Скачать или смотреть Can You Share a Transaction Between EntityManager and a Repository in Spring Boot?

Discover how to successfully use EntityManager and repositories together in a single @ Transactional method using TestEntityManager in Spring Boot.
---
This video is based on the question https://stackoverflow.com/q/71200076/ asked by the user 'user3429660' ( https://stackoverflow.com/u/3429660/ ) and on the answer https://stackoverflow.com/a/71212574/ provided by the user 'Semyon Kirekov' ( https://stackoverflow.com/u/9167731/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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: Can share a transaction between EntittManager and a Repository

Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/l...
The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/... ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
Can You Share a Transaction Between EntityManager and a Repository in Spring Boot?

Spring Boot is a robust framework that leverages Hibernate for seamless data management. However, developers sometimes face challenges when trying to manage transactions across various components, such as EntityManager and repository classes in a single @ Transactional method. This guide dives into the problem and provides a clear solution to ensure that your transactions are shared effectively across both EntityManager and repositories.

The Problem

Imagine you have a scenario where you are using a repository to save multiple entities and an EntityManager to fetch them within the same transaction. You might expect both to work seamlessly together; however, you might run into a situation where the data saved through the repository is not immediately visible to the EntityManager. This usually occurs when you flush the changes to the repository but fail to connect the EntityManager with the current transaction context.

Example Scenario

Here is a snippet of code demonstrating this issue:

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

As shown in the test, even though three JobCategory entities are successfully saved and the repository reflects the correct count, querying through the EntityManager yields unexpected results, due to the separation of the transaction contexts.

The Solution: Utilizing TestEntityManager

To effectively manage transactions across both a repository and an EntityManager, you can use Spring's TestEntityManager. This wrapper around EntityManager ensures that it is always bonded to the current Spring transaction, thus enabling you to access changes made by the repository.

Step-by-Step Guide

Inject TestEntityManager: In your test class, replace the existing EntityManager creation with the TestEntityManager.

Modify Your Code:
Update your codebase to make use of the TestEntityManager as shown below:

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

Key Changes Explained

Injecting TestEntityManager: By doing this, you ensure the EntityManager used in your tests will participate in the same transaction as your repository's operations.

Calling getEntityManager(): Using the getEntityManager() method from TestEntityManager gives you a connection to the exact transaction context, allowing you to accurately query the saved entities without running into issues.

Conclusion

Using EntityManager and repository patterns together in Spring Boot tests can sometimes be tricky, but with TestEntityManager, this can be streamlined effectively. By ensuring that the EntityManager and repository share the same transactional context, you can rest assured that your persistence operations will yield consistent and accurate results.

Next time you find yourself in a similar scenario, keep this solution in mind to enhance your Spring Boot application's data management capabilities!