我怎样才能改变这个使用超类的方法的输出

Question

嗨，我想知道如何更改显示方法的输出，以便输出，目前看起来是这样的：

Leonardo da Vinci
40 seconds ago - 2 people like this.
No comments.
Had a great idea this morning.
But now I forgot what it was. Something to do with flying...

可以做成这样

Leonardo da Vinci
Had a great idea this morning.
But now I forgot what it was. Something to do with flying...
40 seconds ago - 2 people like this.
No comments.

就是这两个方法，负责超类中的部分输出

public String toString()
{

    String text = username + "\n" + timeString(timestamp);

    if(likes > 0) {
        text+= "  -  " + likes + " people like this.\n";
    }
    else {
        text+= "\n";
    }

    if(comments.isEmpty()) {
        return text + "   No comments.\n";
    }
    else {
        return text + "   " + comments.size() + 
        " comment(s). Click here to view.\n";
    }
}

public void display()
{
    System.out.println(toString());
}

这是子类中的两个方法，通过调用上面的父类完成输出

   public String toString()
    {
        return super.toString() + message + "\n";
    }

    /**
     * Display the details of this post.
     * 
     * (Currently: Print to the text terminal. This is simulating display 
     * in a web browser for now.)
     */
    public void display()
    {
        System.out.println(toString());
    }

Answer 1

这是您期望的结果：

Leonardo da Vinci
Had a great idea this morning.
But now I forgot what it was. Something to do with flying...

40 seconds ago - 2 people like this.
No comments.

message的值为：

Had a great idea this morning.
But now I forgot what it was. Something to do with flying...

而 super.toString() 的值：

40 seconds ago - 2 people like this.
No comments.

你的子类 toString() returns 这个：

public String toString()
{
    return super.toString() + message + "\n";
}

你的结果是：super.toString():

Leonardo da Vinci
40 seconds ago - 2 people like this.
No comments.

和message:

 Had a great idea this morning.
 But now I forgot what it was. Something to do with flying...

你明白为什么要按这个顺序打印了吗？您只需将顺序更改为：

return message + super.toString() + "\n";

这将更改它的显示顺序。

并在变量 message

中打印 super.toString() 中的 username 的值

Answer 2

您可以为类中的每个字符串创建单独的方法，并在构建您的最终字符串时单独调用它们。

例如：

在超类中：

public String getUsername() {
    return username;
}

public String getTimeString() {
    return timeString(timestamp);
}

在子类中：

public void display() {
    System.out.println(super.getTimeString()+"\n"+message);
    //or put whatever in whatever order you want.
}

我怎样才能改变这个使用超类的方法的输出

how can I change the output of this method which uses a superclass

java

inheritance

subclass

superclass

bluej