java继承

package aa;public class Vehicle {    private int capacity;    public Vehicle() {        this.capacity = 2;        System.out.println("执行交通工具类的无参构造方法。");    }    public Vehicle(int capacity) {        this.capacity = capacity;        System.out.println("执行交通工具的有参构造方法。");    }    public int getCapacity() {        return capacity;    }    public void setCapacity(int capacity) {        this.capacity = capacity;    }    public void print(){        System.out.println("载客人数为："+this.capacity);    }}

package aa;public class Car extends Vehicle{    private int speed;    public int getSpeed() {        return speed;    }    public void setSpeed(int speed) {        this.speed = speed;    }    public Car(){        this.speed=0;        System.out.println("执行汽车类的无参构造方法。");    }    public Car(int speed){        super(22);        this.speed=speed;        System.out.println("执行汽车类的有参构造方法。");    }    public int speedup(int data){        for(;data>0;data--){        this.speed+=10;        }        return this.speed;    }    public int speeddown(int data){        for(;data>0;data--){        this.speed-=15;        }        return this.speed;    }    public void print (){        System.out.println("速度："+this.speed+"载客量："+getCapacity());    }}

package bb;

import aa.Car;
public final class Bus extends Car{
private int capacity;
public Bus(){
this.capacity=20;
System.out.println(“执行公交车类的无参构造方法。”);
}
public Bus(int capacity){
super(50);
this.capacity=capacity;
System.out.println(“执行公交车类的有参构造方法。”);
}
public void print(){
System.out.println(“速度：”+getSpeed()+”载客量”+capacity+”父类的载客量”+getCapacity());
}
}

package bb;

import aa.Car;

public class Text {

public static void main(String[] args) {    // TODO Auto-generated method stub    Car car=new Car();    car.speedup(5);    car.print();    car.speeddown(2);    car.print();    Bus bus=new Bus(20);    bus.print();}

}
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