几个简单的JAVA GUI练习 | 帆的自留地

最近在听 NEU 的 JAVA 慕课，然后有两个简单的 GUI 课后练习：

菜单栏相关练习

编写如图所示应用程序，单击选择菜单项退出后，显示下面的请选择对话框，选择是结束程序，选择否显示下面的消息对话框。

题目要求使用菜单栏 JMenuBar 和 菜单项 JMenuItem， 很遗憾 IEDA 所提供的 SwingGUIdesigner 并没有默认提高 菜单栏 和 菜单项的选则。因此这里被迫使用了 JFormDesigner 来创建可视化界面：

这里，题目要求的两个 optionPane 也是可以先在 jFromDesinger 中先画好的。这样就可以不用手动初始化了。

至此，系统自动生成的代码如下：

private void initComponents() {
    // JFormDesigner - Component initialization - DO NOT MODIFY  //GEN-BEGIN:initComponents
    menuBar1 = new JMenuBar();
    menuFile = new JMenu();
    menuItemOpen = new JMenuItem();
    menuItemExit = new JMenuItem();
    menuEidt = new JMenu();
    menuForm = new JMenu();
    optionPaneChoose = new JOptionPane();
    optionPaneNo = new JOptionPane();

    //======== this ========
    setTitle("EmptinessBoy\u4f5c\u4e1a");
    Container contentPane = getContentPane();
    contentPane.setLayout(new GridLayout(3, 4));

    //======== menuBar1 ========
    {

        //======== menuFile ========
        {
            menuFile.setText("\u6587\u4ef6");

            //---- menuItemOpen ----
            menuItemOpen.setText("\u6253\u5f00");
            menuFile.add(menuItemOpen);

            //---- menuItemExit ----
            menuItemExit.setText("\u9000\u51fa");
            menuItemExit.addActionListener(e -> menuItemExitActionPerformed(e));
            menuFile.add(menuItemExit);
        }
        menuBar1.add(menuFile);

        //======== menuEidt ========
        {
            menuEidt.setText("\u7f16\u8f91");
        }
        menuBar1.add(menuEidt);

        //======== menuForm ========
        {
            menuForm.setText("\u7a97\u53e3");
        }
        menuBar1.add(menuForm);
    }
    setJMenuBar(menuBar1);
    setSize(445, 315);
    setLocationRelativeTo(getOwner());
    // JFormDesigner - End of component initialization  //GEN-END:initComponents
}

// JFormDesigner - Variables declaration - DO NOT MODIFY  //GEN-BEGIN:variables
private JMenuBar menuBar1;
private JMenu menuFile;
private JMenuItem menuItemOpen;
private JMenuItem menuItemExit;
private JMenu menuEidt;
private JMenu menuForm;
private JOptionPane optionPaneChoose;
private JOptionPane optionPaneNo;
// JFormDesigner - End of variables declaration  //GEN-END:variables

为了使程序完成题目要求的功能，我们需要给菜单项 JMenuItem【menuItemExit】设置监听器。

事件监听代码：

optionPane 对话框写法

private void menuItemExitActionPerformed(ActionEvent e) {
    // TODO add your code here
    int i = optionPaneChoose.showConfirmDialog(null,"是否退出系统？","请选择", JOptionPane.YES_NO_OPTION);
    if(i==0)
        System.exit(0);
    else{
        //ConfirmDialog(null,"您选择了否！","消息",JOptionPane.YES_OPTION);
        optionPaneNo.showMessageDialog(null,"您选择了否","消息", JOptionPane.YES_OPTION);
    }
}

对于多选对话框，int i 的返回值就是指代了用户选中的 “是” 或 “否” 的值。一般情况下，选中是为 0.

optionPaneNo.showMessageDialog 显示一个消息提示
optionPaneChoose.showConfirmDialog 显示可确认对话框

设置点击关闭窗体的默认事件

只要在实现 JFrame 类的构造函数中加入一条

setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);

即可轻松搞定。

最后，整体运行效果：

窗体相关练习

窗体中显示一个图片，用鼠标可以拖动图片到任意位置。

没错，作业只有这么简简单单一句话。然后我也天真的以为这是一道秒杀题。但是，往往是我太天真了（悲哀

头里的步骤并不难，这里使用 JFormDesigner 创建窗体。然后随便拖拽一个 JLable 用来存放图片。

下面是系统自动生成的代码（含后面加的监听器）：

……
    private void initComponents() {
        // JFormDesigner - Component initialization - DO NOT MODIFY  //GEN-BEGIN:initComponents
        label1 = new JLabel();
        textField1 = new JTextField();

        //======== this ========
        setMinimumSize(new Dimension(500, 500));
        setTitle("EmptinessBoyMooc\u4f5c\u4e1a");
        var contentPane = getContentPane();

        //---- label1 ----
        label1.setIcon(null);
        label1.addMouseMotionListener(new MouseMotionAdapter() {
            @Override
            public void mouseDragged(MouseEvent e) {
                label1MouseDragged(e);
            }
        });
        label1.addMouseListener(new MouseAdapter() {
            @Override
            public void mousePressed(MouseEvent e) {
                label1MousePressed(e);
            }
        });

        //---- textField1 ----
        textField1.setText("\u6b64\u5904\u663e\u793a\u5750\u6807");

        GroupLayout contentPaneLayout = new GroupLayout(contentPane);
        contentPane.setLayout(contentPaneLayout);
        contentPaneLayout.setHorizontalGroup(
            contentPaneLayout.createParallelGroup()
                .addGroup(contentPaneLayout.createSequentialGroup()
                    .addGroup(contentPaneLayout.createParallelGroup(GroupLayout.Alignment.LEADING, false)
                        .addComponent(label1, GroupLayout.PREFERRED_SIZE, 100, GroupLayout.PREFERRED_SIZE)
                        .addGroup(contentPaneLayout.createSequentialGroup()
                            .addContainerGap()
                            .addComponent(textField1)))
                    .addContainerGap())
        );
        contentPaneLayout.setVerticalGroup(
            contentPaneLayout.createParallelGroup()
                .addGroup(contentPaneLayout.createSequentialGroup()
                    .addComponent(label1, GroupLayout.PREFERRED_SIZE, 100, GroupLayout.PREFERRED_SIZE)
                    .addPreferredGap(LayoutStyle.ComponentPlacement.RELATED, 302, Short.MAX_VALUE)
                    .addComponent(textField1, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
                    .addContainerGap())
        );
        pack();
        setLocationRelativeTo(getOwner());
        // JFormDesigner - End of component initialization  //GEN-END:initComponents
    }

    // JFormDesigner - Variables declaration - DO NOT MODIFY  //GEN-BEGIN:variables
    private JLabel label1;
    private JTextField textField1;
    // JFormDesigner - End of variables declaration  //GEN-END:variables
}

到这里，我们需要给 jlable 设置 icon，这里将设置 icon 的代码放到构造函数中：

Jlabel 设置 icon 方法

public MovePic() {
    initComponents();
    setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
    ImageIcon i = new ImageIcon("src/logo.png");
    Image pic = i.getImage().getScaledInstance(100,100,Image.SCALE_DEFAULT);
    ImageIcon ico = new ImageIcon(pic);
    label1.setIcon(ico);
}

现在是不是只要给 存放了图片的 jlable 设置 MouseDragged 鼠标拖拽监听函数呢？

最开始一脸小白的我确实是这么想的，然后写下了简单的

错误代码：
x = e.getX();
y = e.getY();
textField1.setText(x+","+y);
label1.setLocation(x,y);

网上都说了 e.getX(); e.getY(); 不就是获取当前是鼠标位置嘛。（呵呵

然而在实际测试中发现，实际上，这两个获取到的都是以 jlable 为容器，鼠标在 jlable 中的相对位置。因此单纯这样的代码无法实现所需要的功能。

那么，一心想偷懒的我想，那么只要针对 Jlable 的父容器设置鼠标监听器来改变坐标不就完了？（理想很美好，现实确是：

因为子容器遮挡了父容器，当鼠标移动到 Jlable 上时，设置在父容器 JFrame 的监听器就失效了！！

只有鼠标移出图片的时候，才能正确获取针对窗体的坐标。

终极坐标解决方案

那么只能使出大杀器了，（用我小学的算数水平，通过绝对坐标加减来获取位置了

经过查找文档，可知：

e.getXOnScreen() e.getYOnScreen() 可以用来获取鼠标在整个屏幕的绝对位置，而 this.getX() this.getY()可以获得当前窗体在屏幕中的左上角位置。

那么？！

只要使用 x = e.getXOnScreen()-this.getX() 就可以通过计算获得鼠标在窗体内部的相对位置啦！！！

但是这时候还是有些小小的瑕疵 ——鼠标拖拽后，显示的位置是以鼠标结束位置作为左上角定点的，拖拽感觉不够自然。

修复的方法很简单。既然 e.getX() 可以获取当前鼠标相对于图片（jlable）的相对位置，那么只要在我们刚才获取的 x 减去 这个内部的相对位置就完美啦！！注意这个坐标需要在刚开始按下鼠标时获取才有用，因此需要放在 MousePressed 监听器中。

最后附上代码：

public class MovePic extends JFrame {
    int x,y,a,b;
    public static void main(String[] args) {
        new MovePic().setVisible(true);
    }
    public MovePic() {
        initComponents();
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        ImageIcon i = new ImageIcon("src/logo.png");
        Image pic = i.getImage().getScaledInstance(100,100,Image.SCALE_DEFAULT);
        ImageIcon ico = new ImageIcon(pic);
        label1.setIcon(ico);
    }

    private void label1MouseDragged(MouseEvent e) {
        // TODO add your code here
        x = e.getXOnScreen()-this.getX()-a;
        y = e.getYOnScreen()-this.getY()-b-20;
        textField1.setText(x+","+y);
        label1.setLocation(x,y);
    }


    private void label1MousePressed(MouseEvent e) {
        // TODO add your code here
        a = e.getX();
        b = e.getY();
    }
……

运行效果：

nice！又是洗洗睡的一天（PS，最近腰疼犯了，睡觉保命要紧【滑稽】

控件和监听器练习

题目要求：使用 Java 实现一个RGB调色板程序，点击加减按钮可以调整RGB数值并显示颜色

由于已经比较习惯了 JFormDesigner 那么完成这个任务也靠Ta啦！

设计界面

这里外层的 Jframe 使用了 IntelijGridLayOut ，比起标准的 GridLayout 可以自由调整 margin，以及内部的浮动（有点像安卓里的 Gravaty

内部划分了两个 panel 用于摆放控件，下方的 panel 则用来显示实时的颜色输出

划分完成 UI ，并设置完成事件监听器后，系统就自动生成了 UI 相关的代码

……
    private void initComponents() {
        // JFormDesigner - Component initialization - DO NOT MODIFY  //GEN-BEGIN:initComponents
        panelSetColor = new JPanel();
        labelRed = new JLabel();
        buttonSubRed = new JButton();
        textFieldRed = new JTextField();
        buttonAddRed = new JButton();
        labelGreen = new JLabel();
        buttonSubGreen = new JButton();
        textFieldGreen = new JTextField();
        buttonAddGreen = new JButton();
        labelBlue = new JLabel();
        buttonSubBlue = new JButton();
        textFieldBlue = new JTextField();
        buttonAddBlue = new JButton();
        panelColor = new JPanel();
        labelShowColor = new JLabel();

        //======== this ========
        setTitle("2018010587-\u80e1\u6653\u5e06\uff08\u8c03\u8272\u677f\uff09");
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setMinimumSize(new Dimension(550, 350));
        setFont(new Font(Font.DIALOG, Font.PLAIN, 16));
        setBackground(Color.white);
        Container contentPane = getContentPane();
        contentPane.setLayout(new GridLayoutManager(4, 1, new Insets(0, 20, 20, 20), 0, 5));

        //======== panelSetColor ========
        {
            panelSetColor.setFont(panelSetColor.getFont().deriveFont(panelSetColor.getFont().getSize() + 4f));
            panelSetColor.setLayout(new GridLayoutManager(3, 4, new Insets(20, 0, 10, 0), 3, 3));

            //---- labelRed ----
            labelRed.setText("\u7ea2\u8272 R");
            labelRed.setForeground(Color.red);
            labelRed.setFont(labelRed.getFont().deriveFont(labelRed.getFont().getStyle() | Font.BOLD, labelRed.getFont().getSize() + 4f));
            panelSetColor.add(labelRed, new GridConstraints(0, 0, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_NONE,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- buttonSubRed ----
            buttonSubRed.setText("\u51cf\u5c11");
            buttonSubRed.setFont(buttonSubRed.getFont().deriveFont(buttonSubRed.getFont().getSize() + 4f));
            buttonSubRed.addActionListener(e -> buttonSubRedActionPerformed(e));
            panelSetColor.add(buttonSubRed, new GridConstraints(0, 1, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_NONE,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- textFieldRed ----
            textFieldRed.setText("155");
            textFieldRed.setFont(textFieldRed.getFont().deriveFont(textFieldRed.getFont().getSize() + 4f));
            panelSetColor.add(textFieldRed, new GridConstraints(0, 2, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_HORIZONTAL,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- buttonAddRed ----
            buttonAddRed.setText("\u589e\u52a0");
            buttonAddRed.setFont(buttonAddRed.getFont().deriveFont(buttonAddRed.getFont().getSize() + 4f));
            buttonAddRed.addActionListener(e -> buttonAddRedActionPerformed(e));
            panelSetColor.add(buttonAddRed, new GridConstraints(0, 3, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_NONE,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- labelGreen ----
            labelGreen.setText("\u7eff\u8272 G");
            labelGreen.setForeground(new Color(0, 204, 51));
            labelGreen.setFont(labelGreen.getFont().deriveFont(labelGreen.getFont().getStyle() | Font.BOLD, labelGreen.getFont().getSize() + 4f));
            panelSetColor.add(labelGreen, new GridConstraints(1, 0, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_NONE,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- buttonSubGreen ----
            buttonSubGreen.setText("\u51cf\u5c11");
            buttonSubGreen.setFont(buttonSubGreen.getFont().deriveFont(buttonSubGreen.getFont().getSize() + 4f));
            buttonSubGreen.addActionListener(e -> buttonSubGreenActionPerformed(e));
            panelSetColor.add(buttonSubGreen, new GridConstraints(1, 1, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_NONE,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- textFieldGreen ----
            textFieldGreen.setText("155");
            textFieldGreen.setFont(textFieldGreen.getFont().deriveFont(textFieldGreen.getFont().getSize() + 4f));
            panelSetColor.add(textFieldGreen, new GridConstraints(1, 2, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_HORIZONTAL,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- buttonAddGreen ----
            buttonAddGreen.setText("\u589e\u52a0");
            buttonAddGreen.setFont(buttonAddGreen.getFont().deriveFont(buttonAddGreen.getFont().getSize() + 4f));
            buttonAddGreen.addActionListener(e -> buttonAddGreenActionPerformed(e));
            panelSetColor.add(buttonAddGreen, new GridConstraints(1, 3, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_NONE,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- labelBlue ----
            labelBlue.setText("\u84dd\u8272 B");
            labelBlue.setForeground(new Color(0, 102, 255));
            labelBlue.setFont(labelBlue.getFont().deriveFont(labelBlue.getFont().getStyle() | Font.BOLD, labelBlue.getFont().getSize() + 4f));
            panelSetColor.add(labelBlue, new GridConstraints(2, 0, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_NONE,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- buttonSubBlue ----
            buttonSubBlue.setText("\u51cf\u5c11");
            buttonSubBlue.setFont(buttonSubBlue.getFont().deriveFont(buttonSubBlue.getFont().getSize() + 4f));
            buttonSubBlue.addActionListener(e -> buttonSubBlueActionPerformed(e));
            panelSetColor.add(buttonSubBlue, new GridConstraints(2, 1, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_NONE,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- textFieldBlue ----
            textFieldBlue.setText("155");
            textFieldBlue.setFont(textFieldBlue.getFont().deriveFont(textFieldBlue.getFont().getSize() + 4f));
            panelSetColor.add(textFieldBlue, new GridConstraints(2, 2, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_HORIZONTAL,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- buttonAddBlue ----
            buttonAddBlue.setText("\u589e\u52a0");
            buttonAddBlue.setFont(buttonAddBlue.getFont().deriveFont(buttonAddBlue.getFont().getSize() + 4f));
            buttonAddBlue.addActionListener(e -> buttonAddBlueActionPerformed(e));
            panelSetColor.add(buttonAddBlue, new GridConstraints(2, 3, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_NONE,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));
        }
        contentPane.add(panelSetColor, new GridConstraints(0, 0, 1, 1,
            GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_BOTH,
            GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
            GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
            null, null, null));

        //======== panelColor ========
        {
            panelColor.setLayout(new GridLayoutManager(1, 1, new Insets(0, 10, 0, 10), 0, 0));

            //---- labelShowColor ----
            labelShowColor.setText("\u6b64\u5904\u663e\u793a\u6700\u7ec8\u989c\u8272");
            panelColor.add(labelShowColor, new GridConstraints(0, 0, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_NONE,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));
        }
        contentPane.add(panelColor, new GridConstraints(2, 0, 1, 1,
            GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_BOTH,
            GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
            GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
            null, null, null));
        pack();
        setLocationRelativeTo(getOwner());
        // JFormDesigner - End of component initialization  //GEN-END:initComponents
    }

    // JFormDesigner - Variables declaration - DO NOT MODIFY  //GEN-BEGIN:variables
    private JPanel panelSetColor;
    private JLabel labelRed;
    private JButton buttonSubRed;
    private JTextField textFieldRed;
    private JButton buttonAddRed;
    private JLabel labelGreen;
    private JButton buttonSubGreen;
    private JTextField textFieldGreen;
    private JButton buttonAddGreen;
    private JLabel labelBlue;
    private JButton buttonSubBlue;
    private JTextField textFieldBlue;
    private JButton buttonAddBlue;
    private JPanel panelColor;
    private JLabel labelShowColor;
    // JFormDesigner - End of variables declaration  //GEN-END:variables
}

核心代码

第一步要解决的就是程序刚运行时显示的颜色。这里我给类创建了r,g,b三个整型的变量。

然后只要在构造函数中把 panel 的颜色设置成预设的 rgb 即可。这里使用了 .setBackground 方法来设置背景色值。

public class ColorPanel extends JFrame {
    int r=155,g=155,b=155;
    Color bgColor = new Color(r, g, b);//设置初始颜色
……

public ColorPanel() {
    initComponents();
    textFieldRed.setText(String.valueOf(r));
    textFieldGreen.setText(String.valueOf(g));
    textFieldBlue.setText(String.valueOf(b));
    panelColor.setBackground(bgColor);
}

接下来就是要通过按钮的按动来改变颜色了，这里以红色减少按钮为例：

private void buttonSubRedActionPerformed(ActionEvent e) {
    // TODO add your code here
    GetNum();
    if(r>0&&r<=255)
        r--;
    else
        System.out.println("红色已到临界值");
    ShowColor();
}

这段代码中，使用了我写的两个函数 GetNum() 和 ShowColor()。GetNum 的目的是获取两个按钮中的文本框的值，来允许程序运行的时候可以手动输入数值。而 showColor 则是因为每个按钮最后都有显示颜色的功能，这段代码可以用函数来做。

GetNum()：

void GetNum(){
    //允许用户输入数值修改rgb
    r = Integer.parseInt(textFieldRed.getText());
    g = Integer.parseInt(textFieldGreen.getText());
    b = Integer.parseInt(textFieldBlue.getText());
}

ShowColor()：

void ShowColor(){
    textFieldRed.setText(String.valueOf(r));
    textFieldGreen.setText(String.valueOf(g));
    textFieldBlue.setText(String.valueOf(b));
    bgColor = new Color(r,g,b);
    panelColor.setBackground(bgColor);
    panelColor.setBackground(bgColor);
    labelShowColor.setText("当前颜色16进制为：#"+Integer.toHexString(r)+Integer.toHexString(g)+Integer.toHexString(b));
}

最后附上运行效果：

完整代码：

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import com.intellij.uiDesigner.core.*;

/**
 * @author huxiaofan
 */
public class ColorPanel extends JFrame {
    int r=155,g=155,b=155;
    Color bgColor = new Color(r, g, b);//设置初始颜色
    public static void main(String[] args) {
        new ColorPanel().setVisible(true);


    }
    public ColorPanel() {
        initComponents();
        textFieldRed.setText(String.valueOf(r));
        textFieldGreen.setText(String.valueOf(g));
        textFieldBlue.setText(String.valueOf(b));
        panelColor.setBackground(bgColor);
    }

    void ShowColor(){
        textFieldRed.setText(String.valueOf(r));
        textFieldGreen.setText(String.valueOf(g));
        textFieldBlue.setText(String.valueOf(b));
        bgColor = new Color(r,g,b);
        panelColor.setBackground(bgColor);
        panelColor.setBackground(bgColor);
        labelShowColor.setText("当前颜色16进制为：#"+Integer.toHexString(r)+Integer.toHexString(g)+Integer.toHexString(b));
    }

    void GetNum(){
        //允许用户输入数值修改rgb
        r = Integer.parseInt(textFieldRed.getText());
        g = Integer.parseInt(textFieldGreen.getText());
        b = Integer.parseInt(textFieldBlue.getText());
    }

    private void buttonSubRedActionPerformed(ActionEvent e) {
        // TODO add your code here
        GetNum();
        if(r>0&&r<=255)
            r--;
        else
            System.out.println("红色已到临界值");
        ShowColor();
    }

    private void buttonAddRedActionPerformed(ActionEvent e) {
        // TODO add your code here
        GetNum();
        if(r>=0&&r<255)
            r++;
        else
            System.out.println("红色已到临界值");
        ShowColor();
    }

    private void buttonSubGreenActionPerformed(ActionEvent e) {
        // TODO add your code here
        GetNum();
        if(g>0&&g<=255)
            g--;
        else
            System.out.println("绿色已到临界值");
        ShowColor();
    }

    private void buttonAddGreenActionPerformed(ActionEvent e) {
        // TODO add your code here
        GetNum();
        if(g>=0&&g<255)
            g++;
        else
            System.out.println("绿色已到临界值");
        ShowColor();
    }

    private void buttonSubBlueActionPerformed(ActionEvent e) {
        // TODO add your code here
        GetNum();
        if(b>0&&b<=255)
            b--;
        else
            System.out.println("蓝色已到临界值");
        ShowColor();
    }

    private void buttonAddBlueActionPerformed(ActionEvent e) {
        // TODO add your code here
        GetNum();
        if(b>=0&&b<255)
            b++;
        else
            System.out.println("蓝色已到临界值");
        ShowColor();
    }



    private void initComponents() {
        // JFormDesigner - Component initialization - DO NOT MODIFY  //GEN-BEGIN:initComponents
        panelSetColor = new JPanel();
        labelRed = new JLabel();
        buttonSubRed = new JButton();
        textFieldRed = new JTextField();
        buttonAddRed = new JButton();
        labelGreen = new JLabel();
        buttonSubGreen = new JButton();
        textFieldGreen = new JTextField();
        buttonAddGreen = new JButton();
        labelBlue = new JLabel();
        buttonSubBlue = new JButton();
        textFieldBlue = new JTextField();
        buttonAddBlue = new JButton();
        panelColor = new JPanel();
        labelShowColor = new JLabel();

        //======== this ========
        setTitle("2018010587-\u80e1\u6653\u5e06\uff08\u8c03\u8272\u677f\uff09");
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setMinimumSize(new Dimension(550, 350));
        setFont(new Font(Font.DIALOG, Font.PLAIN, 16));
        setBackground(Color.white);
        Container contentPane = getContentPane();
        contentPane.setLayout(new GridLayoutManager(4, 1, new Insets(0, 20, 20, 20), 0, 5));

        //======== panelSetColor ========
        {
            panelSetColor.setFont(panelSetColor.getFont().deriveFont(panelSetColor.getFont().getSize() + 4f));
            panelSetColor.setLayout(new GridLayoutManager(3, 4, new Insets(20, 0, 10, 0), 3, 3));

            //---- labelRed ----
            labelRed.setText("\u7ea2\u8272 R");
            labelRed.setForeground(Color.red);
            labelRed.setFont(labelRed.getFont().deriveFont(labelRed.getFont().getStyle() | Font.BOLD, labelRed.getFont().getSize() + 4f));
            panelSetColor.add(labelRed, new GridConstraints(0, 0, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_NONE,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- buttonSubRed ----
            buttonSubRed.setText("\u51cf\u5c11");
            buttonSubRed.setFont(buttonSubRed.getFont().deriveFont(buttonSubRed.getFont().getSize() + 4f));
            buttonSubRed.addActionListener(e -> buttonSubRedActionPerformed(e));
            panelSetColor.add(buttonSubRed, new GridConstraints(0, 1, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_NONE,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- textFieldRed ----
            textFieldRed.setText("155");
            textFieldRed.setFont(textFieldRed.getFont().deriveFont(textFieldRed.getFont().getSize() + 4f));
            panelSetColor.add(textFieldRed, new GridConstraints(0, 2, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_HORIZONTAL,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- buttonAddRed ----
            buttonAddRed.setText("\u589e\u52a0");
            buttonAddRed.setFont(buttonAddRed.getFont().deriveFont(buttonAddRed.getFont().getSize() + 4f));
            buttonAddRed.addActionListener(e -> buttonAddRedActionPerformed(e));
            panelSetColor.add(buttonAddRed, new GridConstraints(0, 3, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_NONE,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- labelGreen ----
            labelGreen.setText("\u7eff\u8272 G");
            labelGreen.setForeground(new Color(0, 204, 51));
            labelGreen.setFont(labelGreen.getFont().deriveFont(labelGreen.getFont().getStyle() | Font.BOLD, labelGreen.getFont().getSize() + 4f));
            panelSetColor.add(labelGreen, new GridConstraints(1, 0, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_NONE,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- buttonSubGreen ----
            buttonSubGreen.setText("\u51cf\u5c11");
            buttonSubGreen.setFont(buttonSubGreen.getFont().deriveFont(buttonSubGreen.getFont().getSize() + 4f));
            buttonSubGreen.addActionListener(e -> buttonSubGreenActionPerformed(e));
            panelSetColor.add(buttonSubGreen, new GridConstraints(1, 1, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_NONE,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- textFieldGreen ----
            textFieldGreen.setText("155");
            textFieldGreen.setFont(textFieldGreen.getFont().deriveFont(textFieldGreen.getFont().getSize() + 4f));
            panelSetColor.add(textFieldGreen, new GridConstraints(1, 2, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_HORIZONTAL,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- buttonAddGreen ----
            buttonAddGreen.setText("\u589e\u52a0");
            buttonAddGreen.setFont(buttonAddGreen.getFont().deriveFont(buttonAddGreen.getFont().getSize() + 4f));
            buttonAddGreen.addActionListener(e -> buttonAddGreenActionPerformed(e));
            panelSetColor.add(buttonAddGreen, new GridConstraints(1, 3, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_NONE,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- labelBlue ----
            labelBlue.setText("\u84dd\u8272 B");
            labelBlue.setForeground(new Color(0, 102, 255));
            labelBlue.setFont(labelBlue.getFont().deriveFont(labelBlue.getFont().getStyle() | Font.BOLD, labelBlue.getFont().getSize() + 4f));
            panelSetColor.add(labelBlue, new GridConstraints(2, 0, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_NONE,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- buttonSubBlue ----
            buttonSubBlue.setText("\u51cf\u5c11");
            buttonSubBlue.setFont(buttonSubBlue.getFont().deriveFont(buttonSubBlue.getFont().getSize() + 4f));
            buttonSubBlue.addActionListener(e -> buttonSubBlueActionPerformed(e));
            panelSetColor.add(buttonSubBlue, new GridConstraints(2, 1, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_NONE,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- textFieldBlue ----
            textFieldBlue.setText("155");
            textFieldBlue.setFont(textFieldBlue.getFont().deriveFont(textFieldBlue.getFont().getSize() + 4f));
            panelSetColor.add(textFieldBlue, new GridConstraints(2, 2, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_HORIZONTAL,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- buttonAddBlue ----
            buttonAddBlue.setText("\u589e\u52a0");
            buttonAddBlue.setFont(buttonAddBlue.getFont().deriveFont(buttonAddBlue.getFont().getSize() + 4f));
            buttonAddBlue.addActionListener(e -> buttonAddBlueActionPerformed(e));
            panelSetColor.add(buttonAddBlue, new GridConstraints(2, 3, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_NONE,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));
        }
        contentPane.add(panelSetColor, new GridConstraints(0, 0, 1, 1,
            GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_BOTH,
            GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
            GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
            null, null, null));

        //======== panelColor ========
        {
            panelColor.setLayout(new GridLayoutManager(1, 1, new Insets(0, 10, 0, 10), 0, 0));

            //---- labelShowColor ----
            labelShowColor.setText("\u6b64\u5904\u663e\u793a\u6700\u7ec8\u989c\u8272");
            panelColor.add(labelShowColor, new GridConstraints(0, 0, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_NONE,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));
        }
        contentPane.add(panelColor, new GridConstraints(2, 0, 1, 1,
            GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_BOTH,
            GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
            GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
            null, null, null));
        pack();
        setLocationRelativeTo(getOwner());
        // JFormDesigner - End of component initialization  //GEN-END:initComponents
    }

    // JFormDesigner - Variables declaration - DO NOT MODIFY  //GEN-BEGIN:variables
    private JPanel panelSetColor;
    private JLabel labelRed;
    private JButton buttonSubRed;
    private JTextField textFieldRed;
    private JButton buttonAddRed;
    private JLabel labelGreen;
    private JButton buttonSubGreen;
    private JTextField textFieldGreen;
    private JButton buttonAddGreen;
    private JLabel labelBlue;
    private JButton buttonSubBlue;
    private JTextField textFieldBlue;
    private JButton buttonAddBlue;
    private JPanel panelColor;
    private JLabel labelShowColor;
    // JFormDesigner - End of variables declaration  //GEN-END:variables
}

带IO操作的登录窗体

编写一个登录窗体，输入用户名和密码，验证通过显示登录成功的消息框，否则显示用户名或密码错误的消息框。用户名和密码存放在 c 盘 java 目录下的 login.txt 中，用文本信息存储，每行一个用户名和密码，用户名和密码用 # 分隔

核心代码

import java.awt.*;
import java.awt.event.*;
import java.io.*;
import java.util.Arrays;
import javax.swing.*;
import com.intellij.uiDesigner.core.*;

/**
 * @author huxiaofan
 */
public class loginPanel extends JFrame {

    File f = new File("login.txt"); //创建一个用于读取用户名密码的文件对象

    public static void main(String[] args) {
        new loginPanel().setVisible(true); //显示窗体
    }
    public loginPanel() {
        initComponents();
    }

    private void buttonLoginActionPerformed(ActionEvent e) {
        // TODO add your code here
        if(doLogin())
            optionPaneok.showMessageDialog(null,"恭喜你登录成功！","登录成功",JOptionPane.INFORMATION_MESSAGE); //显示成功弹窗
        else
            optionPanefail.showMessageDialog(null, "用户名密码错误！", "登录失败",JOptionPane.ERROR_MESSAGE); //显示失败弹窗
    }

    boolean doLogin(){  //函数登录成功返回 true
        try {
            BufferedReader br = new BufferedReader(new FileReader(f));  //新建字符缓冲流
            String u = textFieldUserName.getText();  //获取用户输入在文本框的用户名
            String p = String.valueOf(passwordFieldPass.getPassword());  //获取用户输入在密码框的密码，要把原始的字符数组用 String.valueOf() 方法转为字符串
            String s;  //存放临时读取的每一行字符串
            while((s = br.readLine())!=null){
                String[] temp = s.split("#");  //拆分字符串
                if(temp[0].equals(u)&&temp[1].equals(p)){
                    System.out.println("登录成功");
                    return true;
                }
            }
            br.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
        return false;
    }

    private void button2ActionPerformed(ActionEvent e) {
        // TODO add your code here
    }
……

UI自动生成代码

……
    private void initComponents() {
        // JFormDesigner - Component initialization - DO NOT MODIFY  //GEN-BEGIN:initComponents
        panel1 = new JPanel();
        labelUser = new JLabel();
        textFieldUserName = new JTextField();
        labelPass = new JLabel();
        passwordFieldPass = new JPasswordField();
        buttonLogin = new JButton();
        optionPaneok = new JOptionPane();
        optionPanefail = new JOptionPane();

        //======== this ========
        setTitle("Emptinessboy \u6155\u8bfeIO\u4f5c\u4e1a");
        setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        setMinimumSize(new Dimension(420, 250));
        Container contentPane = getContentPane();
        contentPane.setLayout(new GridLayoutManager(2, 1, new Insets(0, 0, 5, 0), -1, -1));

        //======== panel1 ========
        {
            panel1.setMinimumSize(new Dimension(180, 90));
            panel1.setLayout(new GridLayoutManager(2, 2, new Insets(10, 30, 10, 60), 0, 10));

            //---- labelUser ----
            labelUser.setText("\u7528\u6237\u540d \uff1a");
            labelUser.setFont(labelUser.getFont().deriveFont(labelUser.getFont().getStyle() | Font.BOLD, labelUser.getFont().getSize() + 3f));
            panel1.add(labelUser, new GridConstraints(0, 0, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_NONE,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- textFieldUserName ----
            textFieldUserName.setFont(textFieldUserName.getFont().deriveFont(textFieldUserName.getFont().getSize() + 3f));
            panel1.add(textFieldUserName, new GridConstraints(0, 1, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_HORIZONTAL,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- labelPass ----
            labelPass.setText("\u5bc6   \u7801 \uff1a");
            labelPass.setFont(labelPass.getFont().deriveFont(labelPass.getFont().getStyle() | Font.BOLD, labelPass.getFont().getSize() + 3f));
            panel1.add(labelPass, new GridConstraints(1, 0, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_NONE,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));

            //---- passwordFieldPass ----
            passwordFieldPass.setFont(passwordFieldPass.getFont().deriveFont(passwordFieldPass.getFont().getSize() + 3f));
            panel1.add(passwordFieldPass, new GridConstraints(1, 1, 1, 1,
                GridConstraints.ANCHOR_CENTER, GridConstraints.FILL_HORIZONTAL,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
                null, null, null));
        }
        contentPane.add(panel1, new GridConstraints(0, 0, 1, 1,
            GridConstraints.ANCHOR_SOUTH, GridConstraints.FILL_HORIZONTAL,
            GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
            GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
            null, null, null));

        //---- buttonLogin ----
        buttonLogin.setText("\u767b \u5f55");
        buttonLogin.setVerticalTextPosition(SwingConstants.TOP);
        buttonLogin.setFont(buttonLogin.getFont().deriveFont(buttonLogin.getFont().getStyle() | Font.BOLD, buttonLogin.getFont().getSize() + 3f));
        buttonLogin.addActionListener(e -> {
            button2ActionPerformed(e);
            buttonLoginActionPerformed(e);
        });
        contentPane.add(buttonLogin, new GridConstraints(1, 0, 1, 1,
            GridConstraints.ANCHOR_NORTH, GridConstraints.FILL_NONE,
            GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
            GridConstraints.SIZEPOLICY_CAN_SHRINK | GridConstraints.SIZEPOLICY_CAN_GROW,
            null, null, null));
        pack();
        setLocationRelativeTo(getOwner());

        //---- optionPaneok ----
        optionPaneok.setIcon(UIManager.getIcon("OptionPane.informationIcon"));
        optionPaneok.setMessageType(JOptionPane.INFORMATION_MESSAGE);

        //---- optionPanefail ----
        optionPanefail.setIcon(UIManager.getIcon("OptionPane.errorIcon"));
        optionPanefail.setMessageType(JOptionPane.ERROR_MESSAGE);
        // JFormDesigner - End of component initialization  //GEN-END:initComponents
    }

    // JFormDesigner - Variables declaration - DO NOT MODIFY  //GEN-BEGIN:variables
    private JPanel panel1;
    private JLabel labelUser;
    private JTextField textFieldUserName;
    private JLabel labelPass;
    private JPasswordField passwordFieldPass;
    private JButton buttonLogin;
    private JOptionPane optionPaneok;
    private JOptionPane optionPanefail;
    // JFormDesigner - End of variables declaration  //GEN-END:variables
}

运行效果

This blog is under a CC BY-NC-ND 4.0 Unported License
本文链接：https://coding.emptinessboy.com/2020/05/%E5%87%A0%E4%B8%AA%E7%AE%80%E5%8D%95%E7%9A%84JAVA-GUI%E7%BB%83%E4%B9%A0/