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📁 java程序员必读基础篇
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                  <div align="center" class="title">JAVA程序员必读：基础篇（2）面向对象编程概念</div>
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                  <div align="right" class="gray">&nbsp;&nbsp;&nbsp;&nbsp;</div>
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                  <div align="center"><font color="#666666">编译：ZSC/太平洋网络学院</font></div>
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                  <div align="right" class="gray"><a href="mailto:tntst@pconline.com.cn">［责编:爆破手］</a></div>
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            <p><b><span class="article">2.4实例和类成员</span></b></p>
            <b><span class="article">2.4.5 对象和类</span></b> 
            <p class="article"> 　　你可能会注意到对象和类看起来很相似。在现实世界中，类和对象之间的区别经常是让程序员困惑的源泉。在现实世界中，很明显，类不能是它们描述的对象本身。然而，在软件中很困难来区分类和对象。有部分原因是软件对象只是现实世界中的电子模型或者是抽象概念。但是也因为对象通常有时是指类和实例。</p>
            <p></p>
            <p class="article"><b>2.5什么是继承</b></p>
            <p class="article"> 　　一个类可以从它的父类继承状态和行为。继承为组织和构造软件程序提供了一个强大的和自然的机理。</p>
            <p class="article"> 　　总得说来，对象是以类得形式来定义得。你可能现在已经可以从它类知道许多对象了。即使你如知道，如果我告诉你它是一辆自行车，你就会知道它有两个轮子和脚踏板等等。面向对象系统就更深入一些了，它允许类在其它类中定义。比如，山地自行车、赛车以及串座双人自行车都是各种各样的自行车。在面向对象技术中，山地自行车、赛车以及串座双人自行车都是自行车类的子类。同样地，自行车类是山地自行车、赛车以及串座双人自行车的父类。这个父子关系可以如图9所示：</p>
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            <p class="article"><img src="../images/10717/Image47.gif" width=365 height=281></p>
            <p class="article">（图9）</p>
            <p class="article"> 　　每一个子例从父类中继承了状态。山地自行车、赛车以及串座双人自行车共享了这些状态：速度等。同样，每一个子类继承类从父类的方法，山地自行车、赛车以及串座双人自行车共享了这些行为：刹车、改变脚踏速度等等。</p>
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