Java特性和设计模式的关系?

来源:互联网 发布:东盟交易所软件 编辑:程序博客网 时间:2024/06/06 08:59

自己学习的时候,经常疑惑什么是设计模式,设计模式是怎么实现的,后来深思后明白,设计模式就是Java的特性(继承,封装,多态,静态,接口,反射)等,利用一种或几种按照一定的规律编码,就是设计模式。例如:

代理模式:就是利用多态,反射,以及接口三大特性。



1:接口
public interface Subject {
    void visit();
}


public class RealSubject implements Subject {


    private String name = "byhieg";
    @Override
    public void visit() {
        System.out.println(name);
    }
}


静态代理:
public class ProxySubject implements Subject{


    private Subject subject;


    public ProxySubject(Subject subject) {
        this.subject = subject;
    }


    @Override
    public void visit() {
        subject.visit();
    }
}


静态代理调用:
public class Client {


    public static void main(String[] args) {
        ProxySubject subject = new ProxySubject(new RealSubject());
        subject.visit();
    }
}


动态代理:
public class DynamicProxy implements InvocationHandler {
    private Object object;
    public DynamicProxy(Object object) {
        this.object = object;
    }




@Override
public Object invoke(Object proxy, Method method, Object[] args) throws Throwable {
        Object result = method.invoke(object, args);
        return result;
    }
}


动态代理调用
Subject realSubject = new RealSubject();
DynamicProxy proxy = new DynamicProxy(realSubject);
ClassLoader classLoader = realSubject.getClass().getClassLoader();
Subject subject = (Subject) Proxy.newProxyInstance(classLoader, new  Class[]{Subject.class}, proxy);
subject.visit();