Spring Boot Quickstart

Spring Boot Quickstart

1. Install Prerequisites

Make sure you have the following installed:

• Java Development Kit (JDK): Version 8 or higher. Check if it's installed:

bash java -version

Download it from oracle.com if necessary.

• Maven: A build tool for Java projects. Check if it's installed:

bash mvn -version

Download it from maven.apache.org if needed.

2. Create a New Spring Boot Project

Use the Spring Initializr to generate a new Spring Boot project:

1. Go to start.spring.io.
2. Choose Maven Project.
3. Select your preferred Java version.
4. Fill in the Group and Artifact (e.g., com.example and demo).
5. Select Dependencies:
6. Spring Web
7. Spring Data JPA
8. H2 Database (for an in-memory database)
9. Click Generate to download a ZIP file containing your project.

3. Extract and Navigate to Your Project

Unzip the downloaded file and navigate to the project directory:

cd demo

4. Open the Project in Your IDE

Open the project in your favorite IDE (like IntelliJ IDEA or Eclipse). If using IntelliJ, import the project as a Maven project.

5. Create a Simple Model

In src/main/java/com/example/demo, create a class called Item.java:

package com.example.demo;

import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;

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

    // Getters and setters
    public Long getId() { return id; }
    public void setId(Long id) { this.id = id; }
    public String getName() { return name; }
    public void setName(String name) { this.name = name; }
    public String getDescription() { return description; }
    public void setDescription(String description) { this.description = description; }
}

6. Create a Repository

Create an interface called ItemRepository.java:

package com.example.demo;

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

public interface ItemRepository extends JpaRepository<Item, Long> {
}

7. Create a Controller

Create a class called ItemController.java:

package com.example.demo;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.*;

import java.util.List;

@RestController
@RequestMapping("/items")
public class ItemController {

    @Autowired
    private ItemRepository itemRepository;

    @GetMapping
    public List<Item> getAllItems() {
        return itemRepository.findAll();
    }

    @PostMapping
    public Item createItem(@RequestBody Item item) {
        return itemRepository.save(item);
    }
}

8. Run the Application

Run the main class located at src/main/java/com/example/demo/DemoApplication.java:

package com.example.demo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;

@SpringBootApplication
public class DemoApplication {
    public static void main(String[] args) {
        SpringApplication.run(DemoApplication.class, args);
    }
}

You can run the application via your IDE or using Maven:

mvn spring-boot:run

9. Test Your API with Postman

GET All Items:

1. Open Postman.
2. Set the request type to GET.
3. Enter the URL: http://localhost:8080/items.
4. Click Send.
5. You should see an empty array ([]) as no items have been added yet.

POST a New Item:

1. Change the request type to POST.
2. Enter the URL: http://localhost:8080/items.
3. Go to the Body tab.
4. Select raw and choose JSON from the dropdown.
5. Enter the following JSON:

json { "name": "Item1", "description": "This is Item 1" }

1. Click Send.
2. You should see the created item in the response, including its ID.

Verify Item Creation:

1. Set the request type to GET.
2. Enter the URL: http://localhost:8080/items.
3. Click Send.
4. You should see the list with your newly created item.

Conclusion

You've successfully created a Spring Boot application with a model, repository, and RESTful controller. You also tested your API using Postman.

For more detailed documentation, visit the official Spring Boot documentation at spring.io. Happy coding!