Java接口详解：从RemoteControl到OrderService，轻松掌握接口设计与实现

public interface RemoteControl {

void powerOn();
void powerOff();
void volumeUp();
void volumeDown();

}

public interface DataProcessor {

void process(String data);

default void validate(String data) {
    if (data == null || data.trim().isEmpty()) {
        throw new IllegalArgumentException("数据不能为空");
    }
}

default String getVersion() {
    return "v2.0";
}

}

// 订单服务接口 public interface OrderService {

Order createOrder(CreateOrderRequest request);
Order getOrder(String orderId);
void cancelOrder(String orderId);

}

// 支付服务接口
public interface PaymentService {

PaymentResult processPayment(PaymentRequest request);
PaymentStatus getPaymentStatus(String paymentId);

}