Java课件第六讲Java面向对象程序设计.ppt

第6讲 Java 面向对象程序设计面向对象的程序设计方法按照现实世界的特点,把复杂的事务抽象为对象。对象具有自己的状态和行为,通过对消息的反应来完成一定的任务。面向对象是 Java 的重要特性。 Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 一、 Java 面向对象基础 Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. (一) 类的定义 Java 的类是由类声明和类体二部分构成, 类声明定义的格式如下: [类修饰符] class 类名 [extends 父类名] [implements 接口名, [接口名]] { 类体} 例: public class HelloWorldApp { public static void main(String args[]) { ( “ HelloWorld! ”); } } Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 类体定义的格式: class 类名 { 变量声明; 方法声明; } 例: class Point { int x,y; void init(int ix,int iy) { x=ix; y=iy; } } Evaluation only. Evaluation only. Created with Client Profile . Created with Client Profile . Copyright 2004-2011 Aspose Pty Ltd. Copyright 2004-2011 Aspose Pty Ltd. 例: public class Calculator{ private double result; public double a,b; public double Calculator(){ result=0; } public double Add(){ result=a+b; return result; } public double Minus(){ result=a-b; return result; } } Evaluation only. Evaluation only. Created with Client Profile . Created with for .