java繼承之變量

子類可以繼承父類的protected、default、public變量。而private不能繼承。這個很簡單，直接看代碼。

package extend; public class ParentClass { private String privateVariable = "private Variable"; protected String protectedVariable = "protected Variable"; String defaultVariable = "default Variable"; public String publicVariable = "public Variable"; private static String privateStaticVariable = "private Static Variable"; protected static String protectedStaticVariable = "protected Static Variable"; static String defaultStaticVariable = "dafault Static Variable"; public static String publicStaticVariable = "publicStatic Variable"; public ParentClass() { System.out.println("default parent class"); } public ParentClass(String str) { System.out.println("parent class " + str); } } public class SubClass extends ParentClass { public SubClass(){ System.out.println("default sub class"); // System.out.println("sub class print : " + privateVariable); System.out.println("sub class print : " + protectedVariable); System.out.println("sub class print : " + defaultVariable); System.out.println("sub class print : " + publicVariable); // System.out.println("sub class print : " + privateStaticVariable); System.out.println("sub class print : " + protectedStaticVariable); System.out.println("sub class print : " + defaultStaticVariable); System.out.println("sub class print : " + publicStaticVariable); } public SubClass(String str){ super(str); System.out.println("sub class " + str); } public static void main(String[] args) { SubClass subClass = new SubClass(); new SubClass("A"); } } 

 

運行結果:

default parent class

default sub class

sub class print : protected Variable

sub class print : default Variable

sub class print : public Variable

sub class print : protected Static Variable

sub class print : dafault Static Variable

sub class print : publicStatic Variable parent

class A

sub class A

代碼導讀：

在父類中定義private,protected,default,public變量。在子類中直接訪問。

結論：

從運行結果可以得到， 在子類中可以直接訪問protected,default,public屬性。子類直接把父類的這三種變量當成自己的變量了。呵呵。父類的private變量可以通過getter和setter方法訪問。