JList和JComboBox下拉选项框，列表选项框

package com.main;

import javax.swing.*;
import javax.swing.border.EtchedBorder;
import javax.swing.border.TitledBorder;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.util.List;
import java.util.Vector;

public class JToolBarDemo {
    public static void main(String[] age){
        new JToolBarDemo().init();
    }
    JFrame list_test = new JFrame("List Test");



    ButtonGroup layoutGroup = new ButtonGroup();

    JPanel selectModePanel = new JPanel();
    ButtonGroup selectGroup = new ButtonGroup();

    JTextArea favorite = new JTextArea(4, 40);

    JList<String> bookList;
    JComboBox<String> bookSelector;
    JPanel layoutPanel = new JPanel();

    public void init(){
        String[] books={"java自学宝典","轻量级JavaEE企业应用实战","Android基础教程","JQuery实战教程","SpringBoot企业级开发"};



        //组装试图

        //组装JList相关内容
        bookList=new JList<String>(books);
        addBtn2LayoutPanel("纵向滚动",JList.VERTICAL);
        addBtn2LayoutPanel("纵向换行",JList.VERTICAL_WRAP);
        addBtn2LayoutPanel("纵向换行",JList.HORIZONTAL_WRAP);

        addSelectModelPanel("无限制",ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
        addSelectModelPanel("单选",ListSelectionModel.SINGLE_SELECTION);
        addSelectModelPanel("单范围",ListSelectionModel.SINGLE_INTERVAL_SELECTION);

        //对Jlist做设置
        bookList.setVisibleRowCount(3);
        bookList.setSelectionInterval(2,4);//第3个到第五个默认选中
        //处理list选中事件
        bookList.addListSelectionListener(new ListSelectionListener() {
            @Override
            public void valueChanged(ListSelectionEvent e) {
                //获取当前选中的条目
                List<String> selectedValuesList = bookList.getSelectedValuesList();
                favorite.setText("");
                //把当前选中的内容设置到文本域中
                for (String str:selectedValuesList){
                    favorite.append(str);
                }
            }
        });
        Box bookListVBox = Box.createVerticalBox();
        bookListVBox.add(new JScrollPane(bookList));
        bookListVBox.add(layoutPanel);
        bookListVBox.add(selectModePanel);

        //组装JComboBox
        Vector<String> vector=new Vector<>();
        List<String> list = List.of("java自学宝典", "轻量级JavaEE企业应用实战", "Android基础教程", "JQuery实战教程", "SpringBoot企业级开发");
        vector.addAll(list);
        bookSelector=new JComboBox<>(vector);
        bookSelector.setEditable(true);
        bookSelector.setMaximumRowCount(4);
        bookSelector.addItemListener(new ItemListener() {
            @Override
            public void itemStateChanged(ItemEvent e) {

                //获取当前已经选中的条目，把内容设置到文本域
                Object selectedItem = bookSelector.getSelectedItem();
                favorite.setText(selectedItem.toString());

            }
        });

    //顶部部分组装
        Box horizontalBox = Box.createHorizontalBox();
        horizontalBox.add(bookListVBox);
        JPanel jPanel1 = new JPanel();
        jPanel1.add(bookSelector);
        horizontalBox.add(jPanel1);
//        horizontalBox.add(bookSelector);//直接放进去结果会导致下拉框被拉伸，对此需要加一个JLabel进行过滤

//组装底部
        JPanel jPanel = new JPanel();
        jPanel.setLayout(new BorderLayout());
        jPanel.add(new JLabel("您喜欢的图书："),BorderLayout.NORTH);
        jPanel.add(favorite);

        //组装整体布局
        Box holeBox = Box.createVerticalBox();
        holeBox.add(horizontalBox);
        holeBox.add(jPanel);
        list_test.add(holeBox);
        list_test.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        list_test.pack();
        list_test.setVisible(true);
    }
    //封装方法，往layoutPanel中添加单选按钮
    public void addBtn2LayoutPanel(String name,int layoutType){
        //设置标题边框
        layoutPanel.setBorder(new TitledBorder(new EtchedBorder(),"确定选项布局"));

        //创建单选按钮
        JRadioButton jRadioButton = new JRadioButton(name);
        layoutPanel.add(jRadioButton);
        //让第一个按钮默认选中
        if(layoutGroup.getButtonCount()==0){
            jRadioButton.setSelected(true);
        }
        layoutGroup.add(jRadioButton);

        jRadioButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                bookList.setLayoutOrientation(layoutType);
            }
        });
    }
    //封装方法，往SelectModelPanel中添加单选按钮
    public void addSelectModelPanel(String name,int ModelPanel){
        //设置标题边框
        selectModePanel.setBorder(new TitledBorder(new EtchedBorder(),"选择模式"));

        //创建单选按钮
        JRadioButton jRadioButton = new JRadioButton(name);
        selectModePanel.add(jRadioButton);//添加一个组是否可以？

        //让第一个按钮默认选中
        if(selectGroup.getButtonCount()==0){
            jRadioButton.setSelected(true);
        }
        selectGroup.add(jRadioButton);

        jRadioButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
              bookList.setSelectionMode(ModelPanel);
            }
        });
    }
}

当出现个性化需求时可以重写AbstractListModel进行个性化开发

package test.object.model;

import java.awt.BorderLayout;
import java.awt.event.ItemEvent;
import java.awt.event.ItemListener;
import java.math.BigDecimal;
import java.util.List;

import javax.swing.Box;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JList;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTextField;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;

public class ListModelTest {
    public void init() {
        JFrame jf = new JFrame("test");

        JList<BigDecimal> jList = new JList<>(
                new NumberListModel(new BigDecimal(1), new BigDecimal(5), new BigDecimal(2)));

        JComboBox<BigDecimal> jComboBox = new JComboBox<BigDecimal>(
                new NumberComboBoxList(new BigDecimal(0.1), new BigDecimal(0.5), new BigDecimal(0.2)));
        JLabel jLabel = new JLabel("您选择的直是：");
        JTextField jTextField = new JTextField(15);

        // 组装试图

        // 组装顶部
        jList.setVisibleRowCount(4);
        jList.setSelectionInterval(2, 3);

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

        jList.addListSelectionListener(new ListSelectionListener() {

            @Override
            public void valueChanged(ListSelectionEvent e) {
                // TODO Auto-generated method stub
                List<BigDecimal> selectedValue = jList.getSelectedValuesList();
                jTextField.setText("");
                for (BigDecimal data : selectedValue) {
                    jTextField.setText(jTextField.getText() + data.toString() + ",");
                }
            }
        });

        jComboBox.setMaximumRowCount(4);// 可视高度
        jComboBox.addItemListener(new ItemListener() {

            @Override
            public void itemStateChanged(ItemEvent e) {
                // TODO Auto-generated method stub
                Object selectedItem = jComboBox.getSelectedItem();
                jTextField.setText(selectedItem.toString());
            }
        });

        Box createHorizontalBox = Box.createHorizontalBox();
        createHorizontalBox.add(new JScrollPane(jList));
        JPanel jPanel = new JPanel();
        jPanel.add(jComboBox);
        createHorizontalBox.add(jPanel);
        jf.add(createHorizontalBox);
        // 组装底部
        JPanel jPanel2 = new JPanel();
        jPanel2.add(jLabel);
        jPanel2.add(jTextField);

        jf.add(jPanel2, BorderLayout.SOUTH);

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

    }

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

NumberListModel

package test.object.model;

import java.math.BigDecimal;
import java.math.RoundingMode;

import javax.swing.AbstractListModel;

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() {
        // 计算一共多少个项
        int doubleValue = (int) Math.floor(end.subtract(start).divide(step, 2, RoundingMode.HALF_DOWN).doubleValue());
        return doubleValue + 1;
    }

    @Override
    public BigDecimal getElementAt(int index) {
        // 根据指定的索引获取条目
        BigDecimal setScale = new BigDecimal(index).multiply(step).add(start).setScale(2, RoundingMode.HALF_DOWN);
        return setScale;
    }

}

NumberComboBoxList列表项目

package test.object.model;

import java.math.BigDecimal;
import java.math.RoundingMode;

import javax.swing.ComboBoxModel;

public class NumberComboBoxList extends NumberListModel implements ComboBoxModel<BigDecimal> {
    private int seletedID;

    public NumberComboBoxList(BigDecimal start, BigDecimal end, BigDecimal step) {
        super(start, end, step);
        // TODO Auto-generated constructor stub
    }

    @Override
    public void setSelectedItem(Object anItem) {
        // 设置选中条目的id
        if (anItem instanceof BigDecimal) {
            BigDecimal curr = (BigDecimal) anItem;
            seletedID = curr.subtract(super.start).divide(super.step, 2, RoundingMode.HALF_DOWN).intValue();
        }

    }

    @Override
    public Object getSelectedItem() {
        // 获取条目选中的内容
        BigDecimal item = new BigDecimal(seletedID).multiply(super.step).add(super.start).setScale(1,
                RoundingMode.HALF_DOWN);
        return item;
    }

}