# mrpyaesone/spring-rest-crud-helloworld architecture

> Architecture diagram of the GitHub repository mrpyaesone/spring-rest-crud-helloworld, generated by GitDiagram from its file tree, README and a sample of source files (last updated 2026-08-02). It is an AI-made overview: check details against the source.

- Interactive diagram: https://gitdiagram.com/mrpyaesone/spring-rest-crud-helloworld
- Repository: https://github.com/mrpyaesone/spring-rest-crud-helloworld

## Overview

#### Purpose and Entry Point
A compact Spring Boot REST CRUD service for `Person` records backed by MySQL. The executable application entry point is `src/main/java/com/ps/rest/crud/helloworld/SpringRestCrudHelloworldApplication.java`; Maven build/dependency management is defined in `pom.xml`.

#### HTTP API Layer
`src/main/java/com/ps/rest/crud/helloworld/controller/PersonCrudController.java` exposes the REST-facing person CRUD operations. It is the boundary between HTTP request/response handling and the application’s service/data-access layers.

#### Domain Model
`src/main/java/com/ps/rest/crud/helloworld/model/Person.java` defines the person data shape exchanged through the controller and persisted in MySQL. This model is the shared contract across API, service, and database code.

#### Service and Persistence Abstraction
`src/main/java/com/ps/rest/crud/helloworld/service/PersonCRUDRepo.java` defines the person persistence/service contract, while `src/main/java/com/ps/rest/crud/helloworld/service/PersonCRUDImplementation.java` supplies its implementation. The controller should depend on this abstraction rather than directly on SQL-specific code.

#### MySQL Data Access
`src/main/java/com/ps/rest/crud/helloworld/db/CRUD.java` defines generic CRUD-oriented database behavior. `src/main/java/com/ps/rest/crud/helloworld/db/MySQLImpl.java` is the concrete MySQL integration, with database-related constants centralized in `src/main/java/com/ps/rest/crud/helloworld/db/DBConstants.java`. This is the material boundary between Java application logic and SQL/database connectivity.

#### Primary Flow
Requests flow: client → `PersonCrudController` → `PersonCRUDRepo` / `PersonCRUDImplementation` → `CRUD` / `MySQLImpl` → MySQL. Results return through the same layers as `Person` objects or API responses. SQL schema/seed setup is supplied separately at `sql-data/crud_rest_helloworld.sql`.

#### Runtime, Configuration, and Infrastructure
The runtime is Spring Boot on the JVM, packaged and built with Maven. Application/database settings are located in `src/main/resources/application.properties` and `src/main/resources/application.yml`. MySQL-oriented container infrastructure is provided by `docker/spring-mysql-docker-compose.yml`; `docker/Dockerfile` packages the application container. CI execution is configured in `.circleci/config.yml`.

Main entry points: [`src/main/java/com/ps/rest/crud/helloworld/SpringRestCrudHelloworldApplication.java`](https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/src/main/java/com/ps/rest/crud/helloworld/SpringRestCrudHelloworldApplication.java) (Spring Boot entry point), [`src/main/java/com/ps/rest/crud/helloworld/service/PersonCRUDImplementation.java`](https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/src/main/java/com/ps/rest/crud/helloworld/service/PersonCRUDImplementation.java) (Person CRUD implementation), [`src/main/java/com/ps/rest/crud/helloworld/controller/PersonCrudController.java`](https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/src/main/java/com/ps/rest/crud/helloworld/controller/PersonCrudController.java) (Person CRUD controller), [`src/main/java/com/ps/rest/crud/helloworld/db/MySQLImpl.java`](https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/src/main/java/com/ps/rest/crud/helloworld/db/MySQLImpl.java) (MySQL implementation)

## Diagram (Mermaid)

```mermaid
flowchart TD

subgraph group_application["Spring application"]
  node_app{{"Spring Boot entry point<br/>application bootstrap"}}
  node_controller["Person CRUD controller<br/>REST controller"]
  node_person["Person<br/>domain model<br/>[Person.java]"]
  node_person_repo["Person CRUD contract<br/>service interface"]
  node_person_service["Person CRUD implementation<br/>service implementation"]
end

subgraph group_persistence["Persistence"]
  node_crud["Generic CRUD contract<br/>database interface<br/>[CRUD.java]"]
  node_mysql_impl["MySQL implementation<br/>database adapter<br/>[MySQLImpl.java]"]
  node_db_constants["Database constants<br/>database settings<br/>[DBConstants.java]"]
  node_mysql[("MySQL<br/>database")]
  node_schema["Schema and seed SQL<br/>SQL setup"]
end

subgraph group_delivery["Build and deployment"]
  node_properties["Application properties<br/>runtime configuration"]
  node_yaml["Application YAML<br/>runtime configuration<br/>[application.yml]"]
  node_maven["Maven build<br/>build definition<br/>[pom.xml]"]
  node_dockerfile["Application container<br/>container build"]
  node_compose["MySQL Compose stack<br/>container infrastructure"]
  node_ci["CircleCI pipeline<br/>CI configuration<br/>[config.yml]"]
end

node_client(("API client<br/>external client"))

node_client -->|"HTTP CRUD requests"| node_controller
node_app -->|"boots API"| node_controller
node_controller -->|"uses contract"| node_person_repo
node_controller -->|"maps requests and responses"| node_person
node_person_service -->|"implements"| node_person_repo
node_person_repo -.->|"delegates to"| node_person_service
node_person_service -->|"uses CRUD abstraction"| node_crud
node_person_service -->|"persists"| node_person
node_mysql_impl -->|"implements"| node_crud
node_crud -.->|"backed by"| node_mysql_impl
node_mysql_impl -->|"SQL connectivity"| node_mysql
node_db_constants -.->|"connection constants"| node_mysql_impl
node_schema -->|"initializes"| node_mysql
node_properties -.->|"configures runtime"| node_app
node_yaml -.->|"configures runtime"| node_app
node_maven -->|"builds and packages"| node_app
node_dockerfile -->|"packages"| node_app
node_compose -->|"runs database"| node_mysql
node_ci -->|"runs build"| node_maven

click node_app "https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/src/main/java/com/ps/rest/crud/helloworld/SpringRestCrudHelloworldApplication.java"
click node_controller "https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/src/main/java/com/ps/rest/crud/helloworld/controller/PersonCrudController.java"
click node_person "https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/src/main/java/com/ps/rest/crud/helloworld/model/Person.java"
click node_person_repo "https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/src/main/java/com/ps/rest/crud/helloworld/service/PersonCRUDRepo.java"
click node_person_service "https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/src/main/java/com/ps/rest/crud/helloworld/service/PersonCRUDImplementation.java"
click node_crud "https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/src/main/java/com/ps/rest/crud/helloworld/db/CRUD.java"
click node_mysql_impl "https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/src/main/java/com/ps/rest/crud/helloworld/db/MySQLImpl.java"
click node_db_constants "https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/src/main/java/com/ps/rest/crud/helloworld/db/DBConstants.java"
click node_schema "https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/sql-data/crud_rest_helloworld.sql"
click node_properties "https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/src/main/resources/application.properties"
click node_yaml "https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/src/main/resources/application.yml"
click node_maven "https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/pom.xml"
click node_dockerfile "https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/docker/Dockerfile"
click node_compose "https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/docker/spring-mysql-docker-compose.yml"
click node_ci "https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/.circleci/config.yml"

classDef toneNeutral fill:#f8fafc,stroke:#334155,stroke-width:1.5px,color:#0f172a
classDef toneBlue fill:#dbeafe,stroke:#2563eb,stroke-width:1.5px,color:#172554
classDef toneAmber fill:#fef3c7,stroke:#d97706,stroke-width:1.5px,color:#78350f
classDef toneMint fill:#dcfce7,stroke:#16a34a,stroke-width:1.5px,color:#14532d
classDef toneRose fill:#ffe4e6,stroke:#e11d48,stroke-width:1.5px,color:#881337
classDef toneIndigo fill:#e0e7ff,stroke:#4f46e5,stroke-width:1.5px,color:#312e81
classDef toneTeal fill:#ccfbf1,stroke:#0f766e,stroke-width:1.5px,color:#134e4a
class node_app,node_controller,node_person,node_person_repo,node_person_service toneBlue
class node_crud,node_mysql_impl,node_db_constants,node_mysql,node_schema toneAmber
class node_properties,node_yaml,node_maven,node_dockerfile,node_compose,node_ci toneMint
class node_client toneNeutral
```

## Components

### Spring application

- [Spring Boot entry point](https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/src/main/java/com/ps/rest/crud/helloworld/SpringRestCrudHelloworldApplication.java): application bootstrap · `src/main/java/com/ps/rest/crud/helloworld/SpringRestCrudHelloworldApplication.java`
- [Person CRUD controller](https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/src/main/java/com/ps/rest/crud/helloworld/controller/PersonCrudController.java): REST controller · `src/main/java/com/ps/rest/crud/helloworld/controller/PersonCrudController.java`
- [Person](https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/src/main/java/com/ps/rest/crud/helloworld/model/Person.java): domain model · Shared API and persistence record shape. · `src/main/java/com/ps/rest/crud/helloworld/model/Person.java`
- [Person CRUD contract](https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/src/main/java/com/ps/rest/crud/helloworld/service/PersonCRUDRepo.java): service interface · `src/main/java/com/ps/rest/crud/helloworld/service/PersonCRUDRepo.java`
- [Person CRUD implementation](https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/src/main/java/com/ps/rest/crud/helloworld/service/PersonCRUDImplementation.java): service implementation · `src/main/java/com/ps/rest/crud/helloworld/service/PersonCRUDImplementation.java`

### Persistence

- [Generic CRUD contract](https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/src/main/java/com/ps/rest/crud/helloworld/db/CRUD.java): database interface · `src/main/java/com/ps/rest/crud/helloworld/db/CRUD.java`
- [MySQL implementation](https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/src/main/java/com/ps/rest/crud/helloworld/db/MySQLImpl.java): database adapter · Concrete Java-to-MySQL integration. · `src/main/java/com/ps/rest/crud/helloworld/db/MySQLImpl.java`
- [Database constants](https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/src/main/java/com/ps/rest/crud/helloworld/db/DBConstants.java): database settings · `src/main/java/com/ps/rest/crud/helloworld/db/DBConstants.java`
- **MySQL**: database
- [Schema and seed SQL](https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/sql-data/crud_rest_helloworld.sql): SQL setup · `sql-data/crud_rest_helloworld.sql`

### Build and deployment

- [Application properties](https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/src/main/resources/application.properties): runtime configuration · `src/main/resources/application.properties`
- [Application YAML](https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/src/main/resources/application.yml): runtime configuration · `src/main/resources/application.yml`
- [Maven build](https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/pom.xml): build definition · `pom.xml`
- [Application container](https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/docker/Dockerfile): container build · `docker/Dockerfile`
- [MySQL Compose stack](https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/docker/spring-mysql-docker-compose.yml): container infrastructure · `docker/spring-mysql-docker-compose.yml`
- [CircleCI pipeline](https://github.com/mrpyaesone/spring-rest-crud-helloworld/blob/master/.circleci/config.yml): CI configuration · `.circleci/config.yml`

### Other components

- **API client**: external client

## Connections

- API client → Person CRUD controller: HTTP CRUD requests
- Spring Boot entry point → Person CRUD controller: boots API
- Person CRUD controller → Person CRUD contract: uses contract
- Person CRUD controller → Person: maps requests and responses
- Person CRUD implementation → Person CRUD contract: implements
- Person CRUD contract → Person CRUD implementation: delegates to
- Person CRUD implementation → Generic CRUD contract: uses CRUD abstraction
- Person CRUD implementation → Person: persists
- MySQL implementation → Generic CRUD contract: implements
- Generic CRUD contract → MySQL implementation: backed by
- MySQL implementation → MySQL: SQL connectivity
- Database constants → MySQL implementation: connection constants
- Schema and seed SQL → MySQL: initializes
- Application properties → Spring Boot entry point: configures runtime
- Application YAML → Spring Boot entry point: configures runtime
- Maven build → Spring Boot entry point: builds and packages
- Application container → Spring Boot entry point: packages
- MySQL Compose stack → MySQL: runs database
- CircleCI pipeline → Maven build: runs build