享元模式java实例

好的，下面是享元模式的一个简单的 Java 实例：

import java.util.HashMap;

public class FlyweightFactory {
    private static final HashMap<String, Flyweight> flyweights = new HashMap<>();

    public static Flyweight getFlyweight(String key) {
        Flyweight flyweight = flyweights.get(key);

        if (flyweight == null) {
            flyweight = new ConcreteFlyweight();
            flyweights.put(key, flyweight);
        }

        return flyweight;
    }
}

public interface Flyweight {
    void operation();
}

public class ConcreteFlyweight implements Flyweight {
    @Override
    public void operation() {
        System.out.println("ConcreteFlyweight operation");
    }
}

public class Client {
    public static void main(String[] args) {
        Flyweight flyweight1 = FlyweightFactory.getFlyweight("key1");
        Flyweight flyweight2 = FlyweightFactory.getFlyweight("key1");

        flyweight1.operation();
        flyweight2.operation();

        System.out.println(flyweight1 == flyweight2);
    }
}

在这个例子中，`FlyweightFactory` 是享元工厂类，用于创建和管理享元对象。`Flyweight` 是享元接口，定义了享元对象的操作。`ConcreteFlyweight` 是具体的享元实现类，实现了 `Flyweight` 接口。`Client` 是客户端类，用于测试享元模式。

在 `Client` 类中，我们通过 `FlyweightFactory.getFlyweight()` 方法获取享元对象，并调用其 `operation()` 方法执行操作。由于我们获取的是同一个 key 对应的享元对象，因此它们的引用相同，输出结果为 `true`。