MapStruct vs. ModelMapper in Spring Boot: The Ultimate Guide to Optimized Entity-DTO Mapping

Data transfer in modern Spring Boot applications revolves heavily around converting Entity objects (database models) into DTOs (Data Transfer Objects) and vice versa. With increasing project complexity, manually handling these conversions can result in repetitive, error-prone code. This is where automated mapping libraries like MapStruct and ModelMapper come into play.

In this article, we will dive deep into the use cases, advantages, performance comparisons, and best practices of using both MapStruct and ModelMapper. By the end, you’ll have a clear understanding of which library to use for your project, along with a modernized, practical example.

Why Entity-DTO Conversion?

Before we get into the technical comparison, let’s clarify the roles of Entity and DTO in modern applications.

Entity:

• Represents the database model.
• Contains all fields mapped to the database, including sensitive data like passwords or internal fields.
• Problem: Sending an Entity directly to the client can expose unnecessary and potentially sensitive information.

DTO:

• A simplified version of…