一.GUI
(1)GUI是：用图形的方式，来显示计算机操作的界面。
(2)javax.swing包
在awt的基础上，建立的一套图形界面系统，提供了更多的组件，而且完全由Java实现。增强了移植性，属轻量级控件
组件：是具有图形表示的对象，该图形表示可以显示在屏幕上并且可以与用户交互
(3)常用 GUI 组件
GUI组件
3.1 基本组件(JButton,JLabel,JTextField,JTextArea)
3.2容器组件( Window<–Frame<–JFrame || Panel<–JPanel)
(4)JFrame
4.1 JFrame概述
是一个顶层窗口
构造方法：
JFrame()构造一个最初不可见的新窗体
成员方法
void setVisible?(boolean b)：显示或隐藏此窗体具体取决于参数b的值
void setSize?(int width, int height)：调整此组件的大小，使其宽度为width，高度为height，单位是像素
void setTitle(String title)：设置窗体标题
void setLocationRelativeTo?(Component c)：设置位置，值为null，则窗体位于屏幕中央
void setDefaultCloseOperation?(int operation)：设置窗体关闭时默认操作整数3表示：窗口关闭时退出应用程序
void setAlwaysOnTop(boolean alwaysOnTop)：设置此窗口是否应始终位于其他窗口之上
4.2 JFrame简单案例

 public class JFrameDemo01 {public static void main(String[] args) {//1.构造一个最初不可见的新窗体JFrame jf = new JFrame();//2.设置窗体标题jf.setTitle("百度一下，你就知道");//3.设置窗体大小jf.setSize(400, 300);//4.设置窗体关闭时默认操作(整数3表示：窗口关闭时退出应用程序)jf.setDefaultCloseOperation(3);//5.设置位置，值为null，则窗体位于屏幕中央jf.setLocationRelativeTo(null);//6.设置此窗口是否应始终位于其他窗口之上jf.setAlwaysOnTop(true);//7.显示或隐藏此窗体具体取决于参数b的值jf.setVisible(true);}}

(5)JButton
5.1 JButton概述
按钮的实现
构造方法
JButton?(String text)：创建一个带文本的按钮
成员方法
void setSize?(int width, int height)：设置大小
void setLocation?(int x, int y)：设置位置(x坐标，y坐标)
void setBounds?(int x, int y, int width, int height)：设置位置和大小
和窗体相关操作
取消窗体默认布局：窗体对象.setLayout(null);
把按钮添加到窗体：窗体对象.add(按钮对象);
5.2 JButton简单案例

public class JButtonDemo {public static void main(String[] args) {//1.创建窗体对象JFrame jf = new JFrame();jf.setTitle("窗口中添加按钮");jf.setSize(400, 300);jf.setDefaultCloseOperation(3);jf.setLocationRelativeTo(null);jf.setAlwaysOnTop(true);//2.取消窗体的默认布局jf.setLayout(null); //3.创建一个带文本的按钮JButton btn = new JButton("我是按钮");//4.设置大小和设置位置(x坐标，y坐标)btn.setBounds(100,100,100,20);//5.把按钮添加到窗体jf.add(btn);//6.设置窗体可见jf.setVisible(true);}}

(6)JLabel
6.1 JLabel概述
短文本字符串或图像的显示区域
构造方法
JLabel(String text)：使用指定的文本创建 JLabel实例
JLabel(Icon image)：使用指定的图像创建 JLabel实例
ImageIcon?(String filename)：从指定的文件创建ImageIcon【文件路径：绝对路径和相对路径】
绝对路径：完整的路径名【D:\IdeaProjects\javase_code\itheima-api-gui\images\mn.png】
相对路径：必须使用取自其他路径名的信息进行解释【itheima-api-gui\images\mn.png】
成员方法
void setBounds?(int x, int y, int width, int height)：设置位置和大小
6.2 JLabel简单案例

public class JLabelDemo {public static void main(String[] args) {//1.创建窗体对象JFrame jf = new JFrame();jf.setTitle("显示文本和图像");jf.setSize(400, 300);jf.setDefaultCloseOperation(3);jf.setLocationRelativeTo(null);jf.setAlwaysOnTop(true);jf.setLayout(null);//2.使用指定的文本创建 JLabel实例JLabel jLabel = new JLabel("好好学习");jLabel.setBounds(0,0,100,20);//3.使用指定的图像创建 JLabel实例，从指定的文件创建ImageIconJLabel jLabel2 = new JLabel(new ImageIcon("itheima-api-gui\\images\\mn.png"));jLabel2.setBounds(50,50,100,143);//4.把文本添加到窗体jf.add(jLabel);jf.add(jLabel2);//5.设置窗体可见jf.setVisible(true);}}

(7)用户登录界面
/用户登录/

public class UserLogin {public static void main(String[] args) {//1.创建窗体对象JFrame jf = new JFrame();jf.setTitle("用户登录");jf.setSize(400, 300);jf.setDefaultCloseOperation(3);jf.setLocationRelativeTo(null);jf.setAlwaysOnTop(true);jf.setLayout(null);//2.显示用户名文本JLabel usernameLable = new JLabel("用户名");usernameLable.setBounds(50,50,50,20);jf.add(usernameLable);//3.用户名输入框JTextField usernameField = new JTextField();usernameField.setBounds(150,50,180,20);jf.add(usernameField);//4.显示密码文本JLabel passwordLable = new JLabel("密码");passwordLable.setBounds(50,100,50,20);jf.add(passwordLable);//5.密码输入框JPasswordField passwordField = new JPasswordField();passwordField.setBounds(150,100,180,20);jf.add(passwordField);//6.登录按钮JButton loginButton = new JButton("登录");loginButton.setBounds(50,200,280,20);jf.add(loginButton);//7.设置窗体可见jf.setVisible(true);}}

(8)聊天室界面

 public class ChatRoom {public static void main(String[] args) {//1.创建窗体对象JFrame jf = new JFrame();jf.setTitle("聊天室");jf.setSize(400, 300);jf.setDefaultCloseOperation(3);jf.setLocationRelativeTo(null);jf.setAlwaysOnTop(true);jf.setLayout(null);//2.显示聊天信息的文本域JTextArea messageArea = new JTextArea();messageArea.setBounds(10,10,360,200);jf.add(messageArea);//3.输入聊天信息的文本框JTextField messageField = new JTextField();messageField.setBounds(10,230,180,20);jf.add(messageField);//4.发送按钮JButton sendButton = new JButton("发送");sendButton.setBounds(200,230,70,20);jf.add(sendButton);//5.清空聊天按钮JButton clearButton = new JButton("清空聊天");clearButton.setBounds(280,230,100,20);jf.add(clearButton);//6.设置窗体可见jf.setVisible(true);}}

(9)考勤查询并使用日历控件

日历控件类：

import javax.swing.*;
import javax.swing.event.AncestorEvent;
import javax.swing.event.AncestorListener;
import java.awt.*;
import java.awt.event.*;
import java.text.SimpleDateFormat;
import java.util.List;
import java.util.*;/*** 日期选择器，可以指定日期的显示格式*/
public class DateChooser extends JPanel {private static final long serialVersionUID = 4529266044762990227L;private Date initDate;private Calendar now = Calendar.getInstance();private Calendar select;private JPanel monthPanel;// 月历private JP1 jp1;// 四块面板,组成private JP2 jp2;private JP3 jp3;private JP4 jp4;private Font font = new Font("宋体", Font.PLAIN, 12);private final LabelManager lm = new LabelManager();private SimpleDateFormat sdf;private boolean isShow = false;private Popup pop;private JComponent showDate;public static DateChooser getInstance() {return new DateChooser();}public static DateChooser getInstance(Date date) {return new DateChooser(date);}public static DateChooser getInstance(String format) {return new DateChooser(format);}public static DateChooser getInstance(Date date, String format) {return new DateChooser(date, format);}/*** Creates a new instance of DateChooser*/private DateChooser() {this(new Date());}private DateChooser(Date date) {this(date, "yyyy年MM月dd日");}private DateChooser(String format) {this(new Date(), format);}private DateChooser(Date date, String format) {initDate = date;sdf = new SimpleDateFormat(format);select = Calendar.getInstance();select.setTime(initDate);initPanel();}/*** 是否允许用户选择*/public void setEnabled(boolean b) {super.setEnabled(b);showDate.setEnabled(b);}/*** 得到当前选择框的日期*/public Date getDate() {return select.getTime();}public String getStrDate() {return sdf.format(select.getTime());}public String getStrDate(String format) {sdf = new SimpleDateFormat(format);return sdf.format(select.getTime());}// 根据初始化的日期,初始化面板private void initPanel() {monthPanel = new JPanel(new BorderLayout());monthPanel.setBorder(BorderFactory.createLineBorder(Color.BLUE));JPanel up = new JPanel(new BorderLayout());up.add(jp1 = new JP1(), BorderLayout.NORTH);up.add(jp2 = new JP2(), BorderLayout.CENTER);monthPanel.add(jp3 = new JP3(), BorderLayout.CENTER);monthPanel.add(up, BorderLayout.NORTH);monthPanel.add(jp4 = new JP4(), BorderLayout.SOUTH);this.addAncestorListener(new AncestorListener() {public void ancestorAdded(AncestorEvent event) {}public void ancestorRemoved(AncestorEvent event) {}// 只要祖先组件一移动,马上就让popup消失public void ancestorMoved(AncestorEvent event) {hidePanel();}});}public void register(final JComponent showDate) {this.showDate = showDate;showDate.setRequestFocusEnabled(true);showDate.addMouseListener(new MouseAdapter() {public void mousePressed(MouseEvent me) {showDate.requestFocusInWindow();}});this.setBackground(Color.WHITE);this.add(showDate, BorderLayout.CENTER);this.setPreferredSize(new Dimension(90, 25));this.setBorder(BorderFactory.createLineBorder(Color.GRAY));showDate.addMouseListener(new MouseAdapter() {public void mouseEntered(MouseEvent me) {if (showDate.isEnabled()) {showDate.setCursor(new Cursor(Cursor.HAND_CURSOR));showDate.setForeground(Color.RED);}}public void mouseExited(MouseEvent me) {if (showDate.isEnabled()) {showDate.setCursor(new Cursor(Cursor.DEFAULT_CURSOR));showDate.setForeground(Color.BLACK);}}public void mousePressed(MouseEvent me) {if (showDate.isEnabled()) {showDate.setForeground(Color.CYAN);if (isShow) {hidePanel();} else {showPanel(showDate);}}}public void mouseReleased(MouseEvent me) {if (showDate.isEnabled()) {showDate.setForeground(Color.BLACK);}}});showDate.addFocusListener(new FocusListener() {public void focusLost(FocusEvent e) {hidePanel();}public void focusGained(FocusEvent e) {}});}// 根据新的日期刷新private void refresh() {jp1.updateDate();jp2.updateDate();jp3.updateDate();jp4.updateDate();SwingUtilities.updateComponentTreeUI(this);}// 提交日期private void commit() {// TODO add other components hereif (showDate instanceof JTextField) {((JTextField) showDate).setText(sdf.format(select.getTime()));} else if (showDate instanceof JLabel) {((JLabel) showDate).setText(sdf.format(select.getTime()));}hidePanel();}// 隐藏日期选择面板private void hidePanel() {if (pop != null) {isShow = false;pop.hide();pop = null;}}// 显示日期选择面板private void showPanel(Component owner) {if (pop != null) {pop.hide();}Point show = new Point(0, showDate.getHeight());SwingUtilities.convertPointToScreen(show, showDate);Dimension size = Toolkit.getDefaultToolkit().getScreenSize();int x = show.x;int y = show.y;if (x < 0) {x = 0;}if (x > size.width - 295) {x = size.width - 295;}if (y < size.height - 170) {} else {y -= 188;}pop = PopupFactory.getSharedInstance().getPopup(owner, monthPanel, x, y);pop.show();isShow = true;}/*** 最上面的面板用来显示月份的增减*/private class JP1 extends JPanel {private static final long serialVersionUID = -5638853772805561174L;JLabel yearleft, yearright, monthleft, monthright, center,centercontainer;public JP1() {super(new BorderLayout());this.setBackground(new Color(160, 185, 215));initJP1();}private void initJP1() {yearleft = new JLabel("  <<", JLabel.CENTER);yearleft.setToolTipText("上一年");yearright = new JLabel(">>  ", JLabel.CENTER);yearright.setToolTipText("下一年");yearleft.setBorder(BorderFactory.createEmptyBorder(2, 0, 0, 0));yearright.setBorder(BorderFactory.createEmptyBorder(2, 0, 0, 0));monthleft = new JLabel("  <", JLabel.RIGHT);monthleft.setToolTipText("上一月");monthright = new JLabel(">  ", JLabel.LEFT);monthright.setToolTipText("下一月");monthleft.setBorder(BorderFactory.createEmptyBorder(2, 30, 0, 0));monthright.setBorder(BorderFactory.createEmptyBorder(2, 0, 0, 30));centercontainer = new JLabel("", JLabel.CENTER);centercontainer.setLayout(new BorderLayout());center = new JLabel("", JLabel.CENTER);centercontainer.add(monthleft, BorderLayout.WEST);centercontainer.add(center, BorderLayout.CENTER);centercontainer.add(monthright, BorderLayout.EAST);this.add(yearleft, BorderLayout.WEST);this.add(centercontainer, BorderLayout.CENTER);this.add(yearright, BorderLayout.EAST);this.setPreferredSize(new Dimension(295, 25));updateDate();yearleft.addMouseListener(new MouseAdapter() {public void mouseEntered(MouseEvent me) {yearleft.setCursor(new Cursor(Cursor.HAND_CURSOR));yearleft.setForeground(Color.RED);}public void mouseExited(MouseEvent me) {yearleft.setCursor(new Cursor(Cursor.DEFAULT_CURSOR));yearleft.setForeground(Color.BLACK);}public void mousePressed(MouseEvent me) {select.add(Calendar.YEAR, -1);yearleft.setForeground(Color.WHITE);refresh();}public void mouseReleased(MouseEvent me) {yearleft.setForeground(Color.BLACK);}});yearright.addMouseListener(new MouseAdapter() {public void mouseEntered(MouseEvent me) {yearright.setCursor(new Cursor(Cursor.HAND_CURSOR));yearright.setForeground(Color.RED);}public void mouseExited(MouseEvent me) {yearright.setCursor(new Cursor(Cursor.DEFAULT_CURSOR));yearright.setForeground(Color.BLACK);}public void mousePressed(MouseEvent me) {select.add(Calendar.YEAR, 1);yearright.setForeground(Color.WHITE);refresh();}public void mouseReleased(MouseEvent me) {yearright.setForeground(Color.BLACK);}});monthleft.addMouseListener(new MouseAdapter() {public void mouseEntered(MouseEvent me) {monthleft.setCursor(new Cursor(Cursor.HAND_CURSOR));monthleft.setForeground(Color.RED);}public void mouseExited(MouseEvent me) {monthleft.setCursor(new Cursor(Cursor.DEFAULT_CURSOR));monthleft.setForeground(Color.BLACK);}public void mousePressed(MouseEvent me) {select.add(Calendar.MONTH, -1);monthleft.setForeground(Color.WHITE);refresh();}public void mouseReleased(MouseEvent me) {monthleft.setForeground(Color.BLACK);}});monthright.addMouseListener(new MouseAdapter() {public void mouseEntered(MouseEvent me) {monthright.setCursor(new Cursor(Cursor.HAND_CURSOR));monthright.setForeground(Color.RED);}public void mouseExited(MouseEvent me) {monthright.setCursor(new Cursor(Cursor.DEFAULT_CURSOR));monthright.setForeground(Color.BLACK);}public void mousePressed(MouseEvent me) {select.add(Calendar.MONTH, 1);monthright.setForeground(Color.WHITE);refresh();}public void mouseReleased(MouseEvent me) {monthright.setForeground(Color.BLACK);}});}private void updateDate() {center.setText(select.get(Calendar.YEAR) + "年"+ (select.get(Calendar.MONTH) + 1) + "月");}}private class JP2 extends JPanel {private static final long serialVersionUID = -8176264838786175724L;public JP2() {this.setPreferredSize(new Dimension(295, 20));}protected void paintComponent(Graphics g) {g.setFont(font);g.drawString("星期日 星期一 星期二 星期三 星期四 星期五 星期六", 5, 10);g.drawLine(0, 15, getWidth(), 15);}private void updateDate() {}}private class JP3 extends JPanel {private static final long serialVersionUID = 43157272447522985L;public JP3() {super(new GridLayout(6, 7));this.setPreferredSize(new Dimension(295, 100));initJP3();}private void initJP3() {updateDate();}public void updateDate() {this.removeAll();lm.clear();Date temp = select.getTime();Calendar select = Calendar.getInstance();select.setTime(temp);select.set(Calendar.DAY_OF_MONTH, 1);int index = select.get(Calendar.DAY_OF_WEEK);int sum = (index == 1 ? 8 : index);select.add(Calendar.DAY_OF_MONTH, 0 - sum);for (int i = 0; i < 42; i++) {select.add(Calendar.DAY_OF_MONTH, 1);lm.addLabel(new MyLabel(select.get(Calendar.YEAR), select.get(Calendar.MONTH), select.get(Calendar.DAY_OF_MONTH)));}for (MyLabel my : lm.getLabels()) {this.add(my);}select.setTime(temp);}}private class MyLabel extends JLabel implements Comparator<MyLabel>,MouseListener, MouseMotionListener {private static final long serialVersionUID = 3668734399227577214L;private int year, month, day;private boolean isSelected;public MyLabel(int year, int month, int day) {super("" + day, JLabel.CENTER);this.year = year;this.day = day;this.month = month;this.addMouseListener(this);this.addMouseMotionListener(this);this.setFont(font);if (month == select.get(Calendar.MONTH)) {this.setForeground(Color.BLACK);} else {this.setForeground(Color.LIGHT_GRAY);}if (day == select.get(Calendar.DAY_OF_MONTH)) {this.setBackground(new Color(160, 185, 215));} else {this.setBackground(Color.WHITE);}}public boolean getIsSelected() {return isSelected;}public void setSelected(boolean b, boolean isDrag) {isSelected = b;if (b && !isDrag) {int temp = select.get(Calendar.MONTH);select.set(year, month, day);if (temp == month) {SwingUtilities.updateComponentTreeUI(jp3);} else {refresh();}}this.repaint();}protected void paintComponent(Graphics g) {if (day == select.get(Calendar.DAY_OF_MONTH)&& month == select.get(Calendar.MONTH)) {// 如果当前日期是选择日期,则高亮显示g.setColor(new Color(160, 185, 215));g.fillRect(0, 0, getWidth(), getHeight());}if (year == now.get(Calendar.YEAR)&& month == now.get(Calendar.MONTH)&& day == now.get(Calendar.DAY_OF_MONTH)) {// 如果日期和当前日期一样,则用红框Graphics2D gd = (Graphics2D) g;gd.setColor(Color.RED);Polygon p = new Polygon();p.addPoint(0, 0);p.addPoint(getWidth() - 1, 0);p.addPoint(getWidth() - 1, getHeight() - 1);p.addPoint(0, getHeight() - 1);gd.drawPolygon(p);}if (isSelected) {// 如果被选中了就画出一个虚线框出来Stroke s = new BasicStroke(1.0f, BasicStroke.CAP_SQUARE,BasicStroke.JOIN_BEVEL, 1.0f,new float[]{2.0f, 2.0f}, 1.0f);Graphics2D gd = (Graphics2D) g;gd.setStroke(s);gd.setColor(Color.BLACK);Polygon p = new Polygon();p.addPoint(0, 0);p.addPoint(getWidth() - 1, 0);p.addPoint(getWidth() - 1, getHeight() - 1);p.addPoint(0, getHeight() - 1);gd.drawPolygon(p);}super.paintComponent(g);}public boolean contains(Point p) {return this.getBounds().contains(p);}private void update() {repaint();}public void mouseClicked(MouseEvent e) {}public void mousePressed(MouseEvent e) {isSelected = true;update();}public void mouseReleased(MouseEvent e) {Point p = SwingUtilities.convertPoint(this, e.getPoint(), jp3);lm.setSelect(p, false);commit();}public void mouseEntered(MouseEvent e) {}public void mouseExited(MouseEvent e) {}public void mouseDragged(MouseEvent e) {Point p = SwingUtilities.convertPoint(this, e.getPoint(), jp3);lm.setSelect(p, true);}public void mouseMoved(MouseEvent e) {}public int compare(MyLabel o1, MyLabel o2) {Calendar c1 = Calendar.getInstance();c1.set(o1.year, o2.month, o1.day);Calendar c2 = Calendar.getInstance();c2.set(o2.year, o2.month, o2.day);return c1.compareTo(c2);}}private class LabelManager {private List<MyLabel> list;public LabelManager() {list = new ArrayList<MyLabel>();}public List<MyLabel> getLabels() {return list;}public void addLabel(MyLabel my) {list.add(my);}public void clear() {list.clear();}@SuppressWarnings("unused")public void setSelect(MyLabel my, boolean b) {for (MyLabel m : list) {if (m.equals(my)) {m.setSelected(true, b);} else {m.setSelected(false, b);}}}public void setSelect(Point p, boolean b) {// 如果是拖动,则要优化一下,以提高效率if (b) {// 表示是否能返回,不用比较完所有的标签,能返回的标志就是把上一个标签和// 将要显示的标签找到了就可以了boolean findPrevious = false, findNext = false;for (MyLabel m : list) {if (m.contains(p)) {findNext = true;if (m.getIsSelected()) {findPrevious = true;} else {m.setSelected(true, b);}} else if (m.getIsSelected()) {findPrevious = true;m.setSelected(false, b);}if (findPrevious && findNext) {return;}}} else {MyLabel temp = null;for (MyLabel m : list) {if (m.contains(p)) {temp = m;} else if (m.getIsSelected()) {m.setSelected(false, b);}}if (temp != null) {temp.setSelected(true, b);}}}}private class JP4 extends JPanel {private static final long serialVersionUID = -6391305687575714469L;public JP4() {super(new BorderLayout());this.setPreferredSize(new Dimension(295, 20));this.setBackground(new Color(160, 185, 215));SimpleDateFormat sdf = new SimpleDateFormat("yyyy年MM月dd日");final JLabel jl = new JLabel("今天: " + sdf.format(new Date()));jl.setToolTipText("点击选择今天日期");this.add(jl, BorderLayout.CENTER);jl.addMouseListener(new MouseAdapter() {public void mouseEntered(MouseEvent me) {jl.setCursor(new Cursor(Cursor.HAND_CURSOR));jl.setForeground(Color.RED);}public void mouseExited(MouseEvent me) {jl.setCursor(new Cursor(Cursor.DEFAULT_CURSOR));jl.setForeground(Color.BLACK);}public void mousePressed(MouseEvent me) {jl.setForeground(Color.WHITE);select.setTime(new Date());refresh();commit();}public void mouseReleased(MouseEvent me) {jl.setForeground(Color.BLACK);}});}private void updateDate() {}}
}

 public class AttendanceQuery02 {public static void main(String[] args) {//1.创建窗体对象JFrame jf = new JFrame();jf.setTitle("考勤查询");jf.setSize(400, 300);jf.setDefaultCloseOperation(3);jf.setLocationRelativeTo(null);jf.setAlwaysOnTop(true);jf.setLayout(null);//2.显示考勤日期的文本JLabel dateLable = new JLabel("考勤日期");dateLable.setBounds(50,20,100,20);jf.add(dateLable);//3.显示开始时间文本JLabel startDateLable = new JLabel("开始时间");startDateLable.setBounds(50,70,100,20);jf.add(startDateLable);//4.创建日历控件DateChooser dateChooser1 = DateChooser.getInstance("yyyy/MM/dd");DateChooser dateChooser2 = DateChooser.getInstance("yyyy/MM/dd");//5.开始时间输入框JTextField startDateField = new JTextField();startDateField.setBounds(50,100,100,20);dateChooser1.register(startDateField); //日历控件绑定到，开始时间输入框中jf.add(startDateField);//6.显示结束时间文本JLabel endDateLable = new JLabel("结束时间");endDateLable.setBounds(250,70,100,20);jf.add(endDateLable);//7.结束时间输入框JTextField endDateField = new JTextField();endDateField.setBounds(250,100,100,20);dateChooser2.register(endDateField); //日历控件绑定到，结束时间输入框中jf.add(endDateField);//8.确定按钮JButton confirmButton = new JButton("确定");confirmButton.setBounds(250,180,60,20);jf.add(confirmButton);//9.设置窗体可见jf.setVisible(true);}}

(10)事件监听机制
10.1.事件监听机制概述
事件源： 事件发生的地方。可以是按钮，窗体，图片等;
事件： 发生了什么事情。例如：鼠标点击事件，键盘按下事件等;
事件绑定： 把事件绑定到事件源上，当发生了某个事件，则触发对应的处理逻辑;
事件源对象. addXXXListener(事件);
10.2 事件监听机制案例

 public class ActionListenerDemo {public static void main(String[] args) {//1.创建窗体对象JFrame jf = new JFrame();jf.setTitle("事件监听机制");jf.setSize(400, 300);jf.setDefaultCloseOperation(3);jf.setLocationRelativeTo(null);jf.setAlwaysOnTop(true);jf.setLayout(null);//2.创建按钮JButton jButton = new JButton("你点我啊");jButton.setBounds(0, 0, 100, 100);jf.add(jButton);//3.给按钮绑定事件jButton.addActionListener(new ActionListener() {@Overridepublic void actionPerformed(ActionEvent e) {System.out.println("你点我啊"); //事件触发执行逻辑}});//4.设置窗体可见jf.setVisible(true);}}