java 三大特性之继承

public class  {
    public static void main(String[] str) {
        Son simple = new Son();
        simple.method();
        simple.printStr();
        simple.method("simple");
    }
}
class Father {
    
    public String str = "Simple";
    Father() {
        System.out.println("This is the Father's " + str);
    }
    //父类的非private方法，子类可以调用
    public void method() {
        System.out.println("This is the Father's method");
    }
    public void method(String strs) {
        System.out.println("This is the Father's method with param");
    }
}
class Son extends Father {
    //子类可以拥有自己的属性
    private String ownStr = "ownStr";
    Son() {
        super();
        System.out.println("This is the Son's " +
                          super.str);
    }
    //子类可以拥有自己的方法
    public void printStr() {
        System.out.println("This is the " +
                          "Son's method");
    }
    //子类可以重写父类的方法
    public void method(String strs) {
        System.out.println("This is the Son's method, " +
                          "which is overriding from Father");
    }
}

public class  {
    public static void main(String[] str) {
        new GouZaoQiTwo();
        new GouZaoQiFour("simple");
    }
}
class GouZaoQiOne {
    GouZaoQiOne() {
        System.out.println("This is GouZaoQiOne");
    }
}
class GouZaoQiTwo extends GouZaoQiOne{
    //子类会默认调用父类的无参数构造器
}
class GouZaoQiThree {
    GouZaoQiThree(String str) {
        System.out.println("This is the gouzaoqi with param.");
    }
}
class GouZaoQiFour extends GouZaoQiThree{
    GouZaoQiFour(String str){
        //如果父类没有无参构造器，子类必须要显式的指定父类的构造器(有参数)，
        //而且必须是在子类构造器第一行进行调用
        super(str);
        System.out.println("This is GouZaoQiFour");
    }
}

public class  {
    public static void main(String[] str) {
        GouZaoQiTwo gouZaoQiTwo = new GouZaoQiTwo();
        //method方法的参数实际要求的类型是GouZaoQiOne，
        //但是因为GouZaoQiTwo是GouZaoQiOne的子类，
        //所以可以通过向上转型来满足参数类型的需要
        gouZaoQiTwo.method(gouZaoQiTwo);
    }
}
class GouZaoQiOne {
    public void method(GouZaoQiOne gouZaoQiOne) {
        System.out.println("This is GouZaoQiOne");
    }
}
class GouZaoQiTwo extends GouZaoQiOne{
}

public class  {
    public static void main(String[] str) {
        ZiXingChe ziXingChe = new ZiXingChe("sylan215");
        DianDongChe dianDongChe = new DianDongChe("sylan215-1");
        ziXingChe.run();
        ziXingChe.sleep();
        ziXingChe.reboot();
        dianDongChe.run();
        dianDongChe.sleep();
        dianDongChe.power();
    }
}
class ZiXingChe {
    private String name;
    ZiXingChe(String name) {
        this.name = name;
        System.out.println("This is a " + name);
    }
    public void run() {
        System.out.println("I am a " + this.name + ", I can run");
    }
    public void sleep() {
        System.out.println("I am a " + this.name + ", I need sleep");
    }
    public void reboot() {
        System.out.println("I am a " + this.name + ", I need reboot");
    }
}
class DianDongChe {
    private String name;
    DianDongChe(String name) {
        this.name = name;
        System.out.println("This is a " + name);
    }
    public void run() {
        System.out.println("I am a " + this.name + ", I can run");
    }
    public void sleep() {
        System.out.println("I am a " + this.name + ", I need sleep");
    }
    public void power() {
        System.out.println("I am a " + this.name + ", I need power");
    }
}

public class  {
    public static void main(String[] str) {
        ZiXingChe ziXingChe = new ZiXingChe("sylan215");
        DianDongChe dianDongChe = new DianDongChe("sylan215-1");
        ziXingChe.run();
        ziXingChe.sleep();
        ziXingChe.reboot();
        dianDongChe.run();
        dianDongChe.sleep();
        dianDongChe.power();
    }
}
class CheZi {
    private String name;
    CheZi(String name) {
        this.name = name;
        System.out.println("This is a " + name);
    }
    public void run() {
        System.out.println("I am a " + this.name + ", I can run");
    }
    public void sleep() {
        System.out.println("I am a " + this.name + ", I need sleep");
    }
}
class ZiXingChe extends CheZi {
    private String name;
    ZiXingChe(String name) {
        super(name);
        this.name = name;
    }
    public void reboot() {
        System.out.println("I am a " + this.name + ", I need reboot");
    }
}
class DianDongChe extends CheZi {
    private String name;
    DianDongChe(String name) {
        super(name);
        this.name = name;
    }
    public void power() {
        System.out.println("I am a " + this.name + ", I need power");
    }
}