Get started with a simple JTable

Using a simple Swing table in your GUI apps doesn’t require a lot of code. Create a one-dimensional containing the table headers and a two-dimensional array that represents the contents. Create a JTable with those two arrays and add it to the container. This is the simpliest example. All cells are editable and column widths can be adjusted.
If you want to have more control over your JTables, you can create your own TableModel, CellRenderer and CellEditor.

import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
 
public class Main extends JFrame 
{
   public Main() {
      super("Table example, Wines from Bordeaux");
 
      Object[][] tabledata = {
            { "Chateau Meyney, St. Estephe", 	   new Integer(1994), "$18.75"},
            { "Chateau Montrose, St. Estephe", 	   new Integer(1975), "$54.25" },
            { "Chateau Gloria, St. Julien", 	   new Integer(1993), "$22.99" },
            { "Chateau Beychevelle, St. Julien",   new Integer(1970), "$61.63" },
            { "Chateau La Tour de Mons, Margeaux", new Integer(1975), "$57.03" },
            { "Chateau Brane-Cantenac, Margeaux",  new Integer(1978), "$49.92" },
      };
 
      String columnheaders[] = { "Wine", "Vintage", "Price" };
 
      JTable table = new JTable(tabledata, columnheaders);
      table.setPreferredScrollableViewportSize(new Dimension(500, 70));
      JScrollPane scrollPane = new JScrollPane(table);
 
      getContentPane().add(scrollPane);
 
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            System.exit(0);
         }
      });
 
      pack();
   }
 
   public static void main(String []args) {
      Main main = new Main();
      main.show();
   }
}

Creating a JTable with multiline cells

Courtesy of Nobuo Tamemasa (http://www2.gol.com/users/tame/swing/examples/JTableExamples1.html)



MultiLineCellExample.java:

import javax.swing.*;
import javax.swing.table.*;
import javax.swing.border.*;
import java.util.*;
import java.awt.*;
import java.awt.event.*;
 
/**
 * @version 1.0 11/09/98
 */
public class MultiLineCellExample extends JFrame {
  MultiLineCellExample() {
    super( "Multi-Line Cell Example" );
 
    DefaultTableModel dm = new DefaultTableModel() {
      public Class getColumnClass(int columnIndex) {
        return String.class;
      }
    };
    dm.setDataVector(new Object[][]{{"ana","bnb","cnc"},
                                    {"AnA","BnB","CnC"}},
                     new Object[]{"1","2","3"});
 
    JTable table = new JTable( dm );
    
    int lines = 2;
    table.setRowHeight( table.getRowHeight() * lines);
    
    //
    // table.setRowHeight(0);
    //
    // I got "java.lang.IllegalArgumentException: New row height less than 1"
    //
    table.setDefaultRenderer(String.class, new MultiLineCellRenderer());
    JScrollPane scroll = new JScrollPane( table );
    getContentPane().add( scroll );
    setSize( 400, 130 );
    setVisible(true);
  }
 
  public static void main(String[] args) {
    MultiLineCellExample frame = new MultiLineCellExample();
    frame.addWindowListener( new WindowAdapter() {
      public void windowClosing( WindowEvent e ) {
        System.exit(0);
      }
    });
  }
}
import javax.swing.*;
import javax.swing.table.*;
import javax.swing.border.*;
import java.awt.*;
 
/**
 * @version 1.0 11/09/98
 */
 
public class MultiLineCellRenderer extends JTextArea implements TableCellRenderer {
 
  public MultiLineCellRenderer() {
    setLineWrap(true);
    setWrapStyleWord(true);
    setOpaque(true);
  }
 
  public Component getTableCellRendererComponent(JTable table, Object value,
               boolean isSelected, boolean hasFocus, int row, int column) {
    if (isSelected) {
      setForeground(table.getSelectionForeground());
      setBackground(table.getSelectionBackground());
    } else {
      setForeground(table.getForeground());
      setBackground(table.getBackground());
    }
    setFont(table.getFont());
    if (hasFocus) {
      setBorder( UIManager.getBorder("Table.focusCellHighlightBorder") );
      if (table.isCellEditable(row, column)) {
        setForeground( UIManager.getColor("Table.focusCellForeground") );
        setBackground( UIManager.getColor("Table.focusCellBackground") );
      }
    } else {
      setBorder(new EmptyBorder(1, 2, 1, 2));
    }
    setText((value == null) ? "" : value.toString());
    return this;
  }
}

Having multi-font cells in a JTable

Courtesy of Nobuo Tamemasa (http://www2.gol.com/users/tame/swing/examples/JTableExamples1.html)



MultiFontCellTableExample.java:

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.table.*;
import javax.swing.border.*;
 
/**
 * @version 1.0 11/22/98
 */
public class MultiFontCellTableExample extends JFrame {
 
  public MultiFontCellTableExample() {
    super( "Multi-Font Cell Example" ); 
     
    AttributiveCellTableModel ml = new AttributiveCellTableModel(8,3);
    CellFont cellAtt =(CellFont)ml.getCellAttribute();
    JTable table = new JTable( ml );
    table.setRowHeight(26);
    table.setCellSelectionEnabled(true);
    table.setSelectionMode(ListSelectionModel.SINGLE_INTERVAL_SELECTION);
    table.setDefaultRenderer(Object.class ,new AttributiveCellRenderer());
    JScrollPane scroll = new JScrollPane( table );
 
    FontPanel fontPanel = new FontPanel(table, cellAtt);
    
    Box box = new Box(BoxLayout.X_AXIS);
    box.add(scroll);
    box.add(new JSeparator(SwingConstants.HORIZONTAL));
    box.add(fontPanel);
    getContentPane().add( box );
    setSize( 400, 200 );
    setVisible(true);
  }
 
  class FontPanel extends JPanel {
    String[] str_size  = {"10","12","14","16","20","24"};
    String[] str_style = {"PLAIN","BOLD","ITALIC"};
    JComboBox name,style,size;
 
    FontPanel(final JTable table, final CellFont cellAtt) {
      setLayout(new BoxLayout(this,BoxLayout.Y_AXIS));
      Box box = new Box(BoxLayout.X_AXIS);
      JPanel p2 = new JPanel(new GridLayout(3,1));
      JPanel p3 = new JPanel(new GridLayout(3,1));
      JPanel p4 = new JPanel(new FlowLayout());
      p2.add(new JLabel("Name:"));
      p2.add(new JLabel("Style:"));    
      p2.add(new JLabel("Size:"));
      Toolkit toolkit = Toolkit.getDefaultToolkit();
      name  = new JComboBox(toolkit.getFontList());
      style = new JComboBox(str_style);
      size  = new JComboBox(str_size);
      size.setEditable(true);
      JButton b_apply   = new JButton("Apply");
      b_apply.addActionListener(new ActionListener() {
        public void actionPerformed(ActionEvent e) {
          int[] columns = table.getSelectedColumns();
          int[] rows    = table.getSelectedRows();
          if ((rows == null) || (columns == null)) return;
          if ((rows.length<1)||(columns.length<1)) return;
          Font font = new Font((String)name.getSelectedItem(),
                              style.getSelectedIndex(),
              Integer.parseInt((String)size.getSelectedItem()));
          cellAtt.setFont(font, rows, columns);
          table.clearSelection();
          table.revalidate();
          table.repaint();        
        }
      });
      p3.add(name);
      p3.add(style);
      p3.add(size);
      p4.add(b_apply);
      box.add(p2);
      box.add(p3);
      add(box);
      add(p4);
    }
  }
   
  public static void main(String[] args) {
    MultiFontCellTableExample frame = new MultiFontCellTableExample();
    frame.addWindowListener( new WindowAdapter() {
      public void windowClosing( WindowEvent e ) {
        System.exit(0);
      }
    });
  }
}

AttributiveCellTableModel.java:

import java.util.*;
import java.awt.*;
import javax.swing.*;
import javax.swing.table.*;
import javax.swing.event.*;
 
 
/**
 * @version 1.0 11/22/98
 */
 
public class AttributiveCellTableModel extends DefaultTableModel {
 
  protected CellAttribute cellAtt;
    
  public AttributiveCellTableModel() {
    this((Vector)null, 0);
  }
  public AttributiveCellTableModel(int numRows, int numColumns) {
    Vector names = new Vector(numColumns);
    names.setSize(numColumns);
    setColumnIdentifiers(names);
    dataVector = new Vector();
    setNumRows(numRows);
    cellAtt = new DefaultCellAttribute(numRows,numColumns);
  }
  public AttributiveCellTableModel(Vector columnNames, int numRows) {
    setColumnIdentifiers(columnNames);
    dataVector = new Vector();
    setNumRows(numRows);
    cellAtt = new DefaultCellAttribute(numRows,columnNames.size());
  }
  public AttributiveCellTableModel(Object[] columnNames, int numRows) {
    this(convertToVector(columnNames), numRows);
  }  
  public AttributiveCellTableModel(Vector data, Vector columnNames) {
    setDataVector(data, columnNames);
  }
  public AttributiveCellTableModel(Object[][] data, Object[] columnNames) {
    setDataVector(data, columnNames);
  }
 
     
  public void setDataVector(Vector newData, Vector columnNames) {
    if (newData == null)
      throw new IllegalArgumentException("setDataVector() - Null parameter");
    dataVector = new Vector(0);
    setColumnIdentifiers(columnNames);
    dataVector = newData;
    
    //
    cellAtt = new DefaultCellAttribute(dataVector.size(),
                                       columnIdentifiers.size());
    
    newRowsAdded(new TableModelEvent(this, 0, getRowCount()-1,
                 TableModelEvent.ALL_COLUMNS, TableModelEvent.INSERT));
  }
 
  public void addColumn(Object columnName, Vector columnData) {
    if (columnName == null)
      throw new IllegalArgumentException("addColumn() - null parameter");
    columnIdentifiers.addElement(columnName);
    int index = 0;
    Enumeration enumeration = dataVector.elements();
    while (enumeration.hasMoreElements()) {
      Object value;
      if ((columnData != null) && (index < columnData.size()))
          value = columnData.elementAt(index);
      else
        value = null;
      ((Vector)enumeration.nextElement()).addElement(value);
      index++;
    }
 
    //
    cellAtt.addColumn();
 
    fireTableStructureChanged();
  }
 
  public void addRow(Vector rowData) {
    Vector newData = null;
    if (rowData == null) {
      newData = new Vector(getColumnCount());
    }
    else {
      rowData.setSize(getColumnCount());
    }
    dataVector.addElement(newData);
 
    //
    cellAtt.addRow();
 
    newRowsAdded(new TableModelEvent(this, getRowCount()-1, getRowCount()-1,
       TableModelEvent.ALL_COLUMNS, TableModelEvent.INSERT));
  }
 
  public void insertRow(int row, Vector rowData) {
    if (rowData == null) {
      rowData = new Vector(getColumnCount());
    }
    else {
      rowData.setSize(getColumnCount());
    }
 
    dataVector.insertElementAt(rowData, row);
 
    //
    cellAtt.insertRow(row);
 
    newRowsAdded(new TableModelEvent(this, row, row,
       TableModelEvent.ALL_COLUMNS, TableModelEvent.INSERT));
  }
 
  public CellAttribute getCellAttribute() {
    return cellAtt;
  }
 
  public void setCellAttribute(CellAttribute newCellAtt) {
    int numColumns = getColumnCount();
    int numRows    = getRowCount();
    if ((newCellAtt.getSize().width  != numColumns) ||
        (newCellAtt.getSize().height != numRows)) {
      newCellAtt.setSize(new Dimension(numRows, numColumns));
    }
    cellAtt = newCellAtt;
    fireTableDataChanged();
  }
 
  /*
  public void changeCellAttribute(int row, int column, Object command) {
    cellAtt.changeAttribute(row, column, command);
  }
 
  public void changeCellAttribute(int[] rows, int[] columns, Object command) {
    cellAtt.changeAttribute(rows, columns, command);
  }
  */
     
}

DefaultCellAttribute.java:

import java.awt.*;
 
/** 
 * @version 1.0 11/22/98
 */
 
public class DefaultCellAttribute 
//    implements CellAttribute ,CellSpan  {
      implements CellAttribute ,CellSpan ,ColoredCell ,CellFont {

  //
  // !!!! CAUTION !!!!!
  // these values must be synchronized to Table data
  //
  protected int rowSize;
  protected int columnSize;
  protected int[][][] span;                   // CellSpan
  protected Color[][] foreground;             // ColoredCell
  protected Color[][] background;             //
  protected Font[][]  font;                   // CellFont
   
  public DefaultCellAttribute() {
    this(1,1);
  }
   
  public DefaultCellAttribute(int numRows, int numColumns) {
    setSize(new Dimension(numColumns, numRows));
  }
 
  protected void initValue() {
    for(int i=0; i<span.length;i++) {
      for(int j=0; j<span[i].length; j++) {
        span[i][j][CellSpan.COLUMN] = 1;
        span[i][j][CellSpan.ROW]    = 1;
      }
    }
  }
 
 
  //
  // CellSpan
  //
  public int[] getSpan(int row, int column) {
    if (isOutOfBounds(row, column)) {
      int[] ret_code = {1,1};
      return ret_code;
    }
    return span[row][column];
  }
 
  public void setSpan(int[] span, int row, int column) {
    if (isOutOfBounds(row, column)) return;
    this.span[row][column] = span;
  }
       
  public boolean isVisible(int row, int column) {
    if (isOutOfBounds(row, column)) return false;
    if ((span[row][column][CellSpan.COLUMN] < 1)
      ||(span[row][column][CellSpan.ROW]    < 1)) return false;
    return true;
  }
 
  public void combine(int[] rows, int[] columns) {
    if (isOutOfBounds(rows, columns)) return;
    int    rowSpan  = rows.length;
    int columnSpan  = columns.length;
    int startRow    = rows[0];
    int startColumn = columns[0];
    for (int i=0;i<rowSpan;i++) {
      for (int j=0;j<columnSpan;j++) {
        if ((span[startRow +i][startColumn +j][CellSpan.COLUMN] != 1)
          ||(span[startRow +i][startColumn +j][CellSpan.ROW]    != 1)) {
          //System.out.println("can't combine");
          return ;
        }
      }
    }
    for (int i=0,ii=0;i<rowSpan;i++,ii--) {
      for (int j=0,jj=0;j<columnSpan;j++,jj--) {
        span[startRow +i][startColumn +j][CellSpan.COLUMN] = jj;
        span[startRow +i][startColumn +j][CellSpan.ROW]    = ii;
        //System.out.println("r " +ii +"  c " +jj);
      }
    }
    span[startRow][startColumn][CellSpan.COLUMN] = columnSpan;
    span[startRow][startColumn][CellSpan.ROW]    =    rowSpan;
    
  }
 
  public void split(int row, int column) {
    if (isOutOfBounds(row, column)) return;
    int columnSpan = span[row][column][CellSpan.COLUMN];
    int    rowSpan = span[row][column][CellSpan.ROW];
    for (int i=0;i<rowSpan;i++) {
      for (int j=0;j<columnSpan;j++) {
        span[row +i][column +j][CellSpan.COLUMN] = 1;
        span[row +i][column +j][CellSpan.ROW]    = 1;
      }
    }
  }
 
 
  //
  // ColoredCell
  //
  public Color getForeground(int row, int column) {
    if (isOutOfBounds(row, column)) return null;
    return foreground[row][column];
  }
  public void setForeground(Color color, int row, int column) {
    if (isOutOfBounds(row, column)) return;
    foreground[row][column] = color;
  }
  public void setForeground(Color color, int[] rows, int[] columns) {
    if (isOutOfBounds(rows, columns)) return;
    setValues(foreground, color, rows, columns);
  }
  public Color getBackground(int row, int column) {
    if (isOutOfBounds(row, column)) return null;
    return background[row][column];
  }
  public void setBackground(Color color, int row, int column) {
    if (isOutOfBounds(row, column)) return;
    background[row][column] = color;
  }
  public void setBackground(Color color, int[] rows, int[] columns) {
    if (isOutOfBounds(rows, columns)) return;
    setValues(background, color, rows, columns);
  }
  //
 
 
  //
  // CellFont
  //
  public Font getFont(int row, int column) {
    if (isOutOfBounds(row, column)) return null;
    return font[row][column];
  }
  public void setFont(Font font, int row, int column) {
    if (isOutOfBounds(row, column)) return;
    this.font[row][column] = font;
  }
  public void setFont(Font font, int[] rows, int[] columns) {
    if (isOutOfBounds(rows, columns)) return;
    setValues(this.font, font, rows, columns);
  }
  // 
 
 
  //
  // CellAttribute
  //
  public void addColumn() {
    int[][][] oldSpan = span;
    int numRows    = oldSpan.length;
    int numColumns = oldSpan[0].length;
    span = new int[numRows][numColumns + 1][2];
    System.arraycopy(oldSpan,0,span,0,numRows);
    for (int i=0;i<numRows;i++) {
      span[i][numColumns][CellSpan.COLUMN] = 1;
      span[i][numColumns][CellSpan.ROW]    = 1;
    }
  }
 
  public void addRow() {
    int[][][] oldSpan = span;
    int numRows    = oldSpan.length;
    int numColumns = oldSpan[0].length;
    span = new int[numRows + 1][numColumns][2];
    System.arraycopy(oldSpan,0,span,0,numRows);
    for (int i=0;i<numColumns;i++) {
      span[numRows][i][CellSpan.COLUMN] = 1;
      span[numRows][i][CellSpan.ROW]    = 1;
    }
  }
 
  public void insertRow(int row) {
    int[][][] oldSpan = span;
    int numRows    = oldSpan.length;
    int numColumns = oldSpan[0].length;
    span = new int[numRows + 1][numColumns][2];
    if (0 < row) {
      System.arraycopy(oldSpan,0,span,0,row-1);
    }
    System.arraycopy(oldSpan,0,span,row,numRows - row);
    for (int i=0;i<numColumns;i++) {
      span[row][i][CellSpan.COLUMN] = 1;
      span[row][i][CellSpan.ROW]    = 1;
    }
  }
 
  public Dimension getSize() {
    return new Dimension(rowSize, columnSize);
  }
 
  public void setSize(Dimension size) {
    columnSize = size.width;
    rowSize    = size.height;
    span = new int[rowSize][columnSize][2];   // 2: COLUMN,ROW
    foreground = new Color[rowSize][columnSize];
    background = new Color[rowSize][columnSize];
    font = new Font[rowSize][columnSize];
    initValue();
  }
 
  /*
  public void changeAttribute(int row, int column, Object command) {
  }
 
  public void changeAttribute(int[] rows, int[] columns, Object command) {
  }
  */
 
  protected boolean isOutOfBounds(int row, int column) {
    if ((row    < 0)||(rowSize    <= row)
      ||(column < 0)||(columnSize <= column)) {
      return true;
    }
    return false;
  }
 
  protected boolean isOutOfBounds(int[] rows, int[] columns) {
    for (int i=0;i<rows.length;i++) {
      if ((rows[i] < 0)||(rowSize <= rows[i])) return true;
    }
    for (int i=0;i<columns.length;i++) {
      if ((columns[i] < 0)||(columnSize <= columns[i])) return true;
    }
    return false;
  }
 
  protected void setValues(Object[][] target, Object value,
                           int[] rows, int[] columns) {
    for (int i=0;i<rows.length;i++) {
      int row = rows[i];
      for (int j=0;j<columns.length;j++) {
        int column = columns[j];
        target[row][column] = value;
      }
    }
  }
}

CellAttribute.java:

import java.awt.*;

/**
 * @version 1.0 11/22/98
 */

public interface CellAttribute {
  public void addColumn();
  public void addRow();
  public void insertRow(int row);
  public Dimension getSize();
  public void setSize(Dimension size);
}

ColoredCell.java:

import java.awt.*;
 
/**
 * @version 1.0 11/22/98
 */
 
public interface ColoredCell {
   
  public Color getForeground(int row, int column);
  public void setForeground(Color color, int row, int column);
  public void setForeground(Color color, int[] rows, int[] columns);
  public Color getBackground(int row, int column);
  public void setBackground(Color color, int row, int column);
  public void setBackground(Color color, int[] rows, int[] columns);
}

CellFont.java:

/*
 * (swing1.1beta3)
 * 
 */
 
import java.awt.*;
 
/**
 * @version 1.0 11/22/98
 */
 
public interface CellFont {
  public Font getFont(int row, int column);
  public void setFont(Font font, int row, int column);
  public void setFont(Font font, int[] rows, int[] columns);
}

CellSpan.java:

/*
 * (swing1.1beta3)
 * 
 */
 
/**
 * @version 1.0 11/22/98
 */
 
public interface CellSpan {
  public final int ROW    = 0;
  public final int COLUMN = 1;
   
  public int[] getSpan(int row, int column);
  public void setSpan(int[] span, int row, int column);
   
  public boolean isVisible(int row, int column);
 
  public void combine(int[] rows, int[] columns);
  public void split(int row, int column);
}

MultiSpanCellTable.java:

import java.util.*;
import java.awt.*;
import javax.swing.*;
import javax.swing.table.*;
import javax.swing.plaf.basic.*;
import javax.swing.event.*;
 
/**
 * @version 1.0 11/26/98
 */
 
public class MultiSpanCellTable extends JTable {
 
  public MultiSpanCellTable(TableModel model) {
    super(model);
    setUI(new MultiSpanCellTableUI());
    getTableHeader().setReorderingAllowed(false);
    setCellSelectionEnabled(true);
    setSelectionMode(ListSelectionModel.SINGLE_INTERVAL_SELECTION);
  }
   
  public Rectangle getCellRect(int row, int column, boolean includeSpacing) {
    Rectangle sRect = super.getCellRect(row,column,includeSpacing);
    if ((row <0) || (column<0) ||
        (getRowCount() <= row) || (getColumnCount() <= column)) {
        return sRect;
    }
    CellSpan cellAtt = (CellSpan)((AttributiveCellTableModel)getModel()).getCellAttribute();
    if (! cellAtt.isVisible(row,column)) {
      int temp_row    = row;
      int temp_column = column;
      row    += cellAtt.getSpan(temp_row,temp_column)[CellSpan.ROW];
      column += cellAtt.getSpan(temp_row,temp_column)[CellSpan.COLUMN];      
    }
    int[] n = cellAtt.getSpan(row,column);
 
    int index = 0;
    int columnMargin = getColumnModel().getColumnMargin();
    Rectangle cellFrame = new Rectangle();
    int aCellHeight = rowHeight + rowMargin;
    cellFrame.y = row * aCellHeight;
    cellFrame.height = n[CellSpan.ROW] * aCellHeight;
     
    Enumeration enumeration = getColumnModel().getColumns();
    while (enumeration.hasMoreElements()) {
      TableColumn aColumn = (TableColumn)enumeration.nextElement();
      cellFrame.width = aColumn.getWidth() + columnMargin;
      if (index == column) break;
      cellFrame.x += cellFrame.width;
      index++;
    }
    for (int i=0;i< n[CellSpan.COLUMN]-1;i++) {
      TableColumn aColumn = (TableColumn)enumeration.nextElement();
      cellFrame.width += aColumn.getWidth() + columnMargin;
    }
     
    if (!includeSpacing) {
      Dimension spacing = getIntercellSpacing();
      cellFrame.setBounds(cellFrame.x +      spacing.width/2,
                          cellFrame.y +      spacing.height/2,
                          cellFrame.width -  spacing.width,
                          cellFrame.height - spacing.height);
    }
    return cellFrame;
  }
   
   
  private int[] rowColumnAtPoint(Point point) {
    int[] retValue = {-1,-1};
    int row = point.y / (rowHeight + rowMargin);
    if ((row <0)||(getRowCount() <= row)) return retValue;
    int column = getColumnModel().getColumnIndexAtX(point.x);
 
    CellSpan cellAtt = (CellSpan)((AttributiveCellTableModel)getModel()).getCellAttribute();
 
    if (cellAtt.isVisible(row,column)) {
      retValue[CellSpan.COLUMN] = column;
      retValue[CellSpan.ROW   ] = row;
      return retValue;
    }
    retValue[CellSpan.COLUMN] = column + cellAtt.getSpan(row,column)[CellSpan.COLUMN];
    retValue[CellSpan.ROW   ] = row + cellAtt.getSpan(row,column)[CellSpan.ROW];
    return retValue;
  }
 
   
  public int rowAtPoint(Point point) {
    return rowColumnAtPoint(point)[CellSpan.ROW];
  }
 
  public int columnAtPoint(Point point) {
    return rowColumnAtPoint(point)[CellSpan.COLUMN];
  }
  
  public void columnSelectionChanged(ListSelectionEvent e) {
    repaint();
  }
 
  public void valueChanged(ListSelectionEvent e) {
    int firstIndex = e.getFirstIndex();
    int  lastIndex = e.getLastIndex();
    if (firstIndex == -1 && lastIndex == -1) { // Selection cleared.
      repaint();
    }
    Rectangle dirtyRegion = getCellRect(firstIndex, 0, false);
    int numCoumns = getColumnCount();
    int index = firstIndex;
    for (int i=0;i<numCoumns;i++) {
      dirtyRegion.add(getCellRect(index, i, false));
    }
    index = lastIndex;
    for (int i=0;i<numCoumns;i++) {
      dirtyRegion.add(getCellRect(index, i, false));
    }
    repaint(dirtyRegion.x, dirtyRegion.y, dirtyRegion.width, dirtyRegion.height);
  }
  
}

MultiSpanCellTableUI.java:

import java.util.*;
import java.awt.*;
import javax.swing.*;
import javax.swing.table.*;
import javax.swing.plaf.basic.*;
 
/**
 * @version 1.0 11/26/98
 */
 
public class MultiSpanCellTableUI extends BasicTableUI {
 
  public void paint(Graphics g, JComponent c) {
    Rectangle oldClipBounds = g.getClipBounds();
    Rectangle clipBounds    = new Rectangle(oldClipBounds);
    int tableWidth   = table.getColumnModel().getTotalColumnWidth();
    clipBounds.width = Math.min(clipBounds.width, tableWidth);
    g.setClip(clipBounds);
 
    int firstIndex = table.rowAtPoint(new Point(0, clipBounds.y));
    int  lastIndex = table.getRowCount()-1;
 
    Rectangle rowRect = new Rectangle(0,0,
      tableWidth, table.getRowHeight() + table.getRowMargin());
    rowRect.y = firstIndex*rowRect.height;
 
    for (int index = firstIndex; index <= lastIndex; index++) {
      if (rowRect.intersects(clipBounds)) {
        //System.out.println();                  // debug
        //System.out.print("" + index +": ");    // row
        paintRow(g, index);
      }
      rowRect.y += rowRect.height;
    }
    g.setClip(oldClipBounds);
  }
 
  private void paintRow(Graphics g, int row) {
    Rectangle rect = g.getClipBounds();
    boolean drawn  = false;
    
    AttributiveCellTableModel tableModel = (AttributiveCellTableModel)table.getModel();
    CellSpan cellAtt = (CellSpan)tableModel.getCellAttribute();
    int numColumns = table.getColumnCount();
 
    for (int column = 0; column < numColumns; column++) {
      Rectangle cellRect = table.getCellRect(row,column,true);
      int cellRow,cellColumn;
      if (cellAtt.isVisible(row,column)) {
        cellRow    = row;
        cellColumn = column;
          //  System.out.print("   "+column+" ");  // debug
      } else {
        cellRow    = row + cellAtt.getSpan(row,column)[CellSpan.ROW];
        cellColumn = column + cellAtt.getSpan(row,column)[CellSpan.COLUMN];
          //  System.out.print("  ("+column+")");  // debug
      }
      if (cellRect.intersects(rect)) {
        drawn = true;
        paintCell(g, cellRect, cellRow, cellColumn);
      } else {
        if (drawn) break;
      } 
    }
 
  }
 
  private void paintCell(Graphics g, Rectangle cellRect, int row, int column) {
    int spacingHeight = table.getRowMargin();
    int spacingWidth  = table.getColumnModel().getColumnMargin();
 
    Color c = g.getColor();
    g.setColor(table.getGridColor());
    g.drawRect(cellRect.x,cellRect.y,cellRect.width-1,cellRect.height-1);
    g.setColor(c);
 
    cellRect.setBounds(cellRect.x + spacingWidth/2, cellRect.y + spacingHeight/2,
                       cellRect.width - spacingWidth, cellRect.height - spacingHeight);
 
    if (table.isEditing() && table.getEditingRow()==row &&
        table.getEditingColumn()==column) {
      Component component = table.getEditorComponent();
      component.setBounds(cellRect);
      component.validate();
    }
    else {
      TableCellRenderer renderer = table.getCellRenderer(row, column);
      Component component = table.prepareRenderer(renderer, row, column);

      if (component.getParent() == null) {
        rendererPane.add(component);
      }
      rendererPane.paintComponent(g, component, table, cellRect.x, cellRect.y,
                                  cellRect.width, cellRect.height, true);
    }
  }    
}

Embedding a JSpinner inside a JTable cell

Main.java:

import javax.swing.table.*;
import java.awt.event.*;
import javax.swing.*;
import java.awt.*;
  
public class JSpinnerTableExample extends JFrame {
 
  public JSpinnerTableExample(){
    super( "JSpinnerTable Example" );
    
    SpinnerNumberModel spinnerModel1 = new SpinnerNumberModel(10.0, -500.0, 500.0, .5);
    SpinnerDateModel spinnerModel2 = new SpinnerDateModel();
 
    DefaultTableModel dtm = new DefaultTableModel();
    dtm.setDataVector(new Object[][]{{ spinnerModel1, "JSpinner1" },
                                     { spinnerModel2, "JSpinner2" }},
                      new Object[]{"JSpinner","String"});
                     
    JTable table = new JTable(dtm);
    table.getColumn("JSpinner").setCellRenderer(new SpinnerRenderer());
    table.getColumn("JSpinner").setCellEditor(new SpinnerEditor());
 
    table.setRowHeight(20);
    JScrollPane scroll = new JScrollPane(table);
    getContentPane().add(scroll);
 
    setSize( 400, 100 );
    setVisible(true);
  }
 
  public static void main(String[] args) {
    JSpinnerTableExample frame = new JSpinnerTableExample();
    frame.addWindowListener(new WindowAdapter() {
      public void windowClosing(WindowEvent e) {
        System.exit(0);
      }
    });
  }
}
 
class SpinnerRenderer extends JSpinner implements TableCellRenderer {
   public SpinnerRenderer() {
      setOpaque(true);
   }
  
   public Component getTableCellRendererComponent(JTable table, Object value,
                    boolean isSelected, boolean hasFocus, int row, int column) {
      setModel((SpinnerModel) value);
  
      return this;
   }
}
  
class SpinnerEditor extends AbstractCellEditor implements TableCellEditor {
   protected JSpinner spinner;
  
   public SpinnerEditor() {
      spinner = new JSpinner();
   }
 
   public Component getTableCellEditorComponent(JTable table, Object value,
                    boolean isSelected, int row, int column) {
      spinner.setModel((SpinnerModel) value);
 
      return spinner;
   }
 
   public Object getCellEditorValue() {
      SpinnerModel sm = spinner.getModel();
      return sm;
   }
}

Adding a background image to a JTree that does not scroll

(1.3+)

Main.java:

import javax.swing.*;
import javax.swing.tree.*;
import javax.swing.event.*;
import java.awt.*;
import java.net.*;
import java.awt.event.*;
 
public class Main extends JFrame
{
   public Main() {
      DefaultMutableTreeNode root = new DefaultMutableTreeNode("Root");
      for (int i=0; i<100; i++) {
         DefaultMutableTreeNode child = new DefaultMutableTreeNode("Child " + (i+1));
         root.add(child);
      }
      JTree tree = new JTree(root);
 
      tree.setOpaque( false );
  
 
      DefaultTreeCellRenderer cr = new DefaultTreeCellRenderer();
      cr.setOpaque(false);
      cr.setBackground(new Color(0, 0, 0, 0));  
      cr.setBackgroundNonSelectionColor(null);
      tree.setCellRenderer(cr);
 
      ImageJScrollPane scrollpane = new ImageJScrollPane(tree);
      scrollpane.setBackgroundImage(new ImageIcon("mong.jpg"));
 
      getContentPane().add(scrollpane);
 
      addWindowListener(new WindowAdapter() {
         public void windowClosing(WindowEvent we) {
            System.exit(0);
         }
      });
   }
 
   public static void main(String []args) {
      Main main = new Main();
      main.setSize(400, 400);
      main.setVisible(true);
   }
}
 
class ImageJScrollPane extends JScrollPane
{
   private ImageIcon image = null;
 
   public ImageJScrollPane() {
      this(null, VERTICAL_SCROLLBAR_AS_NEEDED, HORIZONTAL_SCROLLBAR_AS_NEEDED);
   }
 
   public ImageJScrollPane(Component view) {
      this(view, VERTICAL_SCROLLBAR_AS_NEEDED, HORIZONTAL_SCROLLBAR_AS_NEEDED);
   }
 
   public ImageJScrollPane(Component view, int vsbPolicy, int hsbPolicy) {
      super(view, vsbPolicy, hsbPolicy);
      if (view instanceof JComponent) {
         ((JComponent) view).setOpaque(false);
      }
      setOpaque(false);
      getViewport().setOpaque(false);
      getViewport().setScrollMode(JViewport.BLIT_SCROLL_MODE);
   }
 
   public ImageJScrollPane(int vsbPolicy, int hsbPolicy) {
      this(null, vsbPolicy, hsbPolicy);
   }
 
   public void setBackgroundImage(ImageIcon image) {
      this.image = image;
   }
 
   public void paint(Graphics g) {
      if (image != null) {
         Rectangle rect = getViewport().getViewRect();
         for (int x=0; x<rect.width; x+=image.getIconWidth()) {
            for (int y=0; y<rect.height; y+=image.getIconHeight()) {
               g.drawImage(image.getImage(), x, y, null, null);
            }
         }
         super.paint(g);
      }
 
   }
}

Image used:

Using Apache’s Xerces SAX parser

Download the Xerces Java parser at http://xml.apache.org/xerces2-j/index.html. Adjust your classpath and specify that you want to use the Xerces parser.

Programmatically:

import org.xml.sax.helpers.*;
import javax.xml.parsers.*;
import org.xml.sax.*;
import java.io.*;
 
public class Main 
{
   public static void main(String []args) {
      try {
         SAXParserFactory factory = new org.apache.xerces.jaxp.SAXParserFactoryImpl();    
         SAXParser parser = factory.newSAXParser();
 
         InputSource is = new InputSource(new FileReader("example.xml"));
         parser.parse(is, new DefaultHandler());
      }
      catch(ParserConfigurationException e) {
         e.printStackTrace();
      }
      catch(SAXException e) {
         e.printStackTrace();
      }
      catch(IOException e) {
         e.printStackTrace();
      }        
   }
}

Declaratively:

   java -Djavax.xml.parsers.SAXParserFactory=org.apache.xerces.jaxp.SAXParserFactoryImpl Main

Traversing a DOM tree using a TreeWalker in Java

(DOM Level 2!) TreeWalker allows you to navigate a DOM tree. You can specify the view on the tree with whatToShow flags and a NodeFilter (for an example on using a NodeFilter, check out How do I traverse a DOM tree using a NodeIterator).

Once you have a TreeWalker instance, you can navigate through the structure using various methods that speak for themselves. Check out the API docs for more information: TreeWalker, NodeFilter.

customers.xml (!!remove the space between ? and xml):

<? xml version="1.0" encoding="UTF-8"?>
<customers>
   <customer id="C12345">
      <name>Joris Van den Bogaert</name>
      <address>
         <addressline>Handelskaai 3</addressline>
         <zip>1000</zip>
         <location>Brussels</location>
         <country>BELGIUM</country>
      </address>
   </customer>
   <customer id="C23495">
      <name>John Doe</name>
      <address>
         <addressline>5, S 5th Ave.</addressline>
         <zip>59715</zip>
         <location>Bozeman, MT</location>
         <country>US</country>
      </address>
   </customer>
   <customer id="C03429">
      <name>John Babcock</name>
      <address>
         <addressline>73, Broad street</addressline>
         <zip>06418</zip>
         <location>Chester, CT</location>
         <country>US</country>
      </address>
   </customer>
   <customer id="C12345">
      <name>Dominique Bodard</name>
      <address>
         <addressline>21-23, Rue de Madrid</addressline>
         <zip>75008</zip>
         <location>Paris</location>
         <country>FRANCE</country>
      </address>
   </customer>
</customers>

Main.java:

import org.w3c.dom.*;
import org.w3c.dom.traversal.*;
  
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.DocumentBuilder;
 
import java.io.*;
   
public class Main
{
   public static void main(String []args) {
      Document doc;
  
      try {
         DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
         DocumentBuilder db = dbf.newDocumentBuilder();
         doc = db.parse(new File("customers.xml")); 
 
         if (!doc.isSupported("Traversal", "2.0")) {
            System.out.println("Traversal not supported in your parser version");
            System.exit(1);
         }
 
         DocumentTraversal dt = (DocumentTraversal) doc;
         TreeWalker walker = dt.createTreeWalker(doc, 
                                                 NodeFilter.SHOW_ALL, 
                                                 null, 
                                                 true);
  
         outputNode(walker.getCurrentNode());  // #document
         outputNode(walker.nextNode());        // customers
         outputNode(walker.nextNode());        // #text
         outputNode(walker.nextNode());        // customer
         outputNode(walker.nextNode());        // #text
         outputNode(walker.nextNode());        // name
         outputNode(walker.lastChild());       // #text [Joris Van den Bogaert]
         outputNode(walker.nextNode());        // #text
         outputNode(walker.nextNode());        // address
         outputNode(walker.previousSibling()); // #text
         outputNode(walker.nextNode());        // address
         outputNode(walker.nextNode());        // #text
         outputNode(walker.parentNode());      // address
         outputNode(walker.nextNode());        // #text
         outputNode(walker.nextSibling());     // addressline
         outputNode(walker.nextNode());        // #text [Handelskaai 3]
         outputNode(walker.previousNode());    // addressline
         outputNode(walker.parentNode());      // address
      }
      catch(Exception e) {
         e.printStackTrace();
      }
   } 
 
   public static void outputNode(Node node) {
      System.out.print(node.getNodeName());
      if (node.getNodeType() == Node.TEXT_NODE && !node.getNodeValue().trim().equals("")) {
         System.out.print(" [" + node.getNodeValue() + "]");
      }
      System.out.println();
   } 
}

outputs:

#document
customers
#text
customer
#text
name
#text [Joris Van den Bogaert]
#text
address
#text
address
#text
address
#text
addressline
#text [Handelskaai 3]
addressline
address

Update rows from a database table

Check out the MySQL syntax for UPDATE here.

Here’s an example that modifes a value in the customer table. You need to create a Statement object from a Connection and invoke executeUpdate on it, passing it the SQL UPDATE command. It returns a ResultSet containing the database rows that match your query. You can then iterate over the rows with the next method. The first call to next will position the “cursor” to the first row. You can get a particular column in that row with the getXXX methods, specifying either the column index or the column name. Make sure the database column type and the resulting variable type match, or a proper conversion is done. If types don’t match, a Bad format SQLException is thrown.

Main.java:

import java.util.*;
import java.sql.*;
  
public class Main {
   public static void main(String []args) {
      try {
         Database db = new Database("org.gjt.mm.mysql.Driver",
                                    "jdbc:mysql://192.168.0.1/esus",
                                    "joris",
                                    "mypass");
         Connection con = db.getConnection();
         CustomerDAO custDAO = new CustomerDAO(con);
 
         printCollection(custDAO.getAllRows()); 
 
         Customer cust = custDAO.getCustomer("Joris Van den Bogaert");
         if (cust != null) {
            cust.setEmail("joris_vandenbogaert1@yahoo.com");
            custDAO.updateEmail(cust);
         }
  
         System.out.println();
         printCollection(custDAO.getAllRows()); 
         db.close();
      }
      catch(DatabaseException e) {
         e.printStackTrace();
      }
   }
 
   public static void printCollection(Collection c) {
      Iterator iter = c.iterator();
      while (iter.hasNext()) {
         System.out.println(iter.next());
      }
   }
}
 
class Customer
{
   private String name;
   private String email;
 
   public Customer() { }
 
   public Customer(String name, String email) {
      setName(name);
      setEmail(email);
   }
  
   public void setName(String name) {
      this.name = name;
   }
 
   public void setEmail(String email) {
      this.email = email;
   }
 
   public String getName() {
      return name;
   }
 
   public String getEmail() {
      return email;
   }
 
   public String toString() {
      return "Customer [name=" + getName() + ", email=" + getEmail() + "]";
   }
}
 
class Database
{
   Connection connection = null;
  
   public Database(String driver, String url, String user, String pass) 
                      throws DatabaseException 
   {
      try {
         Class.forName(driver).newInstance();
 
         connection = DriverManager.getConnection(url, user, pass);
      }
      catch(Exception e) {
         throw new DatabaseException(e.getMessage());
      }
   }
 
   public Connection getConnection() {
      return connection;
   }
 
   public void close() throws DatabaseException {
      try {
         connection.close();
      }
      catch(Exception e) {
         throw new DatabaseException(e.getMessage());
      }
   } 
}   
 
class DatabaseException extends Exception {
   public DatabaseException() {
   }
 
   public DatabaseException(String message) {
      super(message);
   }
}
 
class CustomerDAO 
{
   Connection connection = null;
 
   public CustomerDAO(Connection connection) {
      this.connection = connection;
   }
 
   public void updateEmail(Customer cust) throws DatabaseException {
      try {
         Statement stmt = connection.createStatement();
 
         stmt.executeUpdate("UPDATE customers SET email = '" + cust.getEmail() + "' " +
                            "WHERE name = '" + cust.getName() + "'");
         stmt.close();      
      }
      catch(SQLException e) {
         throw new DatabaseException(e.getMessage());
      }
   }
 
   public Customer getCustomer(String name) throws DatabaseException {
      try {
         Statement stmt = connection.createStatement();
         ResultSet rs = stmt.executeQuery("SELECT * FROM customers " +
                                          "WHERE name='" + name + "'");
         if (rs.next()) {
            Customer cust = new Customer();
            cust.setName(rs.getString("name"));
            cust.setEmail(rs.getString("email"));
            return cust;
         }
      }
      catch(SQLException e) {
         throw new DatabaseException(e.getMessage());
      }
 
      return null;
   } 
 
   public Collection getAllRows() throws DatabaseException {
      try {
         ArrayList al = new ArrayList();
 
         Statement stmt = connection.createStatement();
         ResultSet rs = stmt.executeQuery("SELECT * FROM customers");
         while (rs.next()) {
            Customer cust = new Customer();
            cust.setName(""+rs.getString("name"));
            cust.setEmail(rs.getString("email"));
            al.add(cust);
         }
         
         stmt.close();
 
         return al;
      }
      catch(SQLException e) {
         throw new DatabaseException(e.getMessage());
      }
   }
}

outputs:

Customer [name=Joris Van den Bogaert, email=joris1@esus.com]
Customer [name=Alicia Kolesnikova, email=alicia1@esus.com]

Customer [name=Joris Van den Bogaert, email=joris_vandenbogaert1@yahoo.com]
Customer [name=Alicia Kolesnikova, email=alicia1@esus.com]

Returning an image stored in mysql with a servlet

To answer this, I created a table images in a test database and stored the esus logo in it.

mysql> create table images (imageuid int(10) not null auto_increment, 
name varchar(30), data blob, length int(6), primary key(imageuid));
Query OK, 0 rows affected (0.12 sec) 
mysql> desc images;
+----------+-------------+------+-----+---------+----------------+
| Field    | Type        | Null | Key | Default | Extra          |
+----------+-------------+------+-----+---------+----------------+
| imageuid | int(10)     |      | PRI | NULL    | auto_increment |
| name     | varchar(30) | YES  |     | NULL    |                |
| length   | int(6)      | YES  |     | NULL    |                |
| data     | blob        | YES  |     | NULL    |                |
+----------+-------------+------+-----+---------+----------------+

To save an image in this table, use the following code and specify the image at command line. Use a JPG image, as the MIME content type for the servlet we’ll write will be image/jpeg.

Main.java:

import java.util.*;
import java.text.*;
import java.sql.*;
import java.io.*;  
 
public class Main {
   public static void main(String []args) throws Exception {
      try {
         if (args.length != 1) {
            System.out.println("Usage: java Main <img>");
            System.exit(1);
         }
 
         Class.forName("org.gjt.mm.mysql.Driver").newInstance();
         Connection conn = DriverManager.getConnection("jdbc:mysql://localhost/testdb", 
                                                       "",
                                                       "");
 
         File file = new File(args[0]);
         FileInputStream fis=new FileInputStream(file);
         ByteArrayOutputStream baos = new ByteArrayOutputStream();
         byte buf[]=new byte[1024];
         int length=-1;
         while((length=fis.read(buf))!=-1) {
            baos.write(buf,0,length);
         }
 
         PreparedStatement insertStmt = conn.prepareStatement(
                                       "INSERT INTO images (name, length, data) " +
                                       "VALUES (?, ?, ?)");
         insertStmt.setString(1, file.getName());
         insertStmt.setInt(2, (int) file.length());
         insertStmt.setBytes(3, baos.toByteArray());
         insertStmt.execute();
 
         fis.close();
         baos.close();
      }
      catch(Exception e) {
         e.printStackTrace();
      }
   } 
}

The servlet that delivers the image to the browser looks just like any other one, except that the MIME content-type attribute is set to image/jpeg (use image/gif for GIF files). The rest of the code handles the reading of the image from the mysql table given its unique index.

Servlet GetImage.java:

import javax.servlet.*;
import javax.servlet.http.*;
import java.util.*;
import java.sql.*;
import java.io.*;
 
public class GetImage extends HttpServlet {
 
   public void doGet(
       HttpServletRequest request,
       HttpServletResponse response)
         throws ServletException, IOException {
 
     response.setContentType("image/jpeg");
 
     ServletOutputStream sos = response.getOutputStream();
 
     int imageuid = Integer.parseInt(getValues(request, "imageuid"));
     byte[] buf = getImageFromDB(imageuid);
 
     sos.write(buf);
 
     sos.flush();
  }
 
   public byte[] getImageFromDB(int imageuid) {
      byte[] buffer = null;
 
      try {
         Class.forName("org.gjt.mm.mysql.Driver").newInstance();
         Connection conn = DriverManager.getConnection("jdbc:mysql://localhost/testdb", 
                                                       "",
                                                       "");
 
         Statement stmt = conn.createStatement();
         ResultSet rs = stmt.executeQuery("SELECT name, length, data FROM images " +
                                          "where imageuid = " + imageuid);
      
         if (rs.next()) {
            String name = rs.getString("name");
            int length = rs.getInt("length");
            buffer = rs.getBytes("data");
         }
      }
      catch(Exception e) {
         e.printStackTrace();
      }
 
      return buffer;
   }
 
   public String getValues(HttpServletRequest request, String name) {
      String retVal = "";
 
      String values[] = request.getParameterValues(name);
      if (values == null) {
      }
      else if (values.length == 1) {
         retVal = values[0];
      }
      else {
         for (int i=0; i<values.length; i++) {
            retVal += values[i] + ", ";
         }
      }
 
      return retVal;
   }
}

You can now use the reference to this servlet in an img src HTML tag:

<html>
<body>
<center><img src="http://localhost:8080/servlet/GetImage?imageuid=1"></center>
</body>
</html>