Java文件I / O有問題嗎？

Question

我在I / O方面遇到麻煩。 我有一個名為SongTextFileProcessor的類，該類應該處理從文件讀取/寫入Song對象（在Song類中定義）的操作。 這是我的寫方法：

@Override
public void writeSong(String songName, String fileName) 
{
    String [] songObject = songName.split(", ");
    Song s1 = new Song (songObject[0], songObject[1], songObject[2]);

    try
    {
    PrintWriter output = new PrintWriter (new File (fileName));
    output.print(s1.printSong());
    output.close();
    }
    catch (Exception e)
    {
        System.out.println("Exception caught.");
    }
}

和我的閱讀方法：

@Override
public void readSong(String fileName) 
{
    try
    {
    BufferedReader in = new BufferedReader(new FileReader(fileName));

    String line = null;
    while((line = in.readLine()) != null)   
    {
        System.out.println(line);
    }
    in.close();
    }

    catch (Exception e)
    {
        System.out.println("Exception caught.");
    }
}

但是，當我嘗試使用以下代碼從Test類調用這些方法時：

String songName = "Maad City, Kendrick Lamar, Hip-Hop";
String fileName = "songs.txt";

writeSong(songName, fileName);
readSong(fileName);

它給我一個錯誤：“類型Test的方法writeSong（String，String）未定義”。 這讓我感到沮喪，因為我熟悉Java I / O和一般的Java，並且當從Test類調用這兩種方法時，它們都能正常工作，這意味着問題一定在將參數傳遞給SongTextFileProcessor中的方法。 有任何想法嗎？

這是歌曲課程：

public class Song 
{
private String title, artist, genre;

public String getTitle()
{
    return title;
}

public void setTitle(String title) 
{
    this.title = title;
}

public String getArtist() 
{
    return artist;
}

public void setArtist(String artist) 
{
    this.artist = artist;
}

public String getGenre() 
{
    return genre;
}

public void setGenre(String genre) 
{
    this.genre = genre;
}

public Song(String title, String artist, String genre)
{
    this.title = title;
    this.artist = artist;
    this.genre = genre;
}

public String printSong()
{
    return (getTitle() + " by " + getArtist() + " is a " + getGenre() + " song.");
}
}

The readSong and writeSong methods are the only methods in the SongTextFileProcessor class, and both of those methods are defined by Interfaces. And i've shown all the code I have in the Test class. 

Answer 1

在文本類中嘗試一下：

    String songName = "Maad City, Kendrick Lamar, Hip-Hop";
    String fileName = "songs.txt";

    SongTextFileProcessor stfp = new SongTextFileProcessor ();

    stfp.writeSong(songName, fileName);
    stfp.readSong(fileName);