使用java设计一个MyMedia类，其中包含MyBook、MyCd及MyTape三个子类。按照类的设计模式，完成他们的插入、删除、及查找功能。并且还拥有一个interfaceMedias接口和一个MediaTest测试类,interfaceMedias接口的方法有public int addMedia(Vector medias,MyMedia tempMedia); public int deleteMedia(Vector medias); public MyMedia findMedia(Vector medias,String artist); public void printlnMedia(Vector medias); public String input(); 并且MediaTest测试类实现了interfaceMedias接口

好的，我理解了你的问题。以下是Java代码实现：

首先是MyMedia类，包含MyBook、MyCd及MyTape三个子类：

public class MyMedia {
    private String title;
    private String artist;
    private int year;

    public MyMedia(String title, String artist, int year) {
        this.title = title;
        this.artist = artist;
        this.year = year;
    }

    public String getTitle() {
        return title;
    }

    public String getArtist() {
        return artist;
    }

    public int getYear() {
        return year;
    }

    @Override
    public String toString() {
        return "MyMedia{" +
                "title='" + title + '\'' +
                ", artist='" + artist + '\'' +
                ", year=" + year +
                '}';
    }
}

class MyBook extends MyMedia {
    private String author;
    private String publisher;

    public MyBook(String title, String artist, int year, String author, String publisher) {
        super(title, artist, year);
        this.author = author;
        this.publisher = publisher;
    }

    public String getAuthor() {
        return author;
    }

    public String getPublisher() {
        return publisher;
    }

    @Override
    public String toString() {
        return "MyBook{" +
                "title='" + getTitle() + '\'' +
                ", artist='" + getArtist() + '\'' +
                ", year=" + getYear() +
                ", author='" + author + '\'' +
                ", publisher='" + publisher + '\'' +
                '}';
    }
}

class MyCd extends MyMedia {
    private String label;

    public MyCd(String title, String artist, int year, String label) {
        super(title, artist, year);
        this.label = label;
    }

    public String getLabel() {
        return label;
    }

    @Override
    public String toString() {
        return "MyCd{" +
                "title='" + getTitle() + '\'' +
                ", artist='" + getArtist() + '\'' +
                ", year=" + getYear() +
                ", label='" + label + '\'' +
                '}';
    }
}

class MyTape extends MyMedia {
    private String genre;
    private String length;

    public MyTape(String title, String artist, int year, String genre, String length) {
        super(title, artist, year);
        this.genre = genre;
        this.length = length;
    }

    public String getGenre() {
        return genre;
    }

    public String getLength() {
        return length;
    }

    @Override
    public String toString() {
        return "MyTape{" +
                "title='" + getTitle() + '\'' +
                ", artist='" + getArtist() + '\'' +
                ", year=" + getYear() +
                ", genre='" + genre + '\'' +
                ", length='" + length + '\'' +
                '}';
    }
}

接下来是interfaceMedias接口：

import java.util.Vector;

public interface interfaceMedias {
    public int addMedia(Vector medias, MyMedia tempMedia);
    public int deleteMedia(Vector medias);
    public MyMedia findMedia(Vector medias, String artist);
    public void printlnMedia(Vector medias);
    public String input();
}

然后是MediaTest测试类，实现了interfaceMedias接口：

import java.util.Scanner;
import java.util.Vector;

public class MediaTest implements interfaceMedias {
    public static void main(String[] args) {
        Vector<MyMedia> medias = new Vector<MyMedia>();
        MediaTest mediaTest = new MediaTest();

        MyBook myBook1 = new MyBook("Java Programming", "John Smith", 2004, "Jane Doe", "Wiley");
        MyBook myBook2 = new MyBook("Python Programming", "Alice Brown", 2018, "Bob Green", "O'Reilly");
        MyCd myCd1 = new MyCd("Greatest Hits", "The Beatles", 2000, "EMI");
        MyCd myCd2 = new MyCd("Thriller", "Michael Jackson", 1982, "Epic");
        MyTape myTape1 = new MyTape("The Wall", "Pink Floyd", 1979, "Rock", "81:09");
        MyTape myTape2 = new MyTape("Purple Rain", "Prince", 1984, "Pop", "43:49");

        mediaTest.addMedia(medias, myBook1);
        mediaTest.addMedia(medias, myCd1);
        mediaTest.addMedia(medias, myTape1);
        mediaTest.addMedia(medias, myBook2);
        mediaTest.addMedia(medias, myCd2);
        mediaTest.addMedia(medias, myTape2);

        mediaTest.printlnMedia(medias);

        mediaTest.deleteMedia(medias);

        mediaTest.printlnMedia(medias);

        MyMedia result = mediaTest.findMedia(medias, "The Beatles");
        if (result != null) {
            System.out.println("Found media: " + result);
        } else {
            System.out.println("Media not found");
        }
    }

    public int addMedia(Vector medias, MyMedia tempMedia) {
        medias.add(tempMedia);
        return medias.size();
    }

    public int deleteMedia(Vector medias) {
        Scanner scanner = new Scanner(System.in);
        System.out.println("Enter the artist name to delete: ");
        String artist = scanner.nextLine();
        for (int i = 0; i < medias.size(); i++) {
            MyMedia media = (MyMedia) medias.elementAt(i);
            if (media.getArtist().equals(artist)) {
                medias.removeElementAt(i);
            }
        }
        return medias.size();
    }

    public MyMedia findMedia(Vector medias, String artist) {
        for (int i = 0; i < medias.size(); i++) {
            MyMedia media = (MyMedia) medias.elementAt(i);
            if (media.getArtist().equals(artist)) {
                return media;
            }
        }
        return null;
    }

    public void printlnMedia(Vector medias) {
        System.out.println("Media List:");
        for (int i = 0; i < medias.size(); i++) {
            MyMedia media = (MyMedia) medias.elementAt(i);
            System.out.println(media);
        }
    }

    public String input() {
        Scanner scanner = new Scanner(System.in);
        System.out.println("Enter input:");
        String input = scanner.nextLine();
        return input;
    }
}

MediaTest测试类中包含了六个媒体对象，分别是两本书、两张CD和两盘磁带。在main()方法中，我们首先创建了一个MyMedia对象的向量medias，然后创建了MediaTest对象mediaTest，并将六个媒体对象添加到medias中。接着，我们调用了mediaTest的printlnMedia()方法，打印出medias中所有媒体对象的信息。

接下来，我们调用了mediaTest的deleteMedia()方法，删除了一个指定艺术家的媒体对象，并再次调用了printlnMedia()方法，打印出更新后的medias中所有媒体对象的信息。

最后，我们调用了mediaTest的findMedia()方法，查找指定艺术家的媒体对象，并打印出查找结果。

希望这份代码能够对你有帮助！