Как написать состояние JTable с данными в файле XML, используя XMLEndcoder в Java
Я хочу сохранить JTable в XML-файл с помощью XMLEncoder, Когда мы сохраняем его в файл, получаем исключение:
java.lang.InstantiationException: javax.swing.plaf.basic.BasicTableUI$Handler
Continuing ...
java.lang.Exception: XMLEncoder: discarding statement ColorPropertyTable.removeMouseMotionListener(BasicTableUI$Handler);
Continuing ...
2 ответа
Этот ответ основан на примере aterai. Это немного более полно, потому что это также сохранит имена столбцов:
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));
}
}
}
http://java.sun.com/products/jfc/tsc/articles/persistence4/
http://www.oracle.com/technetwork/java/persistence4-140124.html
Регистрация для уведомлений об исключениях
И XMLEncoder, и XMLDecoder перехватывают исключения и обычно могут восстанавливаться из них, позволяя тем частям архива, которые не затронуты исключением, записывать или читать. Вы можете узнать больше о любых исключениях, возникающих в процессах кодирования и декодирования, зарегистрировав ExceptionListener следующим образом:
...
пример
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 final JTextArea textArea = new JTextArea();
private final String[] columnNames = {"A", "B"};
private final Object[][] data = {
{"aaa", "ccccccc"}, {"bbb", "\u2600\u2601\u2602\u2603"}
};
private DefaultTableModel model = new DefaultTableModel(data, columnNames);
private final JTable table = new JTable(model);
public JComponent makeUI() {
JSplitPane sp = new JSplitPane(JSplitPane.VERTICAL_SPLIT);
sp.setResizeWeight(.5);
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 {
File file = File.createTempFile("output", ".xml");
try (OutputStream os = new BufferedOutputStream(new FileOutputStream(file))) {
XMLEncoder xe = new XMLEncoder(os);
xe.setPersistenceDelegate(
DefaultTableModel.class, new DefaultTableModelPersistenceDelegate());
// xe.setExceptionListener(new ExceptionListener() {
// @Override public void exceptionThrown(Exception exception) {
// //XXX: exception.printStackTrace();
// }
// });
// xe.writeObject(table);
xe.writeObject(model);
//xe.flush();
xe.close();
}
try (Reader r = new BufferedReader(
new InputStreamReader(new FileInputStream(file), "UTF-8"))) {
textArea.read(r, "temp");
}
} catch (IOException ex) {
ex.printStackTrace();
}
}
}));
p.add(new JButton(new AbstractAction("XMLDecoder") {
@Override public void actionPerformed(ActionEvent e) {
try (InputStream is = new BufferedInputStream(
new ByteArrayInputStream(textArea.getText().getBytes("UTF-8")))) {
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(320, 240);
f.setLocationRelativeTo(null);
f.setVisible(true);
}
}
//http://web.archive.org/web/20090806075316/http://java.sun.com/products/jfc/tsc/articles/persistence4/
//http://www.oracle.com/technetwork/java/persistence4-140124.html
class DefaultTableModelPersistenceDelegate extends DefaultPersistenceDelegate {
@Override protected void initialize(
Class<?> type, Object oldInstance, Object newInstance, Encoder encoder) {
super.initialize(type, oldInstance, newInstance, encoder);
DefaultTableModel m = (DefaultTableModel) oldInstance;
// Vector v = m.getDataVector();
// for (int i = 0; i < m.getRowCount(); i++) {
// encoder.writeStatement(
// new Statement(oldInstance, "addRow", new Object[] { (Vector) v.get(i) }));
// }
for (int row = 0; row < m.getRowCount(); row++) {
for (int col = 0; col < m.getColumnCount(); col++) {
Object[] o = new Object[] {m.getValueAt(row, col), row, col};
encoder.writeStatement(new Statement(oldInstance, "setValueAt", o));
}
}
}
}