toString方法

Question

我想toString在Item类中添加一个返回项目标题的方法.

我需要确保类中的toString方法DVD调用该toString方法,Item以便它可以返回包含title和director的字符串.

Item是超类,DVD是子类.

  public class Item
   {
  private String title;
  private int playingTime;
  private boolean gotIt;
  private String comment;

public Item(String theTitle, int time)
{
    title = theTitle;
    playingTime = time;
    gotIt = false;
    comment = "<no comment>";
}

// Getters and setters omitted

public void print()
{
    System.out.print(title + " (" + playingTime + " mins)");
    if(gotIt) {
        System.out.println("*");
    } else {
        System.out.println();
    }
    System.out.println("    " + comment);
}

}

 public class DVD extends Item 
 {
 private String director;

public DVD(String theTitle, String theDirector, int time)
{
    super(theTitle, time);
    director = theDirector;
}

// Getters and setters omitted

public void print()
{
    System.out.println("    director: " + director);
}

}

Answer 1

项目toString:

public String toString()
{
  return title;
}

DVD toString:

public String toString()
{
  return super.toString() + " director: " + director;
}

另外,我不知道你要做什么,但我会把这些print()方法放在这些类中.

您将更好地返回字符串表示并将其打印到其他位置(使用此功能,您可以在不进行模拟的情况下测试此类System.out)

干杯