避免许多if语句的最好方法是什么？

// 基类
abstract class Shape {
    abstract void draw();
}

// 子类
class Circle extends Shape {
    void draw() {
        System.out.println("Drawing Circle");
    }
}

class Square extends Shape {
    void draw() {
        System.out.println("Drawing Square");
    }
}

// 使用
public class Main {
    public static void main(String[] args) {
        Shape shape = new Circle();
        shape.draw(); // 输出: Drawing Circle

        shape = new Square();
        shape.draw(); // 输出: Drawing Square
    }
}

// 策略接口
interface PaymentStrategy {
    void pay(int amount);
}

// 具体策略
class CreditCardPayment implements PaymentStrategy {
    public void pay(int amount) {
        System.out.println("Paid " + amount + " using Credit Card");
    }
}

class PayPalPayment implements PaymentStrategy {
    public void pay(int amount) {
        System.out.println("Paid " + amount + " using PayPal");
    }
}

// 上下文类
class ShoppingCart {
    private PaymentStrategy paymentStrategy;

    public void setPaymentStrategy(PaymentStrategy paymentStrategy) {
        this.paymentStrategy = paymentStrategy;
    }

    public void checkout(int amount) {
        paymentStrategy.pay(amount);
    }
}

// 使用
public class Main {
    public static void main(String[] args) {
        ShoppingCart cart = new ShoppingCart();
        cart.setPaymentStrategy(new CreditCardPayment());
        cart.checkout(100); // 输出: Paid 100 using Credit Card

        cart.setPaymentStrategy(new PayPalPayment());
        cart.checkout(200); // 输出: Paid 200 using PayPal
    }
}

import java.util.HashMap;
import java.util.Map;
import java.util.function.Consumer;

public class Main {
    public static void main(String[] args) {
        Map<String, Consumer<String>> operations = new HashMap<>();
        operations.put("add", s -> System.out.println("Adding " + s));
        operations.put("subtract", s -> System.out.println("Subtracting " + s));
        operations.put("multiply", s -> System.out.println("Multiplying " + s));

        String operation = "add";
        String value = "10";

        if (operations.containsKey(operation)) {
            operations.get(operation).accept(value);
        } else {
            System.out.println("Unsupported operation");
        }
    }
}

public class Main {
    public static void main(String[] args) {
        String day = "Monday";

        switch (day) {
            case "Monday":
                System.out.println("Today is Monday");
                break;
            case "Tuesday":
                System.out.println("Today is Tuesday");
                break;
            default:
                System.out.println("Unknown day");
        }
    }
}

def process_data(data, func):
    return func(data)

def add_one(data):
    return data + 1

def multiply_by_two(data):
    return data * 2

data = 5
result = process_data(data, add_one)
print(result)  # 输出: 6

result = process_data(data, multiply_by_two)
print(result)  # 输出: 10