首先我們提供兩個類,基類為Parent,派生類為Child。在Parent中我們提供兩個方法,一個是靜態方法staticMethod(),一個是非靜態方法nonStaticMethod()。在Child
類中我們覆蓋著兩個方法。class Parent{
public void nonStaticMethod() {
System.out.println("Parent's Non-Static Method is Called");
}
public static void staticMethod() {
System.out.println("parent's static method is called");
}
}
class Child extends Parent{
public void nonStaticMethod() {
System.out.println("child's non-static method is called");
}
public static void staticMethod() {
System.out.println("child's static method is called");
}
}
在Test類中我們分別使用Parent p1 = new Parent(),Parent p2 = new Child(),Child c = new Child() 得到三個實例,并分別調用靜態方法和非靜態方法,我們來看程序的運行結果
在Test類中我們分別使用Parent p1 = new Parent(),Parent p2 = new Child(),Child c = new Child()得到三個實例,并分別調用靜態方法和非靜態方法,我們來看程序的運行結果public class Test{
public static void main(String args[]) {
Parent p1 = new Parent();
Parent p2 = new Child();
Child c = new Child();
System.out.print("Parent.static: ");
Parent.staticMethod();
System.out.print("p1.static: ");
p1.staticMethod();
System.out.print("p2.static: ");
p2.staticMethod();
System.out.print("p1.nonStatic: ");
p1.nonStaticMethod();
System.out.print("p2.nonStatic: ");
p2.nonStaticMethod();
System.out.print("Child.static: ");
Child.staticMethod();
System.out.print("c.static: ");
c.staticMethod();
System.out.print("c.nonStatic: ");
c.nonStaticMethod();
}
}
程序的運行結果為:
Parent.static: parent's static method is called
p1.static: parent's static method is called
p2.static: parent's static method is called
p1.nonStatic: Parent's Non-Static Method is Calle
p2.nonStatic: child's non-static method is called
Child.static: child's static method is called
c.static: child's static method is called
c.nonStatic: child's non-static method is called
值得注意的是p2實際上是一個Child的類型的引用,然而在調用靜態方法的時候,它執行的卻是父類的靜態方法,而不是Child的靜態方法,而調用 p2的非靜態方法的時候執行的是Child 的非靜態方法,為什么呢?原因是靜態方法是在編譯的時候把靜態方法和類的引用類型進行匹配,而不是在運行的時候和類引用進行匹配。因此我們得出結論:當我們在子類中創建的靜態方法,它并不會覆蓋父類中相同名字的靜態方法。