Java，将JScrollPane添加到JPanel上的列表

我想知道是否有一种方法可以将JScrollPane添加到JList中，其中该列表位于JPanel上。我到处都找过这样的例子，但我找不到。滚动条不会出现

这是我的密码：

import java.awt.Dimension;
import javax.swing.*;
import javax.swing.ListSelectionModel;

public class MyClass{
public static void main(String args[]){

    //Declaring JFrame, JPanel, JList, JScrollPane objects
    JFrame frame = new JFrame();
    JPanel panel = new JPanel();
    JList list; 
    JScrollPane scroll; 
    String[] numberTest = {"1", "2", "3", "4", "5", "6", "7", "8", "9", "10"};

    //JFrame, frame
    frame.setResizable(false);
    frame.setLocationRelativeTo(null);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(500, 500);
    frame.setVisible(true);

    //JPanel, panel
    panel.setLayout(null);
    frame.add(panel);

    //JList, list
    list = new JList(numberTest);

    //list properties
    list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
    list.setLayoutOrientation(JList.VERTICAL);
    list.setVisibleRowCount(3);

    //Add JScrollPane to list   [What I need help with, its not working]
    JScrollPane listScroller = new JScrollPane(list);
    listScroller.setPreferredSize(new Dimension(250, 80));

    //Setbounds, add list and repaint frame
    list.setBounds(25, 25, 100, 100);
    panel.add(list);
    frame.repaint();

}
}

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将JScrollPane添加到JPanel

public class MyClass{
public static void main(String args[]){

//Declaring JFrame, JPanel, JList, JScrollPane objects
JFrame frame = new JFrame();
JPanel panel = new JPanel();
JList list; 
JScrollPane scroll; 
String[] numberTest = {"1", "2", "3", "4", "5", "6", "7", "8", "9", "10"};

//JFrame, frame
frame.setResizable(false);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(500, 500);
frame.setVisible(true);

//JPanel, panel
panel.setLayout(null);
frame.add(panel);

//JList, list
list = new JList(numberTest);

//list properties
list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
list.setLayoutOrientation(JList.VERTICAL);
list.setVisibleRowCount(3);

//Add JScrollPane to list   [What I need help with, its not working]
JScrollPane listScroller = new JScrollPane(list);
listScroller.setPreferredSize(new Dimension(250, 80));

//Setbounds, add list and repaint frame
listScroller.setBounds(25, 25, 100, 100);
panel.add(listScroller);
frame.repaint();
}
}

---

将

列表滚动条

添加到

面板

，而不是

列表

面板.setLayout（null）是问题之一