BERT-CRF 微调中文 NER 模型

                                     设计模式（分类）        设计模式（六大原则）   

    创建型（5种）        工厂方法         抽象工厂模式        单例模式        建造者模式        原型模式

    结构型（7种）        适配器模式        装饰器模式        代理模式        ​​​​​​外观模式      桥接模式        组合模式       享元模式

    行为型（11种）      策略模式        模板方法模式        观察者模式        迭代器模式        责任链模式        命令模式

                                   备忘录模式          状态模式          访问者模式        中介者模式

设计模式中的策略模式（Strategy Pattern）是一种行为设计模式，它定义了一系列算法，并将每个算法封装在一个单独的类中，使得它们可以互相替换。策略模式使得算法可以在运行时根据需要动态地改变，同时客户端代码可以通过统一的接口调用不同的策略实现。

模式结构

工作原理

优缺点

优点

缺点

适用场景

代码示例（以Java为例）

// 抽象策略接口
public interface DiscountStrategy {
    double getDiscount(double price);
}

// 具体策略类 - 无折扣策略
public class NoDiscountStrategy implements DiscountStrategy {
    @Override
    public double getDiscount(double price) {
        return price;
    }
}

// 具体策略类 - 普通会员折扣策略
public class NormalMemberDiscountStrategy implements DiscountStrategy {
    @Override
    public double getDiscount(double price) {
        return price * 0.95; // 九五折
    }
}

// 具体策略类 - VIP会员折扣策略
public class VIPDiscountStrategy implements DiscountStrategy {
    @Override
    public double getDiscount(double price) {
        return price * 0.85; // 八五折
    }
}

// 上下文类 - 订单类，使用策略来计算折扣后的价格
public class Order {
    private DiscountStrategy discountStrategy;

    public Order(DiscountStrategy discountStrategy) {
        this.discountStrategy = discountStrategy;
    }

    public void setDiscountStrategy(DiscountStrategy discountStrategy) {
        this.discountStrategy = discountStrategy;
    }

    public double calculateFinalPrice(double originalPrice) {
        return discountStrategy.getDiscount(originalPrice);
    }
}

// 客户端代码
public class Client {
    public static void main(String[] args) {
        Order orderWithoutDiscount = new Order(new NoDiscountStrategy());
        System.out.println("No discount applied: " + orderWithoutDiscount.calculateFinalPrice(100));

        Order normalOrder = new Order(new NormalMemberDiscountStrategy());
        System.out.println("Normal member discount applied: " + normalOrder.calculateFinalPrice(100));

        Order vipOrder = new Order(new VIPDiscountStrategy());
        System.out.println("VIP member discount applied: " + vipOrder.calculateFinalPrice(100));
    }
}

代码示例（以Python为例）

# 策略接口
from abc import ABC, abstractmethod

class PaymentStrategy(ABC):
    @abstractmethod
    def pay(self, amount: float) -> None:
        pass

# 具体策略类
class CreditCardPayment(PaymentStrategy):
    def __init__(self, card_number: str, cvv: str):
        self.card_number = card_number
        self.cvv = cvv

    def pay(self, amount: float) -> None:
        print(f"Paid {amount} using credit card ({self.card_number})")

class PayPalPayment(PaymentStrategy):
    def __init__(self, account_id: str):
        self.account_id = account_id

    def pay(self, amount: float) -> None:
        print(f"Paid {amount} using PayPal account ({self.account_id})")

# 上下文
class ShoppingCart:
    def __init__(self, payment_strategy: PaymentStrategy):
        self.payment_strategy = payment_strategy

    def set_payment_strategy(self, strategy: PaymentStrategy) -> None:
        self.payment_strategy = strategy

    def checkout(self, total_amount: float) -> None:
        print(f"Checking out with total amount: {total_amount}")
        self.payment_strategy.pay(total_amount)

# 客户端代码
cart = ShoppingCart(CreditCardPayment("1234567890123456", "123"))
cart.checkout(100.00)

cart.set_payment_strategy(PayPalPayment("buyer@example.com"))
cart.checkout(200.00)

在这个示例中：