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我正在构建一个 JAVA Netbeans 和 MySQL 程序，用户可以在其中将图像插入和更新到数据库中。它被成功插入。我已将这些图像设置为显示在 Jlabel 中。但是，一旦我更新了该图像，它就会更新，但图像不会显示在 Jlabel 中。请帮我解决这个问题。这是我的代码

package Frames;
import Methods.DB_Con;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.sql.*;
import javax.swing.*;
import net.proteanit.sql.DbUtils;



public class EditCategory extends javax.swing.JFrame {
    private ImageIcon format=null;
    String filename = null;
     int s = 0;
     byte[] category_image = null;

    public void Update_Table(){
        try{
              ResultSet rs;
              Connection con = DB_Con.getConnection();
              String sql ="select Category_Code,Category_Name from category";
              PreparedStatement st = (PreparedStatement) con.prepareStatement(sql);
              rs=st.executeQuery();
              jTable1.setModel(DbUtils.resultSetToTableModel(rs));




              st.close();
        }
        catch(Exception e){
            JOptionPane.showMessageDialog(null, "Error loading table");
        }
    }

    public void set_Icon(){

        try{
           int row= jTable1.getSelectedRow();
           jLabel4.setText(jTable1.getModel().getValueAt(row, 0).toString());
           jTextField1.setText(jTable1.getModel().getValueAt(row, 1).toString());
           Connection con = DB_Con.getConnection();
           ResultSet rs;
           String cat_id=jTable1.getModel().getValueAt(row, 0).toString();

           String sql ="select Category_Image from category where Category_Code='"+cat_id+"'";
           PreparedStatement st = (PreparedStatement) con.prepareStatement(sql);
           rs = st.executeQuery();

           if(rs.next()){
               byte[] imagedata=rs.getBytes("Category_Image");
               format =new ImageIcon(imagedata);
               jLabel1.setIcon(format);
           }
         }
         catch(Exception e){
         }
    }

    /** Creates new form EditCategory */
    public EditCategory() {
        initComponents();



    }


    /** This method is called from within the constructor to
     * initialize the form.
     * WARNING: Do NOT modify this code. The content of this method is
     * always regenerated by the Form Editor.
     */
    @SuppressWarnings("unchecked")
    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {

        jLabel12 = new javax.swing.JLabel();
        jScrollPane1 = new javax.swing.JScrollPane();
        jTable1 = new javax.swing.JTable();
        jButton2 = new javax.swing.JButton();
        jButton3 = new javax.swing.JButton();
        jLabel5 = new javax.swing.JLabel();
        jLabel1 = new javax.swing.JLabel();
        jPanel1 = new javax.swing.JPanel();
        jLabel4 = new javax.swing.JLabel();
        jLabel2 = new javax.swing.JLabel();
        jButton1 = new javax.swing.JButton();
        jTextField2 = new javax.swing.JTextField();
        jLabel3 = new javax.swing.JLabel();
        jTextField1 = new javax.swing.JTextField();

        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        addWindowFocusListener(new java.awt.event.WindowFocusListener() {
            public void windowGainedFocus(java.awt.event.WindowEvent evt) {
                formWindowGainedFocus(evt);
            }
            public void windowLostFocus(java.awt.event.WindowEvent evt) {
            }
        });
        addWindowListener(new java.awt.event.WindowAdapter() {
            public void windowOpened(java.awt.event.WindowEvent evt) {
                formWindowOpened(evt);
            }
        });

        jLabel12.setBackground(new java.awt.Color(255, 255, 255));
        jLabel12.setFont(new java.awt.Font("Tahoma", 0, 36));
        jLabel12.setForeground(new java.awt.Color(255, 0, 0));
        jLabel12.setHorizontalAlignment(javax.swing.SwingConstants.CENTER);
        jLabel12.setText("Edit Category");
        jLabel12.setBorder(javax.swing.BorderFactory.createBevelBorder(javax.swing.border.BevelBorder.RAISED, null, new java.awt.Color(0, 153, 255), null, null));

        jTable1.setBackground(new java.awt.Color(204, 204, 255));
        jTable1.setModel(new javax.swing.table.DefaultTableModel(
            new Object [][] {

            },
            new String [] {
                "", ""
            }
        ) {
            Class[] types = new Class [] {
                java.lang.Integer.class, java.lang.Object.class
            };
            boolean[] canEdit = new boolean [] {
                false, false
            };

            public Class getColumnClass(int columnIndex) {
                return types [columnIndex];
            }

            public boolean isCellEditable(int rowIndex, int columnIndex) {
                return canEdit [columnIndex];
            }
        });
        jTable1.addMouseListener(new java.awt.event.MouseAdapter() {
            public void mouseClicked(java.awt.event.MouseEvent evt) {
                jTable1MouseClicked(evt);
            }
        });
        jScrollPane1.setViewportView(jTable1);
        jTable1.getColumnModel().getColumn(0).setResizable(false);
        jTable1.getColumnModel().getColumn(1).setResizable(false);

        jButton2.setText("Done");
        jButton2.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton2ActionPerformed(evt);
            }
        });

        jButton3.setText("Back");
        jButton3.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton3ActionPerformed(evt);
            }
        });

        jLabel5.setHorizontalAlignment(javax.swing.SwingConstants.CENTER);
        jLabel5.setText("**Click on table row to get values to edit**");
        jLabel5.setBorder(javax.swing.BorderFactory.createBevelBorder(javax.swing.border.BevelBorder.RAISED, null, new java.awt.Color(0, 153, 255), null, null));

        jLabel1.setBackground(new java.awt.Color(204, 255, 204));
        jLabel1.setHorizontalAlignment(javax.swing.SwingConstants.CENTER);
        jLabel1.setBorder(javax.swing.BorderFactory.createBevelBorder(javax.swing.border.BevelBorder.RAISED));

        jPanel1.setBackground(new java.awt.Color(204, 204, 204));
        jPanel1.setBorder(javax.swing.BorderFactory.createBevelBorder(javax.swing.border.BevelBorder.RAISED));

        jLabel4.setHorizontalAlignment(javax.swing.SwingConstants.CENTER);
        jLabel4.setBorder(javax.swing.BorderFactory.createBevelBorder(javax.swing.border.BevelBorder.RAISED));

        jLabel2.setHorizontalAlignment(javax.swing.SwingConstants.CENTER);
        jLabel2.setText("Edit Category Name");
        jLabel2.setBorder(javax.swing.BorderFactory.createEtchedBorder());

        jButton1.setText("Browse New Image");
        jButton1.addActionListener(new java.awt.event.ActionListener() {
            public void actionPerformed(java.awt.event.ActionEvent evt) {
                jButton1ActionPerformed(evt);
            }
        });

        jLabel3.setHorizontalAlignment(javax.swing.SwingConstants.CENTER);
        jLabel3.setText("Category Code");
        jLabel3.setBorder(javax.swing.BorderFactory.createEtchedBorder());

        jTextField1.setHorizontalAlignment(javax.swing.JTextField.CENTER);

        javax.swing.GroupLayout jPanel1Layout = new javax.swing.GroupLayout(jPanel1);
        jPanel1.setLayout(jPanel1Layout);
        jPanel1Layout.setHorizontalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addGroup(jPanel1Layout.createSequentialGroup()
                        .addComponent(jButton1, javax.swing.GroupLayout.PREFERRED_SIZE, 150, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(100, 100, 100)
                        .addComponent(jTextField2, javax.swing.GroupLayout.PREFERRED_SIZE, 440, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addGroup(jPanel1Layout.createSequentialGroup()
                        .addGap(10, 10, 10)
                        .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING, false)
                            .addComponent(jLabel3, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
                            .addComponent(jLabel2, javax.swing.GroupLayout.Alignment.TRAILING, javax.swing.GroupLayout.DEFAULT_SIZE, 128, Short.MAX_VALUE))
                        .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                            .addGroup(jPanel1Layout.createSequentialGroup()
                                .addGap(112, 112, 112)
                                .addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, 440, javax.swing.GroupLayout.PREFERRED_SIZE))
                            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, jPanel1Layout.createSequentialGroup()
                                .addGap(112, 112, 112)
                                .addComponent(jLabel4, javax.swing.GroupLayout.PREFERRED_SIZE, 440, javax.swing.GroupLayout.PREFERRED_SIZE)))))
                .addContainerGap())
        );
        jPanel1Layout.setVerticalGroup(
            jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(jPanel1Layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jLabel4, javax.swing.GroupLayout.PREFERRED_SIZE, 20, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jLabel3, javax.swing.GroupLayout.PREFERRED_SIZE, 20, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(16, 16, 16)
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jLabel2, javax.swing.GroupLayout.PREFERRED_SIZE, 22, javax.swing.GroupLayout.PREFERRED_SIZE)
                    .addComponent(jTextField1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(28, 28, 28)
                .addGroup(jPanel1Layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
                    .addComponent(jButton1)
                    .addComponent(jTextField2, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addContainerGap())
        );

        javax.swing.GroupLayout layout = new javax.swing.GroupLayout(getContentPane());
        getContentPane().setLayout(layout);
        layout.setHorizontalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addGap(195, 195, 195)
                .addComponent(jButton2, javax.swing.GroupLayout.PREFERRED_SIZE, 109, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(209, 209, 209)
                .addComponent(jButton3, javax.swing.GroupLayout.PREFERRED_SIZE, 76, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(218, 218, 218))
            .addGroup(layout.createSequentialGroup()
                .addGap(61, 61, 61)
                .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 437, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addPreferredGap(javax.swing.LayoutStyle.ComponentPlacement.RELATED, 115, Short.MAX_VALUE)
                .addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 140, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(87, 87, 87))
            .addGroup(javax.swing.GroupLayout.Alignment.TRAILING, layout.createSequentialGroup()
                .addContainerGap(288, Short.MAX_VALUE)
                .addComponent(jLabel12, javax.swing.GroupLayout.PREFERRED_SIZE, 280, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(272, 272, 272))
            .addGroup(layout.createSequentialGroup()
                .addGap(160, 160, 160)
                .addComponent(jLabel5, javax.swing.GroupLayout.PREFERRED_SIZE, 246, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(434, Short.MAX_VALUE))
            .addGroup(layout.createSequentialGroup()
                .addGap(28, 28, 28)
                .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addContainerGap(98, Short.MAX_VALUE))
        );

        layout.linkSize(javax.swing.SwingConstants.HORIZONTAL, new java.awt.Component[] {jButton2, jButton3});

        layout.setVerticalGroup(
            layout.createParallelGroup(javax.swing.GroupLayout.Alignment.LEADING)
            .addGroup(layout.createSequentialGroup()
                .addContainerGap()
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.TRAILING)
                    .addGroup(layout.createSequentialGroup()
                        .addComponent(jLabel12, javax.swing.GroupLayout.PREFERRED_SIZE, 60, javax.swing.GroupLayout.PREFERRED_SIZE)
                        .addGap(18, 18, 18)
                        .addComponent(jScrollPane1, javax.swing.GroupLayout.PREFERRED_SIZE, 138, javax.swing.GroupLayout.PREFERRED_SIZE))
                    .addComponent(jLabel1, javax.swing.GroupLayout.PREFERRED_SIZE, 120, javax.swing.GroupLayout.PREFERRED_SIZE))
                .addGap(33, 33, 33)
                .addComponent(jLabel5, javax.swing.GroupLayout.PREFERRED_SIZE, 30, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(29, 29, 29)
                .addComponent(jPanel1, javax.swing.GroupLayout.PREFERRED_SIZE, javax.swing.GroupLayout.DEFAULT_SIZE, javax.swing.GroupLayout.PREFERRED_SIZE)
                .addGap(37, 37, 37)
                .addGroup(layout.createParallelGroup(javax.swing.GroupLayout.Alignment.BASELINE)
                    .addComponent(jButton2)
                    .addComponent(jButton3))
                .addContainerGap(41, Short.MAX_VALUE))
        );

        java.awt.Dimension screenSize = java.awt.Toolkit.getDefaultToolkit().getScreenSize();
        setBounds((screenSize.width-856)/2, (screenSize.height-593)/2, 856, 593);
    }// </editor-fold>                        

    private void jTable1MouseClicked(java.awt.event.MouseEvent evt) {                                     
           set_Icon();

    }                                    

    private void jButton1ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        JFileChooser chooser = new JFileChooser();
        chooser.showOpenDialog(null);
        File f = chooser.getSelectedFile();
        filename = f.getAbsolutePath();
       jTextField2.setText(filename);

        try {
            File image = new File(filename);
            FileInputStream fis = new FileInputStream(image);
            ByteArrayOutputStream bos = new ByteArrayOutputStream();

            byte buf[] = new byte[1024];
            for (int readNum; (readNum = fis.read(buf)) != -1;) {

                bos.write(buf, 0, readNum);
            }
            category_image = bos.toByteArray();
        } catch (Exception e) {
            JOptionPane.showMessageDialog(null, e);
        }


    }                                        

    private void jButton3ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        EditMenuMain em = new EditMenuMain();
        em.setVisible(true);
        this.setVisible(false);
    }                                        

    private void jButton2ActionPerformed(java.awt.event.ActionEvent evt) {                                         
        try{
            int code=Integer.parseInt(jLabel4.getText());
            String newCatName = jTextField1.getText();

            Connection con = DB_Con.getConnection();
            String sql ="update category set Category_Name='"+ newCatName+"',Category_Image='"+category_image+"' where Category_Code='"+code+"'";
            PreparedStatement st = (PreparedStatement) con.prepareStatement(sql);
            int val = st.executeUpdate(sql);

            if(val==1){

                JOptionPane.showMessageDialog(null, "Updated Category Details Successfuly");
            }
            else{
                JOptionPane.showMessageDialog(null, "Fill all fields");

            }



        }
        catch(Exception e){
        }
         Update_Table();


    }                                        

    private void formWindowOpened(java.awt.event.WindowEvent evt) {                                  
        Update_Table();
    }                                 

    private void formWindowGainedFocus(java.awt.event.WindowEvent evt) {                                       

    }                                      

    /**
    * @param args the command line arguments
    */
    public static void main(String args[]) {
        java.awt.EventQueue.invokeLater(new Runnable() {
            public void run() {
                new EditCategory().setVisible(true);
            }
        });
    }

    // Variables declaration - do not modify                     
    private javax.swing.JButton jButton1;
    private javax.swing.JButton jButton2;
    private javax.swing.JButton jButton3;
    private javax.swing.JLabel jLabel1;
    private javax.swing.JLabel jLabel12;
    private javax.swing.JLabel jLabel2;
    private javax.swing.JLabel jLabel3;
    private javax.swing.JLabel jLabel4;
    private javax.swing.JLabel jLabel5;
    private javax.swing.JPanel jPanel1;
    private javax.swing.JScrollPane jScrollPane1;
    private javax.swing.JTable jTable1;
    private javax.swing.JTextField jTextField1;
    private javax.swing.JTextField jTextField2;
    // End of variables declaration                   

}
4

2 回答 2

0 
Connection connection = null;
    PreparedStatement statement = null;

    ResultSet result;


    public DisplayImage() {
        super("Image Display");
        setSize(600,600);
        connection = getConnection();
        try {
            statement = connection.prepareStatement("select content from image where id=1");
            result = statement.executeQuery();

                byte[] image = null;
                while(result.next()) {
                    image = result.getBytes("content");

                }
                Image img = Toolkit.getDefaultToolkit().createImage(image);
                ImageIcon icon =new ImageIcon(img);
                JLabel lPhoto = new JLabel();
                lPhoto.setIcon(icon);
                add(lPhoto);

        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        setVisible(true);
    }


    public Connection getConnection() {
        Connection connection = null;

        try {
            Class.forName("com.mysql.jdbc.Driver");
            connection = DriverManager.getConnection(
                    "jdbc:mysql://localhost:3306/db_name", "user", "pass");
        } catch (Exception e) {
            System.out.println("Error Occured While Getting the Connection: - "
                    + e);
        }
        return connection;
    }

    public static void main(String[] args) {
        new DisplayImage();
    }

}
于 2013-05-25T09:41:38.313 回答
0

构造ImageIcon函数无法确定您的图像数据的格式。尝试ImageIO.read()方法：http://docs.oracle.com/javase/1.4.2/docs/api/javax/imageio/ImageIO.html#read(java. io.InputStream )

将您的字节数组包装在ByteArrayInputStream：http ://docs.oracle.com/javase/6/docs/api/java/io/ByteArrayInputStream.html

于 2012-07-24T15:01:01.843 回答