二十三种设计模式全面解析-享元模式（Flyweight Pattern）详解：构建高效共享的对象结构

import java.util.HashMap;
import java.util.Map;
// 享元接口
interface Flyweight {
    void render(String externalState);
}
// 具体享元类
class ConcreteFlyweight implements Flyweight {
    private String intrinsicState;
    public ConcreteFlyweight(String intrinsicState) {
        this.intrinsicState = intrinsicState;
    }
    @Override
    public void render(String externalState) {
        System.out.println("Intrinsic State: " + intrinsicState);
        System.out.println("External State: " + externalState);
        // 执行享元对象的渲染操作
    }
}
// 享元工厂
class FlyweightFactory {
    private Map<String, Flyweight> flyweights = new HashMap<>();
    public Flyweight getFlyweight(String key) {
        Flyweight flyweight = flyweights.get(key);
        if (flyweight == null) {
            flyweight = new ConcreteFlyweight(key);
            flyweights.put(key, flyweight);
        }
        return flyweight;
    }
}
// 客户端
public class Client {
    public static void main(String[] args) {
        FlyweightFactory factory = new FlyweightFactory();
        Flyweight flyweight1 = factory.getFlyweight("A");
        flyweight1.render("External State 1");
        Flyweight flyweight2 = factory.getFlyweight("B");
        flyweight2.render("External State 2");
        Flyweight flyweight3 = factory.getFlyweight("C");
        flyweight3.render("External State 3");
        // 输出：
        // Intrinsic State: A
        // External State: External State 1
        // Intrinsic State: B
        // External State: External State 2
        // Intrinsic State: C
        // External State: External State 3
    }
}