Values repeating when Populating a JTable

问题

I have a JTable. And I've added the column to it within a method like this.

private void createSearchResultTable() {
    DefaultTableColumnModel columnModel = new DefaultTableColumnModel();
    String columnNames[] = {"Title", "Author", "Edition", "Availability", "Reserve"};

    for (int i = 0; i < columnNames.length; i++) {
        TableColumn column = new TableColumn();
        column.setHeaderValue(columnNames[i]);
        columnModel.addColumn(column);
    }
    tblBookSearchResults.setColumnModel(columnModel);

    ButtonColumn buttonColumn = new ButtonColumn(tblBookSearchResults, reserveBook, 4);
    buttonColumn.setMnemonic(KeyEvent.VK_ENTER);
}

Now I'm populating the JTable with data retrieved from a MySQL database.

private boolean populateSearchResultTable(String title, String author, String publisher) {
    con = DatabaseHandler.connectToDb();
    try {
        if (title.trim().length() != 0) {
            pst = con.prepareStatement("SELECT title, author, edition, status FROM book WHERE title LIKE ? ");
            pst.setString(1, "%" + title + "%");
        }
        else if (author.trim().length() != 0) {
                    // Say, this query is getting executed
            pst = con.prepareStatement("SELECT title, author, edition, status FROM book WHERE author LIKE ? ");
            //pst.setString(1, "%" + author + "%");
                    pst.setString(1, "Dan");
        }
        else if (publisher.trim().length() != 0) {
            pst = con.prepareStatement("SELECT title, author, edition, status FROM book WHERE publisher LIKE ? ");
            pst.setString(1, "%" + publisher + "%");
        }
        rs = pst.executeQuery();
        int rowNum = 0;
        while (rs.next()) {                
            tblBookSearchResults.setValueAt(rs.getString(1), rowNum, 1);
        }
        return true;
    } catch (Exception e) {
        JOptionPane.showMessageDialog(null, e.getLocalizedMessage());
    }
    finally {

    }
    return false;
}

The data set is retrieved without an issue but when I'm setting the values to the JTable, it looks like this.

The first value gets repeated in all columns. I can't figure out why this is happening? Any suggestion on how to correct this would be appreciated.

Thank you.

回答1:

Don't use JTable#setValue when updating a JTable, instead, add new rows or modify existing rows through the model.

Also, you're not incrementing the rowNum value, so you're always interacting with the first row of the table

Simple example

A simple example that uses a Swing Timer to add a new row to the model...

import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.Timer;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.table.DefaultTableModel;

public class TestTableModel01 {

    public static void main(String[] args) {
        new TestTableModel01();
    }

    public TestTableModel01() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                }

                final DefaultTableModel model = new DefaultTableModel(new Object[]{"A", "B", "C", "D", "E"}, 0);
                JTable table = new JTable(model);

                JFrame frame = new JFrame("Test");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setLayout(new BorderLayout());
                frame.add(new JScrollPane(table));
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);

                Timer timer = new Timer(500, new ActionListener() {
                    @Override
                    public void actionPerformed(ActionEvent e) {
                        if (model.getRowCount() < 100) {
                            int row = model.getRowCount();
                            model.addRow(new Object[]{
                                row + "x" + 0,
                                row + "x" + 1,
                                row + "x" + 2,
                                row + "x" + 3,
                                row + "x" + 4
                            });
                        } else {
                            ((Timer)(e.getSource())).stop();
                        }
                    }
                });
                timer.start();
            }
        });
    }
}

来源：https://stackoverflow.com/questions/16496126/values-repeating-when-populating-a-jtable