方法可以重寫,變量可以嗎
測試類:
public?class?Initail?{ ????public?static?void?main(String[]?args)?{ ????????Phone?phone?=?new?Phone(); ????????SmartPhone?smartPhone?=?new?SmartPhone(); ????????phone.call(); ????????smartPhone.call(); ????????phone.printTarget(); ????????smartPhone.printTarget(); ????} }
父類
public?class?Phone?{ ????String?target?=?"me"; ????public?void?call(){ ????????System.out.println("You?call?to?"+this.target); ????} ????public?void?printTarget(){ ????????System.out.println(this.target); ????} }
子類
public?class?SmartPhone?extends?Phone?{ ????//String?target?=?"notme"; ????//不寫這一行,this.target?為父類中的me ????public?void?call(){ ????????System.out.println("You?call?to?"+this.target); ????} ????public?void?printTarget(){ ????????System.out.println(this.target); ????} }
此時運行smartPhone.printTarget()的結果為me,在該類里沒有target變量,它卻識別到了父類里的target,但如果去掉注釋,他就會使用子類的target,這算是一種重寫嗎?按理說不可以定義重名的變量,那么是重寫了(子類有target變量,被覆寫為notme),還是說目前的子類中沒有target變量,變量是父類的呢?(類似于子類沒有target存在時,target 就相當于是 super.target)
2021-01-04
是一種重寫
2020-09-14
變量不可以重寫