Java类继承以及接口实现实例

Java类继承以及接口实现实例：这个实例非常容易理解，贴在这里与大家共享。

//抽象父类，交通工具(Vehicle)
public abstract class Vehicle{
  private  String name;
  private double cost;

  //无参构造函数    
  public Vehicle(){
  }

  //有参构造函数
  public Vehicle(String name, double cost){
    this.name = name;
    this.cost = cost;
  }

  //父类的抽象方法，在子类中要具体实现。    
  public abstract void run();    
  public abstract void stop();

  //getter方法    
  public String getName(){
    return this.name;
  }

  public double getCost(){
    return this.cost;
  }

  //setter方法
  public void  setName(String name){
    this.name = name;
  }

  public void setCost (double cost){
    this.cost = cost;
  }    
}



//上缴养路费的接口
public interface interRoadTax{
  public void tax();
}



//子类自行车Bike，继承Vehicle
public class Bike extends Vehicle{
  private int bikeType;

  //无参构造函数
  public Bike(){}
    
  //有参构造函数
  public Bike(String name, double cost, int type){
    super(name,cost); //通过父类方法进行赋值
    this.bikeType = type;
  }

  //setter方法    
  public void setBikeType(int type){
    this.bikeType = type;
  }
    
  //getter方法
  public int getBikeType(){
    return this.bikeType;
  }
    
  //继承父类Vehicle的抽象方法，在子类中要具体实现。
  public void run(){
    System.out.println("i am bike and running.....");
  }

  //继承父类Vehicle的抽象方法，在子类中要具体实现。    
  public void stop(){
    System.out.println("i am bike and stopping.....");
  }
}



//子类汽车Car，继承Vehicle，同时实现interRoadTax接口
public class Car extends Vehicle implements interRoadTax{
  private int numberOfPeople;
    
  //无参构造函数
  public Car(){}
    
  //有参构造函数
  public Car(String name, double cost, int numberOfPeople){
    super(name,cost);//通过父类方法进行赋值
    this.numberOfPeople = numberOfPeople;
  }
    
  //getter方法
  public int getNumberOfPeople(){
    return this.numberOfPeople;
  }
    
  public void setNumberOfPeople(int numberOfPeople){
    this.numberOfPeople = numberOfPeople;
  }
    
  //继承父类Vehicle的抽象方法，在子类中要具体实现。
  public void run(){
    System.out.println("i am car and running.....");
  }

  //继承父类Vehicle的抽象方法，在子类中要具体实现。
 public void stop(){
    System.out.println("i am car and stopping.....");
  }

  //实现上缴养路费的接口方法    
  public void tax(){
    System.out.println("the car tax is " + getCost() * 0.1);
  }    
}



//子类摩托车Motor，继承Vehicle，同时实现interRoadTax接口
public class Motor extends Vehicle implements interRoadTax{
  public Motor(){}
  public Motor(String name,double cost){
    super(name,cost);
  }
    
  public void run(){
    System.out.println("i am Motor and running.....");
  }
 
  public void stop(){
    System.out.println("i am Motor and stopping.....");
  }
    
  public void tax(){
    System.out.println("the motor tax is " + getCost() * 0.05);
  }    
}



//交通工具的主人
public class User{
  private int id;
  private String name;

  private Vehicle  v;
    
  public User(){}

  public User(int _id,String _name){
    id = _id;
    name = _name;
  }
    
  public void print(){
    System.out.println("the user is "+ id +" - "+ name);
  }
    
  public void setV(Vehicle v){
    this.v = v;
  }
    
  public Vehicle getV(){
    return this.v;
  }
}


//测试类
public class UserTest{
  public static void main(String[] args){
        
    User[] users = new User[3];

    Vehicle v1 = new Bike("fenghuang", 500.00, 1);
    Vehicle v2 = new Motor("honda", 10000.00);
    Vehicle v3 = new Car("polo", 145678.00, 5);
        
    users[0] = new User(1,"yanming");
    users[0].setV(v1);
    users[1] = new User(2,"laoxia");
    users[1].setV(v2);
    users[2] = new User(3,"zhaomengran");
    users[2].setV(v3);
        
    
    System.out.println("=====to begin test class=====");
    users[0].print();
    users[0].getV().run();
    users[1].print();
    users[1].getV().run();
    users[2].print();
    users[2].getV().run();
        
        
    System.out.println("=====to hand up Road Tax=====");
    for(User u : users){
      Vehicle v = u.getV();
      if(v instanceof Car){
        Car c = (Car)v;
        c.tax();
      }

      if(v instanceof Motor){
        Motor m = (Motor)v;
        m.tax();
      }

      if(v instanceof Bike){
        System.out.println(" hah ,no tax");
      }
    }
  }
}