CRUD Operations in Spring Boot with H2 Database

October 12, 2025

#1

This guide shows how to perform CRUD operations in a Spring Boot project using the H2 in-memory database for fast development.

1. Add Dependency

In pom.xml:

<dependency>
  <groupId>com.h2database</groupId>
  <artifactId>h2</artifactId>
  <scope>runtime</scope>
</dependency>
<dependency>
  <groupId>org.springframework.boot</groupId>
  <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>

2. Configure H2

application.properties:

spring.datasource.url=jdbc:h2:mem:testdb
spring.datasource.driver-class-name=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=
spring.jpa.hibernate.ddl-auto=update
spring.h2.console.enabled=true

3. Create Entity

import jakarta.persistence.*;

@Entity
public class Student {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;
    private String name;
    private String email;
}

4. Repository

import org.springframework.data.jpa.repository.JpaRepository;

public interface StudentRepository extends JpaRepository<Student, Long> {
}

5. Controller

import org.springframework.web.bind.annotation.*;
import java.util.List;

@RestController
@RequestMapping("/students")
public class StudentController {
    private final StudentRepository repo;

    public StudentController(StudentRepository repo) {
        this.repo = repo;
    }

    @PostMapping
    public Student create(@RequestBody Student student) {
        return repo.save(student);
    }

    @GetMapping
    public List<Student> getAll() {
        return repo.findAll();
    }

    @GetMapping("/{id}")
    public Student getOne(@PathVariable Long id) {
        return repo.findById(id).orElse(null);
    }

    @PutMapping("/{id}")
    public Student update(@PathVariable Long id, @RequestBody Student s) {
        return repo.findById(id)
            .map(st -> {
                st.setName(s.getName());
                st.setEmail(s.getEmail());
                return repo.save(st);
            }).orElse(null);
    }

    @DeleteMapping("/{id}")
    public void delete(@PathVariable Long id) {
        repo.deleteById(id);
    }
}

6. Test the API

Start the app:

mvn spring-boot:run

Test endpoints with Postman or curl:

• POST /students → create
• GET /students → read all
• GET /students/{id} → read one
• PUT /students/{id} → update
• DELETE /students/{id} → delete