Java接口
在java中如何解决在使用接口时而不实现所有的方法? 求实列。 java
[解决办法]
interface A{
public void fun1() ;
public void fun2() ;
}
//因为B类是抽象类，所以不能直接实例化
abstract class B implements A{
public void fun1(){
}
public void fun2(){
}
}
//C类只覆写B类的fun2()方法
class C extends B{
public void fun2(){
... //方法体
}
}
[解决办法]
/*
* Copyright (c) 1996, 2006, Oracle and/or its affiliates. All rights reserved.
* ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package java.awt.event;
/**
* An abstract adapter class for receiving mouse events.
* The methods in this class are empty. This class exists as
* convenience for creating listener objects.
* <P>
* Mouse events let you track when a mouse is pressed, released, clicked,
* moved, dragged, when it enters a component, when it exits and
* when a mouse wheel is moved.
* <P>
* Extend this class to create a {@code MouseEvent}
* (including drag and motion events) or/and {@code MouseWheelEvent}
* listener and override the methods for the events of interest. (If you implement the
* {@code MouseListener},
* {@code MouseMotionListener}
* interface, you have to define all of
* the methods in it. This abstract class defines null methods for them
* all, so you can only have to define methods for events you care about.)
* <P>
* Create a listener object using the extended class and then register it with
* a component using the component's {@code addMouseListener}
* {@code addMouseMotionListener}, {@code addMouseWheelListener}
* methods.
* The relevant method in the listener object is invoked and the {@code MouseEvent}
* or {@code MouseWheelEvent} is passed to it in following cases:
* <p><ul>
* <li>when a mouse button is pressed, released, or clicked (pressed and released)
* <li>when the mouse cursor enters or exits the component
* <li>when the mouse wheel rotated, or mouse moved or dragged
* </ul>
*
* @author Carl Quinn
* @author Andrei Dmitriev
*
* @see MouseEvent
* @see MouseWheelEvent
* @see MouseListener
* @see MouseMotionListener
* @see MouseWheelListener
* @see <a href="http://java.sun.com/docs/books/tutorial/post1.0/ui/mouselistener.html">Tutorial: Writing a Mouse Listener</a>
*
* @since 1.1
*/
public abstract class MouseAdapter implements MouseListener, MouseWheelListener, MouseMotionListener {
/**
* {@inheritDoc}
*/
public void mouseClicked(MouseEvent e) {}
/**
* {@inheritDoc}
*/
public void mousePressed(MouseEvent e) {}
/**
* {@inheritDoc}
*/
public void mouseReleased(MouseEvent e) {}
/**
* {@inheritDoc}
*/
public void mouseEntered(MouseEvent e) {}
/**
* {@inheritDoc}
*/
public void mouseExited(MouseEvent e) {}
/**
* {@inheritDoc}
* @since 1.6
*/
public void mouseWheelMoved(MouseWheelEvent e){}
/**
* {@inheritDoc}
* @since 1.6
*/
public void mouseDragged(MouseEvent e){}
/**
* {@inheritDoc}
* @since 1.6
*/
public void mouseMoved(MouseEvent e){}
}
