java之day8多態

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多態

package day8;public abstract class Instrument {    public abstract void play();}

package day8;public class Piano extends Instrument{    @Override    public void play() {        // TODO Auto-generated method stub        System.out.println("yueguangqu");    }}

package day8;public class Violin extends Instrument{        public void play() {        // TODO Auto-generated method stub        System.out.println("風吹麥浪");    }}

package day8;//多態類題型：//使用繼承//子類重寫父類的方法//父類引用子類對象public class Artist {//    public void make(Piano piano){//        piano.play();//    }//    public void make(Violin violin){//        violin.play();//    }        public void make(Instrument instrument){        instrument.play();    }}

package day8;public class Test {    public static void main(String[] args) {        Artist artist = new Artist();        Piano piano = new Piano();        artist.make(piano);        Violin violin = new Violin();        artist.make(violin);    }}

 

 

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介面

package day83;public interface InterfaceDemo {    //1:介面不能被執行個體化    //2：介面裡的方法預設都是public類型的抽象方法    //所有public abstract修飾可以忽略    //3:類是單繼承，但是類可以實現多個介面    //4:在介面裡定義的屬性都是public類型的靜態常量    //public static final都是可以省略的    //5:介面可以繼承多個介面，可以得到父級介面裡所有的屬性和方法        public abstract void showName();        public static final int AGE = 10;}

package day83;public interface InterfaceDemo2 {    void showName2(); }

package day83;public abstract class Father {    public abstract void showFatherName();}

package day83;public abstract class Father2 {    public abstract void showFatherName2();}

package day83;public interface ChildInterface extends InterfaceDemo,InterfaceDemo2{}

package day83;import java.nio.channels.ShutdownChannelGroupException;public class Test extends Father implements InterfaceDemo,InterfaceDemo2{    public static void main(String[] args) {//        Interface demo = new InterfaceDemo();是不可以的        Test test = new Test();            }    @Override    public void showName() {        // TODO Auto-generated method stub            }    @Override    public void showName2() {        // TODO Auto-generated method stub            }    @Override    public void showFatherName() {        // TODO Auto-generated method stub            }}

 

 

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綜合類

package day86;public class A4Paper implements Paper{    @Override    public void pageSize() {        System.out.println("使用A4紙！");    }}

package day86;public class B5Paper implements Paper{    @Override    public void pageSize() {        System.out.println("使用B5紙！");    }}

package day86;public class BlackInk implements Ink{    @Override    public void inkColor() {        System.out.println("使用黑白墨！");    }}

package day86;public class ColorInk implements Ink{    @Override    public void inkColor() {        System.out.println("使用彩墨！");    }}

package day86;public interface Ink {    void inkColor();}

package day86;public interface Paper {    void pageSize();}

package day86;public class Printer {    public Ink ink;    public Paper paper;    public void print(String content){        ink.inkColor();        paper.pageSize();        System.out.println(content);    }    public static void main(String[] args) {        Printer printer = new Printer();        printer.ink = new BlackInk();        printer.paper = new A4Paper();        printer.print("我是列印內容！");            }    }

 

java之day8多態