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in Technique[技术] by (71.8m points)

请问下,这里为何会引发空指针异常?

图片描述

有人跟我讲,将name进行静态赋值即可,但实例变量不也是属于成员变量吗,也是在整个类实例化的时候产生的啊,跟静态赋值有何区别吗?


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父类的构造方法先于子类构造方法执行,Base()->test()-->name.length()相当于null.length()
name写成静态的话,当然可以了,因为静态成员的初始化先于实例成员的初始化。

顺序大概是这样的:

  • 父类static{...}

  • 父类静态成员

  • 父类构造方法

  • 子类static{...}

  • 子类静态成员

  • 子类构造方法


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