Skeleton for Spring Boot based REST services (proof of concept)

Spring Boot based microservice PoC with a sample Person API and its implementation

Features

• REST APIs for data maintenance
• Built-in Swagger UI
• HATEOAS support
• Complex freeform query support using HTTP GET
• Validation
• Optimistic locking
• default implementation for maintenance functions so no code required for those

Parts

bom

Dependency and plugin management for the whole project. You should not use any dependencies/plugins which are not declared and configured here.

root-api

The API root which you can extend. The main API is the generic MaintenanceAPI which has a default implementation of returning HTTP 501 - Not implemented.

core

The core framework functions:

• exception handling ExceptionHandlerControllerAdvice
• a (n abstract) default implementation for MaintenanceAPI - AbstractMaintenanceController
• a generic data storage service for the controller - MaintenanceService
• a generic JPA implementation for the MaintenanceService - AbstractJpaMaintenanceService
• a root entity model - BaseEntity
• a JPA repository root - BaseJpaRepository
• a generic MapStruct mapper for mapping between the API DTOs and the stored entities - EntityMapper
• resources/changelog-master.xml - LiquiBase setup for maintaining database lifecycle

and of course several other classes to support the above

person-api

A sample API to store simple data about people:

• the maintenance API for the Person object - PersonAPI
• the data model of a person - PersonDTO

person

A sample implementation of the Person API:

• the entity -Person
• the JPA repository - PersonRepository
• model mapper - PersonMapper
• service for data management - PersonService
• database model for a person - resources/modulechangelog/*.xml
• a sample Spring Boot app to demonstrate the operation - PersonApplication

Components used

• Lombok
• MapStruct
• Spring Boot 3.0.6
• Spring Cloud 2022.0.2
• SpringDoc OpenAPI 3 (Swagger) annotations with Swagger UI

Preconditions

Requires a PostgreSQL database connection to work. You can set up your in person/src/main/resources/application.yml. Or alternatively you can run one with the preconfigured connection parameters in Docker:

docker run -it -p 5432:5432 -e POSTGRES_DB=dev -e POSTGRES_USER=dev -e POSTGRES_PASSWORD=dev postgres:alpine 

Running the sample

1. run mvn clean package for the bom
2. cd person
3. run mvn spring-boot:run
4. navigate your browser to http://localhost:8080/swagger-ui.html

ToDo

• Add unit tests
• Add OAuth2
• Implement other storage models
  • ElasticSearch
  • MongoDB
• Implement non-string search criteria
• Record auditing
• Add Kafka queueing
• Move to the cloud: Spring Cloud Kubernetes