Скачать или смотреть Resolving ModelMapper Configuration Conflicts in Spring Boot Applications

Discover how to solve the issue of conflicting `ModelMapper` configurations in your Spring Boot application, allowing for tailored object mappings in different service classes.
---
This video is based on the question https://stackoverflow.com/q/65330163/ asked by the user 'Aldo Inácio da Silva' ( https://stackoverflow.com/u/8405699/ ) and on the answer https://stackoverflow.com/a/65346728/ provided by the user 'Aldo Inácio da Silva' ( https://stackoverflow.com/u/8405699/ ) 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: ModelMapper - A mapping already exists - Two configurations

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.
---
Resolving ModelMapper Configuration Conflicts in Spring Boot Applications

When developing Spring Boot applications, managing object mapping between entities and Data Transfer Objects (DTOs) can sometimes lead to frustrating issues, especially when using libraries like ModelMapper. One common problem that developers encounter is a conflict arising from multiple configurations intended for similar mappings. In this post, we will explore a specific scenario involving ModelMapper and its configurations, and how you can resolve it effectively.

The Problem: Mapping Conflicts

In our example, we have two service classes that utilize ModelMapper to transform entity objects into DTOs. Each class was designed to handle mappings differently, but they ran into a mapping conflict during execution:

p strong A mapping already exists for com.closeupinternational.authorization.dtos.CompanyServiceModuleDTO.setCompanyService(). /strong /p

This error occurs because ModelMapper treats the mappings as global and shared across all instances unless specified otherwise. This leads to confusion and conflict when two classes try to register similar mappings.

Why It Happens

The root cause of this problem is that ModelMapper is typically treated as a singleton when instantiated by Spring's Dependency Injection. When multiple classes attempt to register their own mappings on the shared instance, they step on each other’s feet, resulting in the aforementioned error.

The Solution: Separate Instances of ModelMapper

To tackle this issue, a straightforward solution is to instantiate ModelMapper separately within each service class, rather than relying on the singleton instance provided by Spring. Here’s how you can implement this fix.

Step-by-Step Implementation

Create Separate Instances: Modify your service classes to instantiate ModelMapper within their constructors. This ensures that each class has its own unique ModelMapper instance.

Update the Service Implementation: Here's how you can implement it:

Refactoring CompanyProfileImpl

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

Resulting Benefits

Isolation: Each service class maintains its own mapping configurations without affecting others. This avoids the possibility of contention and conflicting mappings.

Flexibility: You can now tailor your mappings according to the specific needs of each service, opting to include or exclude relationships as necessary.

Conclusion

In summary, conflicts in ModelMapper configurations can hinder the development of sophisticated Spring Boot applications. By ensuring that each service class has its own instance of ModelMapper, you can avoid these conflicts and optimize your object mapping strategies.

Always remember to check your mapping configurations and understand how shared instances can lead to unexpected behavior. By following the outlined steps, you can enhance the robustness of your application and streamline the development process.

Feel free to share your experiences or further questions regarding ModelMapper configurations in the comments below!