Java 范例 - 方法覆盖
方法重载与方法覆盖区别如下
- 方法重载(Overloading): 如果有两个方法的方法名相同,但参数不一致,哪么可以说一个方法是另一个方法的重载
- 方法覆盖(Overriding): 如果在子类中定义一个方法,其名称、返回类型及参数签名正好与父类中某个方法的名称、返回类型及参数签名相匹配,那么可以说,子类的方法覆盖了父类的方法
下面的范例演示了 Java 方法覆盖 ( Overriding ) 代码的实现
public class Findareas{ public static void main (String []agrs){ Figure f= new Figure(10 , 10); Rectangle r= new Rectangle(9 , 5); Figure figref; figref=f; System.out.println("Area is :"+figref.area()); figref=r; System.out.println("Area is :"+figref.area()); } } class Figure{ double dim1; double dim2; Figure(double a , double b) { dim1=a; dim2=b; } Double area() { System.out.println("Inside area for figure."); return(dim1*dim2); } } class Rectangle extends Figure { Rectangle(double a, double b) { super(a ,b); } Double area() { System.out.println("Inside area for rectangle."); return(dim1*dim2); } }
编译运行以上 Java 代码,输出结果如下
Inside area for figure. Area is :100.0 Inside area for rectangle. Area is :45.0