维持功能的状态。范例：在子类之中扩充父类的功能classPerso
privateStri
g
ameprivatei
tagepublicvoidsetNameStri
g
amethis
ame
amepublicvoidsetAgei
tagethisageagepublicStri
ggetNameretur
this
amepublici
tgetAgeretur
thisageclassStude
texte
dsPerso
Stude
t类继承了Perso
类privateStri
gschool子类的属性publicvoidsetSchoolStri
gschoolthisschoolschoolpublicStri
ggetSchoolretur
thisschoolclassTestDemo5publicstaticvoidmai
Stri
gargsStude
tstu
ewStude
tStude
t类继承了Perso
类
fstusetName