[Java x Spring Boot] A complete guide to creating a business system | Includes MySQL integration and practical code!

programming

"I'm interested in Spring Boot, but it seems difficult."
"Where do I start when creating a business system?"
For those who have such concerns.

In this article,Java×Spring Boot business inventory management systemThe steps to build it from scratch are as follows:
Explanations that are easy to understand even for beginnersI will.

Including linking with MySQL and data storage processing,Basic methods that can be used on-siteYou can learn.

What can you do with Spring Boot?

Meet the requirements for a business system

Conclusion: Spring Boot allows you to create business applications efficiently and safely.

The business system needs the following:

  • Registering, editing, and deleting data (CRUD function)
  • Connecting to a database (e.g. MySQL)
  • Stable routing structure
  • Code reusability and maintainability

Spring Boot provides a mechanism to build these elements in a short time.
GovernmentInformation System Construction StandardsBut there is a need for a robust and maintainable design.
(Reference: Digital Agency https://www.digital.go.jp/policies/cloud-by-default/)

Project configuration and preparation

First, create a project with Spring Initializr.

Conclusion: Create a basic configuration on the official site and set up MySQL connection.

Preparation steps:

  • Visit https://start.spring.io/
  • Select the following settings:
  • Project: Maven
  • Language: Java
  • Dependencies: Spring Web, Spring Data JPA, MySQL Driver
  • After downloading, extract it in your favorite IDE (e.g. IntelliJ, VSCode)

next,application.propertiesSet it as follows:

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spring.datasource.url=jdbc:mysql://localhost:3306/inventory_db spring.datasource.username=root spring.datasource.password=password spring.jpa.hibernate.ddl-auto=update spring.jpa.show-sql=true

Database and Entity Design

Map a MySQL table to a Java class

Bottom line: Create Java classes to match your table structure.

Example: Product table "products"

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CREATE TABLE products ( id INT AUTO_INCREMENT PRIMARY KEY, name VARCHAR(100), price INT );

Entity class (Product.java)

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import jakarta.persistence.*; @Entity public class Product { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) public int id; public String name; public int price; }

Implementing Data Operations: Repositories and Controllers

Allows you to list, register and delete product information

Conclusion: Using JPA functions, you can operate without writing SQL.

Repository interface (ProductRepository.java)

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import org.springframework.data.jpa.repository.JpaRepository; public interface ProductRepository extends JpaRepository {}

Controller (ProductController.java)

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import org.springframework.beans.factory.annotation.Autowired; import org.springframework.web.bind.annotation.*; import java.util.List; @RestController @RequestMapping("/products") public class ProductController { @Autowired private ProductRepository repo; @GetMapping public List list() { return repo.findAll(); } @PostMapping public Product add(@RequestBody Product p) { return repo.save(p); } @DeleteMapping("/{id}") public void delete(@PathVariable int id) { repo.deleteById(id); } }

Common errors and solutions

Here are some common errors and how to fix them

  • Error: Unknown database 'inventory_db'
    → Solution: Log in to MySQL,CREATE DATABASE inventory_db; Run
  • Error: Access denied for user 'root'@'localhost'
    → Solution:application.properties Check that the password and user name are correct.
  • Error: Entity class not recognized
    → Solution:@EntityScanCheck annotations and correct package configuration

Application functions and advanced examples

Meet commercial-level requirements

Additional features can easily be implemented, such as:

  • Update function (PUTAdding a method
  • Input value check (@Validand validation annotations)
  • Login function (Spring Security)
  • Pagination support (Pageableuse)

Summary of the completed configuration

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src/ ├─ Product.java ├─ ProductRepository.java ├─ ProductController.java └─ application.properties

Example of operation check URL:

  • GET http://localhost:8080/products
  • POST http://localhost:8080/products
  • DELETE http://localhost:8080/products/{id}

Summary: You can create your own business systems

In this article,MySQL-linked business system using Java and Spring BootI explained how to build it.

What I learned:

  • Spring Boot project configuration and startup method
  • Database operations with JPA
  • Basic implementation of REST API

By further developing this technology, it will be possible to develop apps that can be used in practical applications.

please,Custom business systemTry building it!

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