我定义了一个public类,提示公用类型必须在自己的文件中定义,请问是什么意思?

类名是否和文件名相同。

看看代码是怎样的？

public，要类名和文件名一样

我用eclipse新建一个类,名为OblongTester,下面是代码,我是自学菜鸟,大家帮看一下,谢谢
public class Oblong{
    private double length;
    private double height;
    public Oblong(double lengthIn, double heightIn)
    {
        length = lengthIn;
        height = heightIn;
        
    }
    public double getLength()
    {
        return length;
    }
    public double getHeight()
    {
        return height;
    }
    public void setLength(double lengthIn)
    {
        length = lengthIn;
    }
    public void setHeight(double heightIn)
    {
        height = heightIn;
    }
    public double calculateArea()
    {
        return length * height;
    }
    public double calculatePerimeter()
    {
        return 2 * (length + height);
        
    }
    
}
import java.util.*;

public class OblongTester{
    public  static void main(String[] args)
    {
        Scanner sc = new Scanner (System.in);
        double oblongLength, oblongHeight;
        Oblong myOblong;
        System.out.print("Please enter the length of your oblong:");
        oblongLength = sc.nextDouble();
        System.out.print("Please enter the height of your oblong:");
        oblongHeight = sc.nextDouble();
        myOblong = new Oblong(oblongLength, oblongHeight);
        System.out.println("Oblong length is " + myOblong.getLength());
        System.out.println("Oblong height is " + myOblong.getHeight());
        System.out.println("Oblong area is " + myOblong.calculateArea());
        System.out.println("Oblong perimeter is " + myOblong.calculatePerimeter());
    }
}

我把public class Oblong{放到用eclipse另一个新建的类文件里面就可以了,是不是说一个类文件只能放一个类呢,但我看到的课本有些代码是有几个类放在同一个类文件里面的,都可以执行.

可一个文件下只能有一个public的类啊

我试过只一个类是可以,而我想知道的是我上边的那代码里边有两个类,执行时提示Oblong类必须在他自己的文件中定义,请问是什么意思

我的意思就是让你看下这两个类是不是都是public的

恩,是的,都是public