主方法代码：

package com.aynu.layout;

import com.aynu.model.NumberComboBoxListModel;
import com.aynu.model.NumberListModel;

import javax.swing.*;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
import java.awt.BorderLayout;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.math.BigDecimal;
import java.util.List;

public class ListModelTest {
    JFrame jf = new JFrame("测试ListModel");

    JList<BigDecimal> jList = new JList<>(new NumberListModel(new BigDecimal(1),new BigDecimal(21),new BigDecimal(2)));

    JComboBox<BigDecimal> jComboBox = new JComboBox<>(new NumberComboBoxListModel(new BigDecimal(0.1),new BigDecimal(1.2),new BigDecimal(0.1)));

    JLabel label = new JLabel("您选择的值是：");

    JTextField jTextField = new JTextField(15);

    public void init(){

        //组装视图

        //组装顶部
        jList.setVisibleRowCount(4);
        jList.setSelectionInterval(2,4);

        jList.setFixedCellWidth(90);
        jList.setFixedCellHeight(30);

        //注册监听器
        jList.addListSelectionListener(new ListSelectionListener() {
            @Override
            public void valueChanged(ListSelectionEvent e) {
                List<BigDecimal> selectedValuesList = jList.getSelectedValuesList();
                jTextField.setText("");
                for (BigDecimal item : selectedValuesList){
                    jTextField.setText(jTextField.getText()+item.toString()+",");
                }
            }
        });

        jComboBox.setMaximumRowCount(4);
        jComboBox.addItemListener(new ItemListener() {
            @Override
            public void itemStateChanged(ItemEvent e) {
                Object selectedItem = jComboBox.getSelectedItem();
                jTextField.setText(selectedItem.toString());
            }
        });

        Box hBox = Box.createHorizontalBox();
        hBox.add(new JScrollPane(jList));

        JPanel tempPanel = new JPanel();
        tempPanel.add(jComboBox);
        hBox.add(tempPanel);
        jf.add(hBox);


        //组装底部
        JPanel bottomPanel = new JPanel();
        bottomPanel.add(label);
        bottomPanel.add(jTextField);

        jf.add(bottomPanel, BorderLayout.SOUTH);


        jf.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        jf.pack();
        jf.setVisible(true);
    }

    public static void main(String[] args) {
        new ListModelTest().init();
    }
    }

package com.aynu.model;

import javax.swing.*;
import java.math.BigDecimal;
import java.math.RoundingMode;

public class NumberListModel extends AbstractListModel<BigDecimal> {
    BigDecimal start;
    BigDecimal end;
    BigDecimal step;

    public NumberListModel(BigDecimal start, BigDecimal end, BigDecimal step) {
        this.start = start;
        this.end = end;
        this.step = step;
    }


    @Override
    public int getSize() {
        int floor = (int) Math.floor(end.subtract(start).divide(step, 2, RoundingMode.HALF_DOWN).doubleValue());
        return floor + 1;
    }

    @Override
    public BigDecimal getElementAt(int index) {
        BigDecimal ele = new BigDecimal(index).multiply(step).add(start).setScale(2, RoundingMode.HALF_DOWN);

        return ele;
    }
}

 

package com.aynu.model;

import javax.swing.*;
import java.math.BigDecimal;
import java.math.RoundingMode;

public class NumberComboBoxListModel extends NumberListModel implements ComboBoxModel<BigDecimal> {

    //当前选中条目的索引
    private int selectedId;

    public NumberComboBoxListModel(BigDecimal start, BigDecimal end, BigDecimal step) {
        super(start, end, step);
    }

    @Override
    public void setSelectedItem(Object anItem) {

        if (anItem instanceof BigDecimal) {
            BigDecimal curr = (BigDecimal) anItem;
            selectedId = curr.subtract(super.start).divide(super.step, 2, RoundingMode.HALF_DOWN).intValue();
        }
    }

    @Override
    public Object getSelectedItem() {

        BigDecimal item = new BigDecimal(selectedId).multiply(super.step).add(super.start).setScale(1, RoundingMode.HALF_DOWN);

        return item;
    }
}