用html制作JEditorPane将正确格式的文本放入剪贴板

萧心水

2023-03-14

问题内容：

我有这段代码来演示问题：

public static void main(String[] args) {
    JFrame frame = new JFrame();
    frame.getContentPane().add(new JEditorPane("text/html", "Hello cruel world<br>\n<font color=red>Goodbye cruel world</font><br>\n<br>\nHello again<br>\n"));
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.pack();
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
}

如果您选择了应用启动后出现在框架中的所有文本，则可以将其复制并粘贴到MS
Word，Apple的Pages或Mail中，并且文本的格式正确。但是，如果将其粘贴到纯文本编辑器（如TextEdit，Smultron或Skype聊天窗口）中，则所有粘贴的内容都在一行上。

如何使复制到剪贴板的文本能够粘贴保留的换行符？

我在Mac OS X 10.7上运行我的代码

问题答案：

没有得到答案后，我袖手旁观，做了很多研究和学习。解决方案是为组件创建自定义TransferHandler，然后手动处理HTML文本。解决所有这些问题并不容易，这可以解释我得到的零答案。

这是一个可行的解决方案：

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);
    }
}

用html制作JEditorPane将正确格式的文本放入剪贴板

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