How to Populate a JTable from a ResultSet and Avoid IllegalStateException?-javaTutorial-php.cn

How to Populate a JTable from a ResultSet and Avoid IllegalStateException?

Linda Hamilton

Release： 2024-12-01 05:40:17

Original

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How to Populate a JTable from a ResultSet and Avoid IllegalStateException?

Populating JTable from a ResultSet

Problem Description

Within a GUI application, a user is encountering an IllegalStateException when updating a DefaultTableModel from a ResultSet. The goal is to display the contents of the ResultSet within a JTable.

Solution 1

The following code provides a straightforward method to create a DefaultTableModel from a ResultSet:

public static DefaultTableModel buildTableModel(ResultSet rs)
        throws SQLException {

    ResultSetMetaData metaData = rs.getMetaData();

    // Column names
    Vector<String> columnNames = new Vector<>();
    int columnCount = metaData.getColumnCount();
    for (int column = 1; column <= columnCount; column++) {
        columnNames.add(metaData.getColumnName(column));
    }

    // Table data
    Vector<Vector<Object>> data = new Vector<>();
    while (rs.next()) {
        Vector<Object> vector = new Vector<>();
        for (int columnIndex = 1; columnIndex <= columnCount; columnIndex++) {
            vector.add(rs.getObject(columnIndex));
        }
        data.add(vector);
    }

    return new DefaultTableModel(data, columnNames);

}

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Utilizing this method, the table can be constructed as follows:

JTable table = new JTable(buildTableModel(rs));

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Solution 2 (Using SwingWorker)

This solution employs a SwingWorker to perform the data loading in a separate thread, enhancing the UI responsiveness. It also utilizes the try-with-resources statement for improved resource management:

public class GUI extends JFrame {

    // ...

    private void loadData() {
        button.setEnabled(false);

        try (Connection conn = DriverManager.getConnection(url, usr, pwd);
             Statement stmt = conn.createStatement()) {

            ResultSet rs = stmt.executeQuery("select * from customer");
            ResultSetMetaData metaData = rs.getMetaData();

            // ...

            while (rs.next()) {
                // ...
            }

            tableModel.setDataVector(data, columnNames);
        } catch (Exception e) {
            // ...
        }
        button.setEnabled(true);
    }

}

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