About the project

This is a demo project for study purposes. It consists of a simple fullstack CRUD project comprising a Java web service as backend plus a Bootstrap frontend built with Spring Boot, Apache TomCat and PostgresSQL as database.

About the architecture

• Backend: the web service
  • Java with Spring Boot framework (version: 3.2.10-SNAPSHOT);
    • Java version: 17.
• Frontend:
  • Bootstrap (version: 5.3.3) with CDN;
  • Jquery (version: 3.7.1) with CDN.
• Database:
  • Postgres 17 (the version will be always the last thanks to "latest" tag defined in the docker-compose.yaml file).
• Pattern used: a simplified Layered Architecture (see the logical layers below)
  • The REST Controller class is the UserResource.java file, which is our Resource Layer, being responsible to control the resources pertaining to the Postgres Table tb_users, i.e. receiving the requests from the frontend and responding according to the expected system behaviors.
  • For simplification, I chose to not use a Service layer, so as I could cumulate the few existant business rules all within the Resource Layer, even being aware it is not a good practice.
  • The "Data access layer" is the interface UserRepository.java, which extends the JPA Repository class.
    • It's the sole logical layer interacting with the entity User, which is the file User.java, containg the core objects used throughout the application.

The rationale

graph TD
    A[Frontend Layer] -->|HTTP Request| B[Backend - Resource Layer]
    B --> C[Data Access Layer]
    C --> D[Postgres Database]
    C --> E[Entity Layer]
    
    %% Frontend Layer
    A[Frontend Layer]
    A --> A1[Bootstrap 5.3.3]
    A --> A2[JQuery 3.7.1]

    %% Backend - Resource Layer
    B[Backend - Resource Layer]
    B --> B1[UserResource.java]
    B1 -->|Receives Requests| B2[tb_users Table]
    
    %% Data Access Layer
    C[Data Access Layer]
    C --> C1[UserRepository.java]
    C1 -->|JPA Repository| C2[Spring Data JPA]
    
    %% Entity Layer
    E[Entity Layer]
    E --> E1[User.java]
    
    %% Backend Description
    subgraph Backend
        B
        C
        E
    end
    
    %% Database Layer
    D[Postgres Database]
    D -->|latest version in Docker Compose| D1[tb_users Table]

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How to use

About the Postgres database

No need to install a Postgres on your local machine. Simply use the provided docker-compose.yaml file. Change the database properties, volume, port and other settings as per your needs and run docker-compose up -d to start the database.

Using a database admin, such as Dbeaver (like I did) you can connect to the database pointing to the database port (using user and password etc.) as you set in the docker-compose.yaml file.

Running the project

Execute the DemoApplication.java or the Spring boot project on your favorite IDE and go to http://localhost:8081/crudproject/ to see the demo.

The project at a glance

• Empty state
  • 
• Search modal open with findAll() method invoked
  • 
• Search modal open with findByName() method invoked
  • 
• Exception treatment for deleting operation
  • 
• The Postgres table data being shown using DBeaver
  •