num14---享元模式

Posted 2021-03-09 dxxdsw

 

 

 

 

 

 

 

 案例：

 

 

 

 

public abstract class WebSite {

	public abstract void use(User user);//抽象方法
}

　　

public class ConcreteWebSite extends WebSite {
	private String type = ""; //网站发布形式（类型）

	public ConcreteWebSite(String type) {
		this.type = type;
	}

	@Override
	public void use(User user) {
		System.out.println("网站发布形式:" + type + " 使用者：" + user.getName());
	}
}

　　

public class User {
	
	private String name;
	
	public User(String name) {
		super();
		this.name = name;
	}
	public String getName() {
		return name;
	}

	public void setName(String name) {
		this.name = name;
	}
}

　

// 网站工厂类
public class WebSiteFactory {
	
	//集合，充当池的作用
	private HashMap<String, ConcreteWebSite> pool = new HashMap<>();
	
	//根据网站类型返回网站
	public WebSite getWebSiteCategory(String type) {
		if(!pool.containsKey(type)) {
			pool.put(type, new ConcreteWebSite(type));
		}
		return (WebSite)pool.get(type);
	}
	
	//获取池中数量
	public int getWebSiteCount() {
		return pool.size();
	}
}

　　

public static void main(String[] args) {

		// 创建一个工厂类
		WebSiteFactory factory = new WebSiteFactory();

		WebSite webSite1 = factory.getWebSiteCategory("新闻");
		webSite1.use(new User("tom"));
		
		WebSite webSite2 = factory.getWebSiteCategory("博客");
		webSite2.use(new User("jack"));

		WebSite webSite3 = factory.getWebSiteCategory("博客");
		webSite3.use(new User("smith"));

		WebSite webSite4 = factory.getWebSiteCategory("博客");
		webSite4.use(new User("king"));
		
		System.out.println("容量=" + factory.getWebSiteCount());
	}