标签：java swing jtable xmlencoder

我想使用XMLEncoder将JTable保存在xml文件中.
当我们将其保存到文件中时,获取异常：

java.lang.InstantiationException: javax.swing.plaf.basic.BasicTableUI$Handler
Continuing ...
java.lang.Exception: XMLEncoder: discarding statement ColorPropertyTable.removeMouseMotionListener(BasicTableUI$Handler);
Continuing ...

解决方法:

这个答案基于aterai的例子.它更完整,因为它也会保留列名：

import java.awt.*;
import java.awt.event.*;
import java.beans.*;
import java.io.*;
import java.util.Vector;
import javax.swing.*;
import javax.swing.table.*;

public class DefaultTableModelPersistenceDelegateTest
{
    private File file = new File("TableModel.xml");
    private final JTextArea textArea = new JTextArea();

    private final String[] columnNames = {"Column1", "Column2"};

    private final Object[][] data =
    {
        {"aaa", new Integer(1)},
        {"bbb\u2600", new Integer(2)}
    };

    private DefaultTableModel model = new DefaultTableModel(data, columnNames);
    private final JTable table = new JTable(model);

    public JComponent makeUI()
    {
        model.setColumnCount(5);
        JSplitPane sp = new JSplitPane(JSplitPane.VERTICAL_SPLIT);
        sp.setResizeWeight(.3);
        sp.setTopComponent(new JScrollPane(table));
        sp.setBottomComponent(new JScrollPane(textArea));

        JPanel p = new JPanel();
        p.add(new JButton(new AbstractAction("XMLEncoder")
        {
            @Override
            public void actionPerformed(ActionEvent e)
            {
                try
                {
                    OutputStream os = new BufferedOutputStream(new FileOutputStream(file));
                    XMLEncoder xe = new XMLEncoder(os);
                    xe.setPersistenceDelegate(DefaultTableModel.class, new DefaultTableModelPersistenceDelegate2());
                    xe.writeObject(model);
                    xe.close();

                    Reader r = new BufferedReader(new InputStreamReader(new FileInputStream(file), "UTF-8"));
                    textArea.read(r, null);
                }
                catch (IOException ex)
                {
                    ex.printStackTrace();
                }
            }
        }));

        p.add(new JButton(new AbstractAction("XMLDecoder")
        {
            @Override
            public void actionPerformed(ActionEvent e)
            {
                try
                {
                    InputStream is = new BufferedInputStream( new FileInputStream( file ));
                    XMLDecoder xd = new XMLDecoder(is);
                    model = (DefaultTableModel)xd.readObject();
                    table.setModel(model);
                }
                catch (IOException ex)
                {
                    ex.printStackTrace();
                }
            }
        }));

        p.add(new JButton(new AbstractAction("clear")
        {
            @Override
            public void actionPerformed(ActionEvent e)
            {
                model = new DefaultTableModel();
                table.setModel(model);
            }
        }));

        JPanel pnl = new JPanel(new BorderLayout());
        pnl.add(sp);
        pnl.add(p, BorderLayout.SOUTH);
        return pnl;
    }

    public static void main(String[] args)
    {
        EventQueue.invokeLater(new Runnable()
        {
            @Override public void run()
            {
                createAndShowGUI();
            }
        });
    }

    public static void createAndShowGUI()
    {
        JFrame f = new JFrame();
        f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        f.getContentPane().add(new DefaultTableModelPersistenceDelegateTest().makeUI());
        f.setSize(420, 340);
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }
}

//http://www.oracle.com/technetwork/java/persistence4-140124.html

class DefaultTableModelPersistenceDelegate extends DefaultPersistenceDelegate
{
    //  Initially creates an empty DefaultTableModel. The columns are created
    //  and finally each row of data is added to the model.

    @Override
    protected void initialize(Class<?> type, Object oldInstance, Object newInstance, Encoder encoder)
    {
        DefaultTableModel model= (DefaultTableModel)oldInstance;

        Vector<String> columnNames = new Vector<String>(model.getColumnCount());

        for (int i = 0; i < model.getColumnCount(); i++)
        {
            columnNames.add( model.getColumnName(i) );
        }

        Object[] columnNamesData = new Object[] { columnNames };
        encoder.writeStatement(new Statement(oldInstance, "setColumnIdentifiers", columnNamesData));

        Vector row = model.getDataVector();

        for (int i = 0; i < model.getRowCount(); i++)
        {
            Object[] rowData = new Object[] { row.get(i) };
            encoder.writeStatement(new Statement(oldInstance, "addRow", rowData));
        }
    }
}

标签：java,swing,jtable,xmlencoder
来源： https://codeday.me/bug/20190927/1824716.html

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