt to optimize this process, you’re looking for a way to ensure that data is only loaded during the database initialization phase. Furthermore, you’ve encountered a challenge where your EntityManager seems to be null.

This can occur when the class you’re using isn't recognized as “Spring managed,” thus making dependency injection ineffective.

A Step toward a Solution

Step-by-Step Implementation

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

Modify Your PreLoader Class: Update the PreLoader class to include the @ ConditionalOnProperty annotation. This will ensure that the preloading logic is executed only when you want it to – triggered by the value of initialize.

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

Load Your Resource Files: Ensure that you properly load your JSON resource files, as shown below.

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

Conclusion

By following these steps, you can effectively control the data preloading in your Spring Boot application. Using the @ ConditionalOnProperty annotation provides a simple, clear, and effective way to manage the initialization of your database, allowing you to leverage JSON files efficiently while resolving the issue of uninitialized dependency injections.

This approach not only streamlines your application’s setup but also boosts maintainability and clarity.

Feel free to implement these changes in your own projects, and remember, happy coding!