Spring CRUD Example

The simple example of creating a CRUD (Create, Read, Update, Delete) application using Spring Boot. This example demonstrates how to create a basic web application to manage a list of “items” using Spring Data JPA and Thymeleaf templating engine.

1. Create a Spring Boot Project:

Start by creating a new Spring Boot project using Spring Initializr or your preferred development environment.

2. Define the Item Entity:

Create an Item entity class with fields for an ID, name, and description.

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
}

3. Create a Repository:

Create a repository interface for the Item entity by extending JpaRepository.

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

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

4. Implement CRUD Controller:

Create a controller that handles CRUD operations for the Item entity.

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.*;

@Controller
@RequestMapping("/items")
public class ItemController {
    @Autowired
    private ItemRepository itemRepository;

    @GetMapping
    public String listItems(Model model) {
        model.addAttribute("items", itemRepository.findAll());
        return "items/list";
    }

    @GetMapping("/new")
    public String newItemForm(Model model) {
        model.addAttribute("item", new Item());
        return "items/new";
    }

    @PostMapping
    public String createItem(Item item) {
        itemRepository.save(item);
        return "redirect:/items";
    }

    // Implement update and delete methods
}

5. Create HTML Templates:

Create Thymeleaf templates for listing items, creating new items, updating items, and displaying item details.

• src/main/resources/templates/items/list.html
• src/main/resources/templates/items/new.html
• src/main/resources/templates/items/edit.html
• src/main/resources/templates/items/details.html

These templates will use Thymeleaf to display and interact with the data.

6. Configure Application Properties:

Configure your database connection and other properties in src/main/resources/application.properties or application.yml.

spring.datasource.url=jdbc:mysql://localhost:3306/mydb
spring.datasource.username=root
spring.datasource.password=
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.jpa.hibernate.ddl-auto=update

7. Run the Application:

Run your Spring Boot application. You should be able to access the CRUD functionality through your browser at http://localhost:8080/items.

This example provides a basic overview of setting up a CRUD application using Spring Boot, Spring Data JPA, and Thymeleaf. Depending on your requirements, you can enhance the application by adding validation, security, pagination, error handling, and more.