1永毅、訪問修飾符access modifier：
1）public 修飾的方法和屬性可被所有類訪問
2）protected 可在類內(nèi)部人弓、相同包、該類的子類所訪問
3）private 只能在該類內(nèi)部使用
4）默認(rèn)的：在類內(nèi)部及相同包下面的類使用
例一：相同包內(nèi)
package com.shengsiyuan;
public class C
{
protected int year = 2016;
}
package com.shengsiyuan;
public class D
{
public static void main(String[] args)
{
C c = new C();
System.out.println(c.year);
}
}
例二：該類的子類訪問
package com.shengsiyuan;
public class C
{
protected int year = 2016;
}
package com.shengsiyuan.test;
import com.shengsiyuan.C;
public class D extends C
{
public void output()
{
System.out.println(year);
}
public static void main(String[] args)
{
D d = new D();
d.output();
}
}
2滨嘱、instanceof:判斷某個(gè)對(duì)象是否是某個(gè)類的實(shí)例。
public class InstanceofTest
{
public static void main(String[] args)
{
People people = new People();
System.out.println(people instanceof People);
}
}
class People
{
}
public class InstanceofTest
{
public static void main(String[] args)
{
People people = new Man();
System.out.println(people instanceof People);//結(jié)果為true.
}
}
class People
{
}
class Man extends People
{
}
