pagination-dto-mapping-sample

Extends pagination-pageable-sample with DTO mapping.

What It Demonstrates

The repository returns domain objects — Customer.

The application layer converts the result into view objects — CustomerView — without rebuilding pagination metadata.

The key idea: PageResult.map() transforms the content across layers while preserving page number, size and total count unchanged.

Structure

All code is in a single file: PaginationDtoMapping.java

PaginationDtoMapping.java
│
├── Customer                # Domain model — record with id and name
├── CustomerView            # DTO — read model for the application layer
├── CustomerMapper          # Maps Customer → CustomerView
├── PageRequest             # Pagination request — page number and size
├── PageResult<T>           # Pagination result — content + metadata + map()
├── CustomerRepository      # Data access — returns PageResult<Customer>
├── FakeCustomerTable       # In-memory data source — simulates a database table
└── PaginationDtoMapping    # Entry point + demo()

Key Points

PageResult.map() preserves metadata. Converts the content type without touching page number, size or total — no manual reconstruction needed.

Each layer owns its transformation. The repository returns PageResult<Customer>. The application layer maps it to PageResult<CustomerView> in a single call.

CustomerMapper holds the mapping logic. Domain objects and view objects stay clean with no cross-layer constructors.

Console Output

PageResult[content=[CustomerView[id=1, name=Alice], CustomerView[id=2, name=Bob]], page=0, size=2, total=5]

The repository returned Customer records. The application layer received CustomerView records. Pagination metadata passed through unchanged.

Run

./mvnw spring-boot:run

See also

• Previous: pagination-pageable-sample
• Next: pagination-sorting-sample