java图形界面里面怎么实现图片缩放，比如我有一个frame里面放了一个label，label上面有张图片，当frame大小改变时让图片一起变，图片原来是将label填满的，
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稍后贴代码
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Image image = new ImageIcon("images/set2.jpg").getImage();
image = image.getScaledInstance(300, 180, 0);
JLabel label = new JLabel();
label.setBounds(70, 75, 300, 200);
label.setIcon(new ImageIcon(image));
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- Java code
package musicPlatform.client.login;import java.awt.*;import javax.swing.*;import musicPlatform.client.config.SaveMusicFileDirectory;import testSwing2.UsedToChangeMyFrame;public class SubstituteLoginFrame extends JFrame { private static final long serialVersionUID = 2022587044957057382L; private JButton jButton1;// 登录 private JButton jButton2;// 注册 private JLabel jLabel2;// 密码 private JPasswordField jTextField2;// 密码 private JTextField jTextField1;// 用户名 private JLabel jLabel1;// 用户名 public static void main(String[] args) { SwingUtilities.invokeLater(new Runnable() { public void run() { new SubstituteLoginFrame(); } }); } private static void clientConfig() { String defaultPath = System.getProperty("user.home") + "\\" + "music"; SaveMusicFileDirectory save = new SaveMusicFileDirectory(); save.creatXML(defaultPath); } public SubstituteLoginFrame() { super(); autoTest();// 检查服务器 init(); } /** * 首次开启客户端时检查连接状态 */ private void autoTest() { RespondLoginEnter res = new RespondLoginEnter(); res.initialTestLinkage(); } public void illegalCallingEntrance() { SubstituteLoginFrame lf = new SubstituteLoginFrame(); lf.setLocationRelativeTo(null); lf.setVisible(true); } public void init() { Container c = this.getContentPane(); JPanel lowerPanel = new MyPanelk(); c.add(lowerPanel); GroupLayout lowerPanelLayout = new GroupLayout((JComponent) lowerPanel); lowerPanel.setLayout(lowerPanelLayout); lowerPanel.setLocale(new java.util.Locale("zh", "TW")); // lowerPanel.setPreferredSize(new Dimension(1100, 680)); { jButton1 = new JButton(); jButton1.setText("注册"); } { jButton2 = new JButton(); jButton2.setText("\u767b\u5f55"); } { jLabel1 = new JLabel(); jLabel1.setText("\u7528\u6237\u540d"); jLabel1.setFont(new java.awt.Font("微软雅黑", 3, 11)); jLabel1.setForeground(new java.awt.Color(255, 255, 255)); } { jLabel2 = new JLabel(); jLabel2.setText("\u5bc6\u7801"); jLabel2.setFont(new java.awt.Font("微软雅黑", 3, 11)); jLabel2.setForeground(new java.awt.Color(255, 255, 255)); } { jTextField2 = new JPasswordField(); jTextField2.addFocusListener(new FocusAdapter() { public void focusGained(FocusEvent evt) { jTextField2.selectAll(); } }); } { jTextField1 = new JTextField(); jTextField1.addFocusListener(new FocusAdapter() { public void focusGained(FocusEvent evt) { jTextField1.selectAll(); } }); } lowerPanelLayout.setVerticalGroup(lowerPanelLayout .createSequentialGroup() .addContainerGap(63, 63) .addGroup( lowerPanelLayout .createParallelGroup( GroupLayout.Alignment.BASELINE) .addComponent(jTextField1, GroupLayout.Alignment.BASELINE, GroupLayout.PREFERRED_SIZE, 21, GroupLayout.PREFERRED_SIZE) .addComponent(jLabel1, GroupLayout.Alignment.BASELINE, GroupLayout.PREFERRED_SIZE, GroupLayout.PREFERRED_SIZE, GroupLayout.PREFERRED_SIZE)) .addGap(19) .addGroup( lowerPanelLayout .createParallelGroup( GroupLayout.Alignment.BASELINE) .addComponent(jTextField2, GroupLayout.Alignment.BASELINE, GroupLayout.PREFERRED_SIZE, 21, GroupLayout.PREFERRED_SIZE) .addComponent(jLabel2, GroupLayout.Alignment.BASELINE, GroupLayout.PREFERRED_SIZE, GroupLayout.PREFERRED_SIZE, GroupLayout.PREFERRED_SIZE)) .addGap(29) .addGroup( lowerPanelLayout .createParallelGroup( GroupLayout.Alignment.BASELINE) .addComponent(jButton2, GroupLayout.Alignment.BASELINE, GroupLayout.PREFERRED_SIZE, 22, GroupLayout.PREFERRED_SIZE) .addComponent(jButton1, GroupLayout.Alignment.BASELINE, GroupLayout.PREFERRED_SIZE, 22, GroupLayout.PREFERRED_SIZE)) .addContainerGap(45, 45)); lowerPanelLayout .setHorizontalGroup(lowerPanelLayout .createSequentialGroup() .addContainerGap(108, 108) .addGroup( lowerPanelLayout .createParallelGroup() .addGroup( lowerPanelLayout .createSequentialGroup() .addGroup( lowerPanelLayout .createParallelGroup() .addComponent( jLabel1, GroupLayout.Alignment.LEADING, GroupLayout.PREFERRED_SIZE, 46, GroupLayout.PREFERRED_SIZE) .addGroup( GroupLayout.Alignment.LEADING, lowerPanelLayout .createSequentialGroup() .addComponent( jLabel2, GroupLayout.PREFERRED_SIZE, 26, GroupLayout.PREFERRED_SIZE) .addGap(20))) .addPreferredGap( LayoutStyle.ComponentPlacement.RELATED, 12, Short.MAX_VALUE) .addGroup( lowerPanelLayout .createParallelGroup() .addComponent( jTextField2, GroupLayout.Alignment.LEADING, GroupLayout.PREFERRED_SIZE, 108, GroupLayout.PREFERRED_SIZE) .addComponent( jTextField1, GroupLayout.Alignment.LEADING, GroupLayout.PREFERRED_SIZE, 108, GroupLayout.PREFERRED_SIZE))) .addGroup( GroupLayout.Alignment.LEADING, lowerPanelLayout .createSequentialGroup() .addPreferredGap( jLabel2, jButton1, LayoutStyle.ComponentPlacement.INDENT) .addComponent(jButton1, 0, 67, Short.MAX_VALUE) .addGap(17) .addComponent( jButton2, GroupLayout.PREFERRED_SIZE, 70, GroupLayout.PREFERRED_SIZE))) .addContainerGap(120, 120)); /** * 注册监听 */ { jButton1.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent evt) { // lf.setVisible(false); // System.out.println("这里可以显示注册窗口了"); SubstituteLoginFrame.this.setVisible(false); // SubstituteLoginFrame.this.dispose(); RespondLoginEnter res = new RespondLoginEnter(); res.testLinkage(); new LogonJFrame(); InOn inon = new InOn();// 保存本登录窗口对象 inon.backToLogin(SubstituteLoginFrame.this); } }); } /** * 登录监听 */ { // jButton1.addActionListener(new // jButton1ActionListener(this)); jButton2.addActionListener(new ActionListener() { // 注册按钮事件 public void actionPerformed(ActionEvent event) { // 事件处理器 String userName = jTextField1.getText(); String password = jTextField2.getText(); // 检查输入合法性 if (ToolString.isInefficacy(userName) || ToolString.isInefficacy(password)) { JOptionPane.showMessageDialog(null, " 用户名和密码不能为空", "请重新输入", JOptionPane.ERROR_MESSAGE); return; } RespondLoginEnter respondLogin = new RespondLoginEnter(); try { // 连接服务器 respondLogin.linkage(); // 包装用户名，密码:request=login★userName=a★userPassword=d★ String nameAndPass = ToolString.packageLoginData( userName, password); // 发送用户名，密码 respondLogin.sendMessage(nameAndPass);// 发送成功后客户端若等不到服务器数据，界面不响应 // 获得服务器响应 收不到数据的处理？ System.out .println("开始接收服务器数据：loginsuccess or loginfail！"); String receivedMsg = respondLogin.receiveMsg(); if (receivedMsg == null) { System.out.println("服务器响应超时！");// 能否显示？？？？？？？？？？？？？？？？？ } // respondLogin.close(); // // 需要关闭????????????登錄成功也會關閉???????????????????????????? if (!"loginsuccess".equals(receivedMsg)) { JOptionPane.showMessageDialog(null, "用户名或密码错误", "登录失败", JOptionPane.ERROR_MESSAGE); return; } else { // System.out.println("这里开始显示主页并关闭登录窗口");// // ------------------------------------------------------- SubstituteLoginFrame.this.dispose(); // 登录成功， 显示主页窗口 new UsedToChangeMyFrame(); } } catch (Exception e) { e.printStackTrace(); } } }); } this.setVisible(true); this.setResizable(false); String direct = System.getProperty("user.dir") + "\\src\\icon\\pro\\key1.gif"; Image img = Toolkit.getDefaultToolkit().getImage(direct); this.setIconImage(img); Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize(); this.setLocation(screenSize.width / 2 - 400 / 2, screenSize.height / 2 - 250 / 2); this.setTitle("\u97f3\u4e50\u5e73\u53f0"); // this.setSize(new Dimension(1100, 680)); this.setSize(new Dimension(400, 250)); }}class MyPanelk extends JPanel { /** * */ private static final long serialVersionUID = 1L; @Override public void paintComponent(Graphics g) { // 重绘函数 Graphics2D g2 = (Graphics2D) g; super.paintComponent(g); String directory = System.getProperty("user.dir") + "\\src\\icon\\pro\\wow2.jpg"; Image img = Toolkit.getDefaultToolkit().getImage(directory); g2.drawImage(img, 0, 0, this.getWidth(), this.getHeight(), this); // 在面板上绘制背景图片 }}
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Image的getScaledINnstance(int width, int height, int hints)方法
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- Java code