【Thinking in Java笔记】怎么使用protected关键字

尽管可以创建protected域，但是最好的方式还是将域保持为private；

你应当一直保留“更改底层实现”的权利。

然后通过protected方法来控制类的继承者的访问权限：

class Villain {private String name;protected void set(String name) {this.name = name;}public Villain(String name) {this.name = name;}public String toString() {return "I'm Villain and my name is " + name;}}public class Orc extends Villain {private int orcNumber;public Orc(String name, int orcNumber) {super (name);this.orcNumber = orcNumber;}public void change(String name, int orcNumber) {set(name);this.orcNumber = orcNumber;}public String toString() {return "Orc " + orcNumber + ": " + super.toString();}public static void main(String args[]) {Orc orc = new Orc("Limburger", 12);System.out.println(orc);orc.change("Bob", 19);System.out.println(orc);}}