Masoud Hamad

Lab 6 — Students API (beginner edition)

The simplest possible Spring Boot REST API. Three layers, one file each, ~4 Java files total. Use this as your starting point — lab06_students_api/ is the production-grade version you can graduate to later.

What’s inside

src/main/java/tz/ac/suza/wt/studentsapi/
├── StudentsApiApplication.java   # main()
├── entity/Student.java           # the table
├── repository/StudentRepository.java   # CRUD comes free
└── controller/StudentController.java   # the 5 endpoints

No DTOs. No service layer. No @RestControllerAdvice. No Docker. No tests. No Swagger. Just enough to see CRUD work end to end.

Prerequisites

• JDK 21 — see windows_jdk_maven_setup.md on Windows.
• Maven.
• A local PostgreSQL (Postgres.app on macOS, the installer on Windows, apt install postgresql on Linux).

Run it

1. Create the database and user (once)

psql -d postgres -c "CREATE USER studentsapi WITH PASSWORD 'studentsapi';"
psql -d postgres -c "CREATE DATABASE studentsdb OWNER studentsapi;"

2. Run the app

mvn spring-boot:run

The app boots on http://localhost:8080. Hibernate creates the students table on first run.

3. Try it

curl -s http://localhost:8080/api/students

Empty array on first run — that’s correct.

curl -s -X POST http://localhost:8080/api/students \
  -H 'Content-Type: application/json' \
  -d '{"name":"Asha","email":"asha@example.com","course":"BCS","year":2}'

You get back the created student with an id. Now GET /api/students returns one item.

Open requests.http in VS Code (REST Client extension) for the full set.

The 5 endpoints

Method	URL	What it does
GET	/api/students	List all
GET	/api/students/{id}	Get one
POST	/api/students	Create
PUT	/api/students/{id}	Update
DELETE	/api/students/{id}	Delete

Where to go next

When this version makes sense, study ../lab06_students_api/ and the full walkthrough — same API, but with DTOs, a service layer, global error handling, Docker, and Swagger. Same problem, production-grade.