使用html制作JEditorPane，将格式正确的文本放入剪贴板

clipboard macos java swing jeditorpane

2022-09-03 13:14:35

我有这个代码来演示这个问题：

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);
}

如果您在应用程序启动后选择框架中显示的所有文本，则可以将其复制并粘贴到MS Word，Apple的Pages或Mail中，并且文本格式正确。但是，如果您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并保留换行符？

我在 Mac OS X 10.7 上运行代码

答案 1

在没有得到答案后，我卷起袖子，做了很多研究和学习。解决方案是为组件创建自定义的 TransferHandler，然后手动调整 HTML 文本。要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);
    }
}

答案 2

注意：这不是对问题的回答，只是一个带有代码的评论，由@Thorn回答，与安全限制有关

在具有默认权限的 webstartables 中（即，无 ;-）您可以在运行时向 SecurityManager 请求剪贴板服务：它将弹出一个对话框，要求用户允许（或禁止）复制。这样，您就可以替换文本Component中的默认复制操作。在 SwingX 演示中，我们支持通过以下方式从源区域粘贴代码：

/**
 * Replaces the editor's default copy action in security restricted
 * environments with one messaging the ClipboardService. Does nothing 
 * if not restricted.
 * 
 * @param editor the editor to replace 
 */
public static void replaceCopyAction(final JEditorPane editor) {
    if (!isRestricted()) return;
    Action safeCopy = new AbstractAction() {

        @Override
        public void actionPerformed(ActionEvent e) {
            try {
                ClipboardService cs = (ClipboardService)ServiceManager.lookup
                    ("javax.jnlp.ClipboardService");
                StringSelection transferable = new StringSelection(editor.getSelectedText());
                cs.setContents(transferable);
            } catch (Exception e1) {
                // do nothing
            }
        }
    };
    editor.getActionMap().put(DefaultEditorKit.copyAction, safeCopy);
}

private static boolean isRestricted() {
    SecurityManager manager = System.getSecurityManager();
    if (manager == null) return false;
    try {
        manager.checkSystemClipboardAccess();
        return false;
    } catch (SecurityException e) {
        // nothing to do - not allowed to access
    }
    return true;
}