After getting no answers, I rolled up my sleeves and did a lot of research and learning. The solution is to make a custom TransferHandler for the component, and massage the HTML text manually. It wasn't easy to work all this out, which could account for the zero answers I got.
Here's a working solution:
import javax.swing.*;
import javax.swing.text.MutableAttributeSet;
import javax.swing.text.html.HTML;
import javax.swing.text.html.HTMLEditorKit;
import javax.swing.text.html.parser.ParserDelegator;
import java.awt.datatransfer.Clipboard;
import java.awt.datatransfer.DataFlavor;
import java.awt.datatransfer.Transferable;
import java.awt.datatransfer.UnsupportedFlavorException;
import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import java.util.ArrayList;
public class ScratchSpace {
public static void main(String[] args) {
final JFrame frame = new JFrame();
final JEditorPane pane = new JEditorPane("text/html", "<html><font color=red>Hello</font><br>\u2663<br>World");
pane.setTransferHandler(new MyTransferHandler());
frame.getContentPane().add(pane);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
}
class MyTransferHandler extends TransferHandler {
protected Transferable createTransferable(JComponent c) {
final JEditorPane pane = (JEditorPane) c;
final String htmlText = pane.getText();
final String plainText = extractText(new StringReader(htmlText));
return new MyTransferable(plainText, htmlText);
}
public String extractText(Reader reader) {
final ArrayList<String> list = new ArrayList<String>();
HTMLEditorKit.ParserCallback parserCallback = new HTMLEditorKit.ParserCallback() {
public void handleText(final char[] data, final int pos) {
list.add(new String(data));
}
public void handleStartTag(HTML.Tag tag, MutableAttributeSet attribute, int pos) {
}
public void handleEndTag(HTML.Tag t, final int pos) {
}
public void handleSimpleTag(HTML.Tag t, MutableAttributeSet a, final int pos) {
if (t.equals(HTML.Tag.BR)) {
list.add("\n");
}
}
public void handleComment(final char[] data, final int pos) {
}
public void handleError(final String errMsg, final int pos) {
}
};
try {
new ParserDelegator().parse(reader, parserCallback, true);
} catch (IOException e) {
e.printStackTrace();
}
String result = "";
for (String s : list) {
result += s;
}
return result;
}
@Override
public void exportToClipboard(JComponent comp, Clipboard clip, int action) throws IllegalStateException {
if (action == COPY) {
clip.setContents(this.createTransferable(comp), null);
}
}
@Override
public int getSourceActions(JComponent c) {
return COPY;
}
}
class MyTransferable implements Transferable {
private static final DataFlavor[] supportedFlavors;
static {
try {
supportedFlavors = new DataFlavor[]{
new DataFlavor("text/html;class=java.lang.String"),
new DataFlavor("text/plain;class=java.lang.String")
};
} catch (ClassNotFoundException e) {
throw new ExceptionInInitializerError(e);
}
}
private final String plainData;
private final String htmlData;
public MyTransferable(String plainData, String htmlData) {
this.plainData = plainData;
this.htmlData = htmlData;
}
public DataFlavor[] getTransferDataFlavors() {
return supportedFlavors;
}
public boolean isDataFlavorSupported(DataFlavor flavor) {
for (DataFlavor supportedFlavor : supportedFlavors) {
if (supportedFlavor == flavor) {
return true;
}
}
return false;
}
public Object getTransferData(DataFlavor flavor) throws UnsupportedFlavorException, IOException {
if (flavor.equals(supportedFlavors[0])) {
return htmlData;
}
if (flavor.equals(supportedFlavors[1])) {
return plainData;
}
throw new UnsupportedFlavorException(flavor);
}
}
