(1) The Song Class

Implement a class called Song that represents a song that is available
at the Music Exchange Center. The class should have these attributes:

• title - a String indicating the title of the song
• artist - a String indicating the artist(s) or band that recorded the song
• duration – an int indicating the number of seconds that the song lasts when played

Implement the following instance methods:

• A zero-parameter constructor.

• A constructor that accepts as parameters the song's title, artist, number of minutes and number of
seconds. (e.g., new Song("Angels Crying", "E-Type", 4, 35))

• A toString() method that returns a string representation of the song showing the title (within
double quotes), the artist and the duration (broken down in minutes and seconds).

For example: "Angels Crying" by E-Type 4:35

Test your code before continuing using this program:

class SongTestProgram {
      public static void main(String args[]) {
           Song song1, song2, song3;

           song1 = new Song();
           song2 = new Song("Hey Jude", "The Beatles", 4, 35);
           song3 = new Song("Barbie Girl", "Aqua", 3, 54);
           System.out.println(song1); // should display "" by 0:0
           System.out.println(song2); // should display "Hey Jude" by The Beatles 4:35
           System.out.println(song3); // should display "Barbie Girl" by Aqua 3:54
           System.out.println(song2.duration); // should display 275
           System.out.println(song3.duration); // should display 234
     }
}

public class Song {
    private String title ="";
    private String artist = "";
    private String duration ="";//我比较懒，就暂时定义成string用的时候截取转化一下好了
    public Song(String title,String artist,String duration){
        this.title = title;
        this.artist = artist;
        this.duration = duration;
    }
    public Song(){}
}
其实就这么简单，不要被外语搞蒙了。