权限修饰符(public、protected、default、private)权限验证
一、测试方法
在authorityTest包中建类AuthorityValidate
package authorityTest; public class AuthorityValidate { private String authority1 = "private"; protected String authority2 = "protected"; private void runPrivate(String a) { System.out.print(a); } protected void runProtectde(String b) { System.out.print(b); System.out.print(authority1); } }
在authorityTest包中建立TheThirdClass类并尝试调用AuthorityValidate 中不同权限的方法
package authorityTest; import testRun.ChildOfAut; public class TheThirdClass { ChildOfAut a = new ChildOfAut(); AuthorityValidate b = new AuthorityValidate(); String c = b.authority2; String d = a.authority2; public static void main(String[] args) { AuthorityValidate b = new AuthorityValidate(); ChildOfAut a = new ChildOfAut(); System.out.print(b.authority2); System.out.print(a.authority2); } }
在testRun包中建立ChildOfAut类继承AuthorityValidate 并尝试调用AuthorityValidate 中不同权限的方法
package testRun; import authorityTest.AuthorityValidate; public class ChildOfAut extends AuthorityValidate { public static void main(String[] args) { ChildOfAut a = new ChildOfAut(); System.out.print(a.authority2); a.runProtectde("果然如此"); } }
在testRun包中建立TheOtherPackage类并尝试调用AuthorityValidate 中不同权限的方法
package testRun; import authorityTest.AuthorityValidate; public class TheOtherPackage { AuthorityValidate b = new AuthorityValidate(); String a = b.authority2; }
二、测试结果
TheThirdClass 类能调用AuthorityValidate 中protected修饰的属性和方法;
ChildOfAut类能调用AuthorityValidate 父类protected修饰的属性和方法;
TheOtherPackage类无法调用AuthorityValidate 父类protected修饰的属性和方法;
TheThirdClass,ChildOfAut,TheOtherPackage都不能访问AuthorityValidate 的private方法及属性;
以上,证明被protected修饰的属性、方法可被同一包中的类以及其子类访问。
被private修饰的属性、方法只能自身访问;
同理可证public可被任意类访问、default可被同一包中的类访问。