Spring Boot + MapStruct: Real-World Examples Explained

🧾 Introduction

In any real-world Java backend application, you deal with two very different types of objects:

• Entities: Objects mapped to your database tables (using JPA)
• DTOs (Data Transfer Objects): Objects used to communicate between layers or over APIs

If you’ve ever manually copied fields between these types, you know how repetitive and error-prone it can get. That’s where MapStruct comes in.

MapStruct is a compile-time code generator that automates the mapping between these objects — without reflection, and with excellent performance. It makes your code cleaner, more maintainable, and less error-prone.

In this article, we’ll explore:

• What MapStruct is
• How to integrate it in a Spring Boot project
• Mapping entities to DTOs (and vice versa)
• Handling enums, dates, nested objects, and pagination
• Writing custom mappings
• How MapStruct improves testing and design

Let’s dive in.

What is MapStruct?

MapStruct is a Java annotation processor that generates type-safe and performance-optimized mappers at compile time.

Unlike libraries like ModelMapper or Dozer, MapStruct doesn’t use reflection — making it extremely fast and…