Guide: Connect MySQL from a Spring Java Project Deployed on Tomcat

This guide explains how to connect a Maven + Spring Java project (deployed on Apache Tomcat) to a local MySQL database running in XAMPP.

1. Start MySQL in XAMPP

Open XAMPP Control Panel (xampp-control.exe).
Start Apache and MySQL.
Open phpMyAdmin (http://localhost/phpmyadmin).

Create a database user and grant privileges, then create a sample database (animaldb) and table.

2. Create a Spring Project

Use Spring Initializer with:

Project: Maven
Language: Java
Dependencies: Spring Web, Spring Data JPA, Thymeleaf

3. Configure `application.properties`

spring.application.name=demo
spring.jpa.hibernate.ddl-auto=validate
spring.datasource.url=jdbc:mysql://${MYSQL_HOST:localhost}:3306/animaldb
spring.datasource.username=your_user
spring.datasource.password=your_password
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.jpa.database-platform=org.hibernate.dialect.MySQLDialect

4. Add Dependencies

If you use Maven, include the MySQL connector in pom.xml:

<dependency>
  <groupId>com.mysql</groupId>
  <artifactId>mysql-connector-j</artifactId>
  <version>9.2.0</version>
</dependency>

5. IntelliJ Database Connection

Community Edition

Open JPA Explorer.
Add a MySQL connection in DB Connections.
Test connection and download drivers if needed.

Ultimate Edition

Open View → Tool Windows → Database.
Use URL: jdbc:mysql://localhost:3306/animaldb.

6. Three-Layer Architecture

Typical layering:

Entity (Model)
Repository
Service
Controller
Thymeleaf views

7. Basic Example

Entity

@Entity
@Table(name = "animal")
public class Animal {
  @Id
  @GeneratedValue(strategy = GenerationType.IDENTITY)
  private Integer id;
 
  @Column(nullable = false)
  private String name;
 
  @Column(nullable = false)
  private Integer averageLifespan;
 
  @Column(nullable = false)
  private Boolean extinct;
}

Repository

@Repository
public interface AnimalRepository extends JpaRepository<Animal, Long> {
}

Service

@Service
public class AnimalService {
  @Autowired
  private AnimalRepository animalRepository;
 
  public List<Animal> getAll() {
    return animalRepository.findAll();
  }
}

Controller

@Controller
public class AnimalController {
  @Autowired
  private AnimalService animalService;
 
  @GetMapping("/animals")
  public String listAnimals(Model model) {
    model.addAttribute("animals", animalService.getAll());
    return "animals";
  }
}

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Connect MySQL from a Spring Java Project