java - 使用 Collections.sort() 对 MP3 列表进行排序

Question

我使用 Collections.sort() 按运行时间顺序对 MP3 列表进行排序，如果运行时间相等，则按标题按字母顺序排序，如果标题相等则按 Composer 。我将输入放入 stdin 即

输入示例

3
&
Pink Frost&Phillipps, Martin&234933
Se quel guerrier io fossi&Puccini, Giacomo&297539
Non piu andrai&Mozart&234933
M'appari tutt'amor&Flotow, F&252905

But then it doesn't come up with anything via the input. I am confused since it should work perfectly. I don't get any errors.

public class Lab3Algorithm {

public static void main(String args[]) throws IOException {

    List<Song> songs = new ArrayList<Song>();
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

    int numOfSongsRequired = Integer.parseInt(br.readLine());
    String sep = br.readLine();

    String line;
    while((line = br.readLine()) != null) {
        String[] fields = sep.split(line);
        songs.add(new Song(fields[0], fields[1], fields[2]));
    }
    Collections.sort(songs);

    System.out.println(songs);
}

}

public class Song implements Comparable<Song> {

private final String title;
private final String composer;
private final int runningTime;

public Song(String title, String composer, String runningTime) {
    this.title = title;
    this.composer = composer;
    this.runningTime = Integer.parseInt(runningTime);
}

public String getTitle(){
    return this.title;
}

public String getComposer(){
    return this.composer;
}

public int getRunningTime(){
    return this.runningTime;
}

@Override
public int compareTo(Song s) {
    if (runningTime > s.runningTime) {
        return 1;
    } else if (runningTime < s.runningTime) {
        return -1;
    }
    int lastCmp = title.compareTo(s.title);
    return (lastCmp != 0 ? lastCmp : composer.compareTo(s.composer));
}
}

如果有人能指出我正确的方向，我会感激不尽。

Answer 1

String[] fields = sep.split(line); 似乎是错误的 - 您没有尝试拆分歌曲输入上的分隔符字符串；您想要在分隔符上分割输入的歌曲:

String[] fields = line.split(sep);