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我需要在我的 Java 程序中添加表。我使用 netbeans GUI 来帮助我创建程序。但是当我在上面插入表格时。它不会显示表格。这是我的代码：（请查看方法 setTableItemList() ）

/*
* To change this template, choose Tools | Templates
* and open the template in the editor.
*/
package Program;

import java.awt.BorderLayout; 
import java.awt.CardLayout;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Date;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.table.DefaultTableModel;
import javax.swing.table.TableColumn;
import javax.swing.table.TableModel;
import javax.swing.JTable;

public class MainPage extends javax.swing.JFrame {

/**
 * Creates new form test
 */
public MainPage() {
    initComponents();
}
private Connection connect = null;
private Statement statement = null;
private PreparedStatement preparedStatement = null;
private ResultSet resultSet = null;
private JTable table;
private JScrollPane ScrollPane;
private JPanel topPanel;

/**
 * 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() {

    contentPanel = new javax.swing.JPanel();
    jPanel2 = new javax.swing.JPanel();
    jLabel2 = new javax.swing.JLabel();
    jPanel1 = new javax.swing.JPanel();
    jLabel1 = new javax.swing.JLabel();
    jLabel3 = new javax.swing.JLabel();
    jTextField1 = new javax.swing.JTextField();
    jTextField2 = new javax.swing.JTextField();
    jLabel4 = new javax.swing.JLabel();
    jScrollPane1 = new javax.swing.JScrollPane();
    jTextArea1 = new javax.swing.JTextArea();
    jButton1 = new javax.swing.JButton();
    jPanel3 = new javax.swing.JPanel();
    jPanel4 = new javax.swing.JPanel();
    jMenuBar1 = new javax.swing.JMenuBar();
    jMenu1 = new javax.swing.JMenu();
    jMenuItem2 = new javax.swing.JMenuItem();
    jMenu2 = new javax.swing.JMenu();
    jMenuItem1 = new javax.swing.JMenuItem();
    jMenuItem3 = new javax.swing.JMenuItem();

    setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);

    contentPanel.setLayout(new java.awt.CardLayout());

    jLabel2.setText("WELCOME TO .....");

    org.jdesktop.layout.GroupLayout jPanel2Layout = new org.jdesktop.layout.GroupLayout(jPanel2);
    jPanel2.setLayout(jPanel2Layout);
    jPanel2Layout.setHorizontalGroup(
        jPanel2Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
        .add(jPanel2Layout.createSequentialGroup()
            .add(144, 144, 144)
            .add(jLabel2)
            .addContainerGap(166, Short.MAX_VALUE))
    );
    jPanel2Layout.setVerticalGroup(
        jPanel2Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
        .add(jPanel2Layout.createSequentialGroup()
            .add(125, 125, 125)
            .add(jLabel2)
            .addContainerGap(184, Short.MAX_VALUE))
    );

    contentPanel.add(jPanel2, "card3");

    jLabel1.setText("ID");

    jLabel3.setText("Nama");

    jTextField1.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jTextField1ActionPerformed(evt);
        }
    });

    jLabel4.setText("Keterangan");

    jTextArea1.setColumns(20);
    jTextArea1.setRows(5);
    jScrollPane1.setViewportView(jTextArea1);

    jButton1.setText("Submit");

    org.jdesktop.layout.GroupLayout jPanel1Layout = new org.jdesktop.layout.GroupLayout(jPanel1);
    jPanel1.setLayout(jPanel1Layout);
    jPanel1Layout.setHorizontalGroup(
        jPanel1Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
        .add(jPanel1Layout.createSequentialGroup()
            .add(30, 30, 30)
            .add(jPanel1Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.TRAILING)
                .add(jButton1)
                .add(jPanel1Layout.createSequentialGroup()
                    .add(jPanel1Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
                        .add(jLabel1)
                        .add(jLabel3)
                        .add(jLabel4))
                    .add(24, 24, 24)
                    .add(jPanel1Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING, false)
                        .add(jTextField1)
                        .add(jTextField2)
                        .add(jScrollPane1, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, 248, Short.MAX_VALUE))))
            .addContainerGap(42, Short.MAX_VALUE))
    );
    jPanel1Layout.setVerticalGroup(
        jPanel1Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
        .add(jPanel1Layout.createSequentialGroup()
            .addContainerGap()
            .add(jPanel1Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.BASELINE)
                .add(jLabel1)
                .add(jTextField1, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE))
            .addPreferredGap(org.jdesktop.layout.LayoutStyle.UNRELATED)
            .add(jPanel1Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.BASELINE)
                .add(jLabel3)
                .add(jTextField2, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE))
            .add(18, 18, 18)
            .add(jPanel1Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
                .add(jLabel4)
                .add(jScrollPane1, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, 152, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE))
            .add(18, 18, 18)
            .add(jButton1)
            .addContainerGap(50, Short.MAX_VALUE))
    );

    contentPanel.add(jPanel1, "card2");

    org.jdesktop.layout.GroupLayout jPanel4Layout = new org.jdesktop.layout.GroupLayout(jPanel4);
    jPanel4.setLayout(jPanel4Layout);
    jPanel4Layout.setHorizontalGroup(
        jPanel4Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
        .add(0, 400, Short.MAX_VALUE)
    );
    jPanel4Layout.setVerticalGroup(
        jPanel4Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
        .add(0, 53, Short.MAX_VALUE)
    );

    org.jdesktop.layout.GroupLayout jPanel3Layout = new org.jdesktop.layout.GroupLayout(jPanel3);
    jPanel3.setLayout(jPanel3Layout);
    jPanel3Layout.setHorizontalGroup(
        jPanel3Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
        .add(jPanel4, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
    );
    jPanel3Layout.setVerticalGroup(
        jPanel3Layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
        .add(jPanel3Layout.createSequentialGroup()
            .addContainerGap(270, Short.MAX_VALUE)
            .add(jPanel4, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.PREFERRED_SIZE))
    );

    contentPanel.add(jPanel3, "card4");

    jMenu1.setText("File");

    jMenuItem2.setText("Home");
    jMenuItem2.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jMenuItem2ActionPerformed(evt);
        }
    });
    jMenu1.add(jMenuItem2);

    jMenuBar1.add(jMenu1);

    jMenu2.setText("Edit");

    jMenuItem1.setText("Item");
    jMenuItem1.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jMenuItem1ActionPerformed(evt);
        }
    });
    jMenu2.add(jMenuItem1);

    jMenuItem3.setText("ItemList");
    jMenuItem3.addActionListener(new java.awt.event.ActionListener() {
        public void actionPerformed(java.awt.event.ActionEvent evt) {
            jMenuItem3ActionPerformed(evt);
        }
    });
    jMenu2.add(jMenuItem3);

    jMenuBar1.add(jMenu2);

    setJMenuBar(jMenuBar1);

    org.jdesktop.layout.GroupLayout layout = new org.jdesktop.layout.GroupLayout(getContentPane());
    getContentPane().setLayout(layout);
    layout.setHorizontalGroup(
        layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
        .add(org.jdesktop.layout.GroupLayout.TRAILING, contentPanel, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
    );
    layout.setVerticalGroup(
        layout.createParallelGroup(org.jdesktop.layout.GroupLayout.LEADING)
        .add(contentPanel, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, org.jdesktop.layout.GroupLayout.DEFAULT_SIZE, Short.MAX_VALUE)
    );

    pack();
}// </editor-fold>

//Edit to see what are you searching
public void readDataBase() throws Exception {
    try {

        // This will load the MySQL driver, each DB has its own driver
        Class.forName("com.mysql.jdbc.Driver");
        // Setup the connection with the DB

        connect = DriverManager.getConnection("jdbc:mysql://localhost/amp", "root", "root");

        // Statements allow to issue SQL queries to the database
        statement = connect.createStatement();
        // Result set get the result of the SQL query
        resultSet = statement
                .executeQuery("select * from amp.barang");
        //writeResultSet(resultSet);

        while (resultSet.next()) {
            System.out.println(resultSet.getNString(1));
        }
        //writeMetaData(resultSet);
        // PreparedStatements can use variables and are more efficient

    } catch (Exception e) {
        throw e;
    } finally {
        close();
    }
}

//Show table + collumns name
private void writeMetaData(ResultSet resultSet) throws SQLException {
    //   Now get some metadata from the database
    // Result set get the result of the SQL query

    System.out.println("The columns in the table are: ");

    System.out.println("Table: " + resultSet.getMetaData().getTableName(1));
    for (int i = 1; i <= resultSet.getMetaData().getColumnCount(); i++) {
        System.out.println("Column " + i + " " + resultSet.getMetaData().getColumnName(i));
    }
}

//Edit to set in table
private void insertQueryBarang() throws Exception {
    try {

        // This will load the MySQL driver, each DB has its own driver
        Class.forName("com.mysql.jdbc.Driver");
        // Setup the connection with the DB

        connect = DriverManager.getConnection("jdbc:mysql://localhost/amp", "root", "root");

        // Statements allow to issue SQL queries to the database
        statement = connect.createStatement();
        // Result set get the result of the SQL query
        statement
                .executeUpdate("INSERT INTO `amp`.`barang` (`idbarang`,`namaBarang`,`keteranganBarang`) "
                + "VALUES ('02','B','this is B')");
        //writeResultSet(resultSet);

        //writeMetaData(resultSet);
        // PreparedStatements can use variables and are more efficient

    } catch (Exception e) {
        throw e;
    } finally {
        close();
    }

}

//See result
private void writeResultSet(ResultSet resultSet) throws SQLException {
    // ResultSet is initially before the first data set
    while (resultSet.next()) {
        // It is possible to get the columns via name
        // also possible to get the columns via the column number
        // which starts at 1
        // e.g. resultSet.getSTring(2);
        String user = resultSet.getString("myuser");
        String website = resultSet.getString("webpage");
        String summary = resultSet.getString("summary");
        Date date = resultSet.getDate("datum");
        String comment = resultSet.getString("comments");
        System.out.println("User: " + user);
        System.out.println("Website: " + website);
        System.out.println("Summary: " + summary);
        System.out.println("Date: " + date);
        System.out.println("Comment: " + comment);
    }
}

private void setTableItemList() {
    topPanel = new JPanel();
    topPanel.setLayout(new BorderLayout());
    getContentPane().add(topPanel);

    // Create columns names
    String columnNames[] = {"Column 1", "Column 2", "Column 3"};

    // Create some data
    String dataValues[][] = {
        {"12", "234", "67"},
        {"-123", "43", "853"},
        {"93", "89.2", "109"},
        {"279", "9033", "3092"}
    };

    // Create a new table instance
    table = new JTable(dataValues, columnNames);

    // Add the table to a scrolling pane
    ScrollPane = new JScrollPane(table);
    topPanel.add(ScrollPane, BorderLayout.CENTER);
    jPanel3.add(topPanel);
}

private void close() {
    try {
        if (resultSet != null) {
            resultSet.close();
        }

        if (statement != null) {
            statement.close();
        }

        if (connect != null) {
            connect.close();
        }
    } catch (Exception e) {
    }
}

private void jMenuItem1ActionPerformed(java.awt.event.ActionEvent evt) {                                           
    // TODO add your handling code here:
    CardLayout cl = (CardLayout) (contentPanel.getLayout());
    cl.show(contentPanel, "card2");
}                                          

private void jMenuItem2ActionPerformed(java.awt.event.ActionEvent evt) {                                           
    // TODO add your handling code here:
    CardLayout cl = (CardLayout) (contentPanel.getLayout());
    cl.show(contentPanel, "card3");
}                                          

private void jTextField1ActionPerformed(java.awt.event.ActionEvent evt) {                                            
    // TODO add your handling code here:
}                                           

private void jMenuItem3ActionPerformed(java.awt.event.ActionEvent evt) {                                           
    // TODO add your handling code here:
    CardLayout cl = (CardLayout) (contentPanel.getLayout());
    cl.show(contentPanel, "card4");
}                                          

/**
 * @param args the command line arguments
 */
public static void main(String args[]) throws Exception {
    /* Set the Nimbus look and feel */
    //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
    /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
     * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
     */
    try {
        for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
            if ("Nimbus".equals(info.getName())) {
                javax.swing.UIManager.setLookAndFeel(info.getClassName());
                break;
            }
        }
    } catch (ClassNotFoundException ex) {
        java.util.logging.Logger.getLogger(MainPage.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (InstantiationException ex) {
        java.util.logging.Logger.getLogger(MainPage.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (IllegalAccessException ex) {
        java.util.logging.Logger.getLogger(MainPage.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    } catch (javax.swing.UnsupportedLookAndFeelException ex) {
        java.util.logging.Logger.getLogger(MainPage.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
    }
    //</editor-fold>

    /* Create and display the form */
    MainPage dao = new MainPage();
    //dao.insertQueryBarang();
    dao.readDataBase();
    dao.setTableItemList();
    java.awt.EventQueue.invokeLater(new Runnable() {
        public void run() {
            new MainPage().setVisible(true);
        }
    });
}
// Variables declaration - do not modify
private javax.swing.JPanel contentPanel;
private javax.swing.JButton jButton1;
private javax.swing.JLabel jLabel1;
private javax.swing.JLabel jLabel2;
private javax.swing.JLabel jLabel3;
private javax.swing.JLabel jLabel4;
private javax.swing.JMenu jMenu1;
private javax.swing.JMenu jMenu2;
private javax.swing.JMenuBar jMenuBar1;
private javax.swing.JMenuItem jMenuItem1;
private javax.swing.JMenuItem jMenuItem2;
private javax.swing.JMenuItem jMenuItem3;
private javax.swing.JPanel jPanel1;
private javax.swing.JPanel jPanel2;
private javax.swing.JPanel jPanel3;
private javax.swing.JPanel jPanel4;
private javax.swing.JScrollPane jScrollPane1;
private javax.swing.JTextArea jTextArea1;
private javax.swing.JTextField jTextField1;
private javax.swing.JTextField jTextField2;
// End of variables declaration
}
4

1 回答 1

0

几件事：

1-如果您使用的是 GUI 构建器，您可以“直观地”添加表格并通过其表格模型填充它。

2-在这种方法：

private void setTableItemList() {
    topPanel = new JPanel();
    topPanel.setLayout(new BorderLayout());
    getContentPane().add(topPanel); // <-- topPanel added for first time

    // Create columns names
    String columnNames[] = {"Column 1", "Column 2", "Column 3"};    
    // Create some data
    String dataValues[][] = {
        {"12", "234", "67"},
        {"-123", "43", "853"},
        {"93", "89.2", "109"},
        {"279", "9033", "3092"}
    };

    // Create a new table instance
    table = new JTable(dataValues, columnNames);    
    // Add the table to a scrolling pane
    ScrollPane = new JScrollPane(table);
    topPanel.add(ScrollPane, BorderLayout.CENTER);
    jPanel3.add(topPanel); // <-- topPanel added second time to another container
}

您正在添加topPanel两个不同的容器。从javadoc：

public Component add(Component comp)

将指定的组件附加到此容器的末尾。这是 addImpl(java.awt.Component, java.lang.Object, int) 的便捷方法。

此方法更改与布局相关的信息，因此使组件层次结构无效。如果容器已显示，则必须随后验证层次结构以显示添加的组件。

因此，如果您想topPanel直接将其添加到框架的内容窗格中，请frame.pack()在添加后调用方法。如果要添加，请topPanel在添加jPanel3后调用jPanel3.validate()。

于 2013-09-21T12:13:40.437 回答