在界面底端放置符合窗口大小的缩略图，原图较大！求代码！
Java codeimport java.sql.*;import java.awt.*;import java.awt.event.*;import javax.swing.*;import java.io.*;public class UpdateDemo extends JFrame { // public class UpdateDemo{ private String dbURL = "jdbc:mysql://localhost/book?useUnicode=true&characterEncoding=GBK"; // 数据库标识名 private String user = "root"; // 数据库用户 private String password = ""; // 数据库用户密码 public UpdateDemo() { super("添加一本书"); // 调用父类构造函数 final Frame f=new Frame("添加一本书"); Container container = getContentPane(); // 得到容器 final JTextField jtf = new JTextField(18); // 实例化地址输入框 //jtf.setBounds(18, 20, 153, 25); final JTextField jtf1 = new JTextField(18); final JTextField jtf2 = new JTextField(18); final JTextField jtf3 = new JTextField(18); final JTextField jtf4 = new JTextField(18); final JTextField jtf5 = new JTextField(18); final JTextField jtf6 = new JTextField(18); final JTextField jtf7 = new JTextField(18); final JButton jb1 = new JButton("确定"); // 实例化按钮 final JButton jb2 = new JButton("浏览..."); JLabel jl = new JLabel("书 名："); JLabel jl1 = new JLabel("副标题："); JLabel jl2 = new JLabel("作 者："); JLabel jl3 = new JLabel("国 籍："); JLabel jl4 = new JLabel("出版社："); JLabel jl5 = new JLabel("价 格："); JLabel jl6 = new JLabel("I S B N ："); JLabel jl7 = new JLabel("封 面："); container.setLayout(new FlowLayout()); // 设置布局管理器 container.add(jl); // 增加组件到容器上 container.add(jtf); container.add(jl1); container.add(jtf1); container.add(jl2); container.add(jtf2); container.add(jl3); container.add(jtf3); container.add(jl4); container.add(jtf4); container.add(jl5); container.add(jtf5); container.add(jl6); container.add(jtf6); container.add(jl7); container.add(jtf7); container.add(jb2); // container.add(jtfUrl1); container.add(jb1); setSize(300, 768); // 设置窗口尺寸 //距离左上角图标距离100,100 setLocation(0,0); //设置主键排列方式为靠左 setLayout(new FlowLayout(FlowLayout.LEFT)); //设置主键排列方式为3行2列,水平、垂直间隙为10 //setLayout(new GridLayout(8,2,10,10)); setVisible(true); // 设置窗口可视 setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); // 关闭窗口时退出程序 jb2.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent ent) { try { FileDialog fd=new FileDialog(f,"open file", FileDialog.LOAD); fd.setVisible(true);//替代fd.show(); String strFile=fd.getDirectory()+fd.getFile(); ImageIcon icon = new ImageIcon(strFile); JLabel jlb = new JLabel(); scaleImage(icon); jlb.setIcon(icon); // 将图片加入 String Str7=fd.getDirectory()+fd.getFile();//取得文件完整路径 //System.out.println(Str7); jtf7.setText(fd.getFile()); //f.add(jlb); add(jlb); jlb.setSize(250, 300); //jlb.setBounds(0,200,100,200);//设置坐标x，y；宽度，高度 jlb.setLocation(0,250); jlb.setVisible(true);//替代jlb.show(); }catch (Exception ex) { ex.printStackTrace(); // 输出出错信息 } } }); jb1.addActionListener(new ActionListener() { // 按钮事件处理 public void actionPerformed(ActionEvent ent) { try { String Str = jtf.getText(); // 得到图像的URL地址 String Str1 = jtf1.getText(); String Str2 = jtf2.getText(); String Str3 = jtf3.getText(); String Str4 = jtf4.getText(); String Str5 = jtf5.getText(); String Str6 = jtf6.getText(); String Str7= jtf7.getText(); System.out.println(Str7); // System.out.println(Str1); method(Str,Str1,Str2,Str3,Str4,Str5,Str6,Str7); } catch (Exception ex) { ex.printStackTrace(); // 输出出错信息 } } }); } private ImageIcon scaleImage(ImageIcon icon) { int width = icon.getIconWidth(); //System.out.print(width); int height = icon.getIconHeight(); if (width <= 80 && height <= 80) { return icon; } Image image = icon.getImage(); image = image.getScaledInstance(80, 80, Image.SCALE_DEFAULT); return new ImageIcon(image); } public void method(String str,String str1,String str2,String str3,String str4,String str5,String str6,String str7){ try { Class.forName("com.mysql.jdbc.Driver"); // 加载驱动器 Connection con = DriverManager.getConnection(dbURL, user, password); // 获取连接 String sqlStr = "select * from user"; // SQL查询语句 Statement st = con.createStatement(); // 获取PreparedStatement对象 ResultSet rs = st.executeQuery(sqlStr); // 执行查询 String id, title, subhead, authors, nationality, publisher, price, isbn; // 查询结果 // int age; System.err.println("更新前数据"); while (rs.next()) { // 遍历ResultSet id = rs.getString("id"); // 获取数据 title = rs.getString("title"); subhead = rs.getString("subhead"); authors = rs.getString("authors"); nationality = rs.getString("nationality"); publisher = rs.getString("publisher"); price = rs.getString("price"); isbn = rs.getString("isbn"); /* * System.out.println("id: "+id+"\ttitle:"+title+"\tsubhead:"+subhead * +"\tauthors:"+authors+"\t nationality:"+nationality * +"\tpublisher:"+publisher+"\tprice"+price+"\t isbn"+isbn); * //在控制台输出数据 * /*JOptionPane.showMessageDialog(null,"序号: "+id+"\n书名:" * +title+"\n副标题:"+subhead+"\n作者:"+authors+"\n国籍:"+nationality * +"\n出版社:"+publisher+"\n价格"+price+"\nISBN"+isbn); */ } // 插入操作 //st.executeUpdate("insert into user values(4, '维基经济学', '大规模协作如何改变一切', '唐·泰普斯科特', '加拿大', '中国青年出版社', '30.00', '9787500676911')"); sqlStr="insert into user(title,subhead,authors,nationality,publisher,price,isbn,url) values('"+str+"','"+str1+"','"+str2+"','"+str3+"','"+str4+"','"+str5+"','"+str6+"','"+str7+"')"; st.executeUpdate(sqlStr); // 更新操作 // sqlStr="update user set age=21 where id=\'2\'"; // st.executeUpdate(sqlStr); // 删除操作 // sqlStr="delete from user where name=\'Jinnifier\'"; // st.executeUpdate(sqlStr); // 显示修改后结果 System.err.println("更新后数据"); sqlStr = "select * from user"; // SQL查询语句 rs = st.executeQuery(sqlStr); // 执行查询 while (rs.next()) { // 遍历ResultSet id = rs.getString("id"); // 获取数据 title = rs.getString("title"); subhead = rs.getString("subhead"); authors = rs.getString("authors"); nationality = rs.getString("nationality"); publisher = rs.getString("publisher"); price = rs.getString("price"); isbn = rs.getString("isbn"); /* * System.out.println("id: "+id+"\ttitle:"+title+"\tsubhead:"+subhead * +"\tauthors:"+authors+"\t nationality:"+nationality * +"\tpublisher:"+publisher+"\tprice"+price+"\t isbn"+isbn); * //在控制台输出数据 * JOptionPane.showMessageDialog(null,"序号: "+id+"\t书名:" * +title+"\t副标题:"+subhead+"\t作者:"+authors+"\t 国籍:"+nationality * +"\t出版社:"+publisher+"\t价格"+price+"\t ISBN"+isbn); */ } con.close(); // 关闭连接 } catch (Exception ex) { ex.printStackTrace(); // 输出出错信息 } } public static void main(String[] args) { new UpdateDemo(); }}