🆔 @javapro_ir
🆔 @group_javapro

🆔 @javapro_ir
🆔 @group_javapro

🆔 @javapro_ir
🆔 @group_javapro

🆔 @javapro_ir
🆔 @group_javapro

public class Car {
    public static int totalCars = 0;  // Static
    private String model;             // Instance

    public Car(String model) {
        this.model = model;
        totalCars++;
    }

    public String getModel() {
        return model;
    }
}

Car c1 = new Car("BMW");
Car c2 = new Car("Audi");

System.out.println(Car.totalCars);  // 2
System.out.println(c1.getModel());  // BMW
System.out.println(c2.getModel());  // Audi

double result = Math.sqrt(25);  // بدون ایجاد شیء

#کاربر_مبتدی

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🆔 @group_javapro

🆔 @javapro_ir
🆔 @group_javapro

هیچ‌وقت برای هزینه‌ای که صرف رشد و پیشرفت خودت می‌کنی تردید و دودوتاچهارتا نکن.

🆔 @javapro_ir
🆔 @group_javapro

@Service
public class MessageService {

    private final Messenger messenger;

    public MessageService(Messenger messenger) {
        this.messenger = messenger;
    }

    public void send() {
        messenger.sendMessage("Hello Spring");
    }
}

mvn spring-boot:run

#Spring

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🆔 @javapro_ir
🆔 @group_javapro

src
 └── main
      ├── java
      │    └── com.example.demo
      │           ├── DemoApplication.java
      │           ├── controller
      │           ├── service
      │           └── repository
      └── resources
           ├── application.properties
           └── static / templates

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

mvn spring-boot:run

https://localhost:8080

@RestController
public class HelloController {

    @GetMapping("/hello")
    public String hello() {
        return "Hello Spring Boot!";
    }
}

#Spring

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@RestController
@RequestMapping("/users")
public class UserController {

    private final UserService userService;

    public UserController(UserService userService) {
        this.userService = userService;
    }

    @GetMapping("/{id}")
    public User getUser(@PathVariable Long id) {
        return userService.getUserById(id);
    }
}

@Service
public class UserService {

    private final UserRepository userRepository;

    public UserService(UserRepository userRepository) {
        this.userRepository = userRepository;
    }

    public User getUserById(Long id) {
        return userRepository.findById(id)
                .orElseThrow(() -> new RuntimeException("User not found"));
    }
}

@Repository
public interface UserRepository extends JpaRepository<User, Long> {
}

#Spring

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🆔 @group_javapro

@Component
public class EmailSender {
    public void send() {
        System.out.println("Sending email...");
    }
}

@Service
public class NotificationService {

    private final EmailSender emailSender;

    public NotificationService(EmailSender emailSender) {
        this.emailSender = emailSender;
    }

    public void notifyUser() {
        emailSender.send();
    }
}

#Spring

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🆔 @group_javapro

🆔 @javapro_ir
🆔 @group_javapro