此组件使用 EditorKit 的实现来完成其操作。对于给予它的各种内容，它能有效地将其形态变换为适当的文本编辑器种类。该编辑器在任意给定时间的内容类型都由当前已安装的 EditorKit 确定。如果将内容设置为新的 URL，则使用其类型来确定加载该内容所应使用的 EditorKit。
有多种方式可将内容加载到此组件中。
1. 可使用 setText 方法来初始化字符串组件。在这种情况下，将使用当前的 EditorKit，且此类型为期望的内容类型。
2. 可使用 read 方法来初始化 Reader 组件。注意，如果内容类型为 HTML，那么只有使用了 <base> 标记，或者设置了 HTMLDocument 上的 Base 属性时才能解析相关的引用（例如对于类似图像等内容）。在这种情况下，将使用当前的 EditorKit，且此类型为期望的内容类型。
3. 可使用 setPage 方法来初始化 URL 组件。在这种情况下，将根据该 URL 来确定内容类型，并且设置为该内容类型所注册的 EditorKit。
构造函数
JEditorPane()
创建一个新的 JEditorPane。
JEditorPane(String url)
根据包含 URL 规范的字符串创建一个 JEditorPane。
JEditorPane(String type, String text)
创建一个已初始化为给定文件的 JEditorPane。
JEditorPane(URL initialPage)
根据用作输入的指定 URL 创建一个 JEditorPane。
常用方法
addHyperlinkListener(HyperlinkListener listener)
为了通知所有的更改（例如选中和进入某个链接）而添加一个超链接侦听器。
getContentType()
获得设置此编辑器当前要处理的内容类型。
getEditorKit()
获取用于处理内容的、当前已安装的工具包。
getPage()
获得当前正在显示的 URL。
getPreferredSize()
返回该 JEditorPane 的首选大小。
getText()
根据此编辑器的内容类型返回此 TextComponent 中所包含的文本。
getStream(URL page)
获取给定 URL 的流，该 URL 是将要由 setPage 方法加载的。
scrollToReference(String reference)
将视图滚动到给定的参考位置（也就是正在显示的 URL 的 UL.getRef 方法所返回的值）。
setContentType(String type)
设置此编辑器所处理的内容类型。
setEditorKit(EditorKit kit)
设置当前为处理内容而安装的工具包。
setPage(String url)
设置当前要显示的 URL。
setPage(URL page)
设置当前要显示的 URL。
setText(String t)
将此 TextComponent 的文本设置为指定内容，预期以此编辑器的内容类型格式提供该内容。
import java.awt.*; import java.awt.event.*; import java.beans.*; import java.io.*; import java.net.*; import java.util.*; import javax.swing.*; import javax.swing.event.*; import javax.swing.tree.*; import javax.swing.text.*; import javax.swing.text.html.*; import javax.swing.text.rtf.*; public class EditorPaneExample19 extends JFrame { public EditorPaneExample19() { super("JEditorPane Example 19"); pane = new JEditorPane(); pane.setEditable(true); // Editable getContentPane().add(new JScrollPane(pane), "Center"); // Add a menu bar menuBar = new JMenuBar(); setJMenuBar(menuBar); // Populate it createMenuBar(); // Build the panel of controls JPanel panel = new JPanel(); panel.setLayout(new GridBagLayout()); GridBagConstraints c = new GridBagConstraints(); c.gridwidth = 1; c.gridheight = 1; c.anchor = GridBagConstraints.EAST; c.fill = GridBagConstraints.NONE; c.weightx = 0.0; c.weighty = 0.0; JLabel urlLabel = new JLabel("URL: ", JLabel.RIGHT); panel.add(urlLabel, c); JLabel loadingLabel = new JLabel("State: ", JLabel.RIGHT); c.gridy = 1; panel.add(loadingLabel, c); JLabel typeLabel = new JLabel("Type: ", JLabel.RIGHT); c.gridy = 2; panel.add(typeLabel, c); c.gridy = 3; panel.add(new JLabel(LOAD_TIME), c); c.gridy = 4; c.gridwidth = 2; c.weightx = 1.0; c.anchor = GridBagConstraints.WEST; onlineLoad = new JCheckBox("Online Load"); panel.add(onlineLoad, c); onlineLoad.setSelected(true); onlineLoad.setForeground(typeLabel.getForeground()); c.gridy = 5; c.gridwidth = 2; c.weightx = 1.0; c.anchor = GridBagConstraints.WEST; editableBox = new JCheckBox("Editable JEditorPane"); panel.add(editableBox, c); editableBox.setSelected(true); editableBox.setForeground(typeLabel.getForeground()); c.gridy = 6; c.weightx = 0.0; JButton saveButton = new JButton("Save"); panel.add(saveButton, c); saveButton.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent evt) { EditorKit kit = pane.getEditorKit(); try { if (kit instanceof RTFEditorKit) { kit.write(System.out, pane.getDocument(), 0, pane.getDocument().getLength()); System.out.flush(); } else { if (writer == null) { writer = new OutputStreamWriter(System.out); pane.write(writer); writer.flush(); } kit.write(writer, pane.getDocument(), 0, pane.getDocument().getLength()); writer.flush(); } } catch (Exception e) { System.out.println("Write failed"); } } }); c.gridx = 1; c.gridy = 0; c.weightx = 1.0; c.anchor = GridBagConstraints.EAST; c.fill = GridBagConstraints.HORIZONTAL; urlCombo = new JComboBox(); panel.add(urlCombo, c); urlCombo.setEditable(true); loadingState = new JLabel(spaces, JLabel.LEFT); loadingState.setForeground(Color.black); c.gridy = 1; panel.add(loadingState, c); loadedType = new JLabel(spaces, JLabel.LEFT); loadedType.setForeground(Color.black); c.gridy = 2; panel.add(loadedType, c); timeLabel = new JLabel(""); c.gridy = 3; panel.add(timeLabel, c); getContentPane().add(panel, "South"); // Register a custom EditorKit for HTML ClassLoader loader = getClass().getClassLoader(); if (loader != null) { // Java 2 JEditorPane.registerEditorKitForContentType("text/html", "AdvancedSwing.Chapter4.EnhancedHTMLEditorKit", loader); } else { // JDK 1.1 JEditorPane.registerEditorKitForContentType("text/html", "AdvancedSwing.Chapter4.EnhancedHTMLEditorKit"); } // Allocate the empty tree model DefaultMutableTreeNode emptyRootNode = new DefaultMutableTreeNode("Empty"); emptyModel = new DefaultTreeModel(emptyRootNode); // Create and place the heading tree tree = new JTree(emptyModel); tree.setPreferredSize(new Dimension(200, 200)); getContentPane().add(new JScrollPane(tree), "East"); // Change page based on combo selection urlCombo.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent evt) { if (populatingCombo == true) { return; } Object selection = urlCombo.getSelectedItem(); loadNewPage(selection); } }); // Change editability based on the checkbox editableBox.addActionListener(new ActionListener() { public void actionPerformed(ActionEvent evt) { pane.setEditable(editableBox.isSelected()); pane.revalidate(); pane.repaint(); } }); // Listen for page load to complete pane.addPropertyChangeListener(new PropertyChangeListener() { public void propertyChange(PropertyChangeEvent evt) { if (evt.getPropertyName().equals("page")) { loadComplete(); displayLoadTime(); populateCombo(findLinks(pane.getDocument(), null)); TreeNode node = buildHeadingTree(pane.getDocument()); tree.setModel(new DefaultTreeModel(node)); createMenuBar(); enableMenuBar(true); getRootPane().revalidate(); enableInput(); loadingPage = false; } } }); // Listener for tree selection tree.addTreeSelectionListener(new TreeSelectionListener() { public void valueChanged(TreeSelectionEvent evt) { TreePath path = evt.getNewLeadSelectionPath(); if (path != null) { DefaultMutableTreeNode node = (DefaultMutableTreeNode)path.getLastPathComponent(); Object userObject = node.getUserObject(); if (userObject instanceof Heading) { Heading heading = (Heading)userObject; try { Rectangle textRect = pane.modelToView(heading.getOffset()); textRect.y += 3 * textRect.height; pane.scrollRectToVisible(textRect); } catch (BadLocationException e) { } } } } }); // Listener for hypertext events pane.addHyperlinkListener(new HyperlinkListener() { public void hyperlinkUpdate(HyperlinkEvent evt) { // Ignore hyperlink events if the frame is busy if (loadingPage == true) { return; } if (evt.getEventType() == HyperlinkEvent.EventType.ACTIVATED) { JEditorPane sp = (JEditorPane)evt.getSource(); if (evt instanceof HTMLFrameHyperlinkEvent) { HTMLDocument doc = (HTMLDocument)sp.getDocument(); doc.processHTMLFrameHyperlinkEvent((HTMLFrameHyperlinkEvent)evt); } else { loadNewPage(evt.getURL()); } } else if (evt.getEventType() == HyperlinkEvent.EventType.ENTERED) { pane.setCursor(handCursor); } else if (evt.getEventType() == HyperlinkEvent.EventType.EXITED) { pane.setCursor(defaultCursor); } } }); } public void loadNewPage(Object page) { try { loadingPage = true; // Check if the new page and the old // page are the same. URL url; if (page instanceof URL) { url = (URL)page; } else { url = new URL((String)page); } urlCombo.setSelectedItem(page); URL loadedURL = pane.getPage(); if (loadedURL != null && loadedURL.sameFile(url)) { return; } enableMenuBar(false); urlCombo.paintImmediately(0, 0, menuBar.getSize().width, menuBar.getSize().height); // Try to display the page urlCombo.setEnabled(false); // Disable input urlCombo.paintImmediately(0, 0, urlCombo.getSize().width, urlCombo.getSize().height); setCursor(waitCursor); // Busy cursor loadingState.setText("Loading..."); loadingState.paintImmediately(0, 0, loadingState.getSize().width, loadingState.getSize().height); loadedType.setText(""); loadedType.paintImmediately(0, 0, loadedType.getSize().width, loadedType.getSize().height); timeLabel.setText(""); timeLabel.paintImmediately(0, 0, timeLabel.getSize().width, timeLabel.getSize().height); // Display an empty tree while loading tree.setModel(emptyModel); tree.paintImmediately(0, 0, tree.getSize().width, tree.getSize().height); startTime = System.currentTimeMillis(); // Choose the loading method if (onlineLoad.isSelected()) { // Usual load via setPage pane.setPage(url); loadedType.setText(pane.getContentType()); } else { pane.setContentType("text/html"); loadedType.setText(pane.getContentType()); if (loader == null) { loader = new HTMLDocumentLoader(); } HTMLDocument doc = loader.loadDocument(url); loadComplete(); pane.setDocument(doc); displayLoadTime(); populateCombo(findLinks(doc, null)); TreeNode node = buildHeadingTree(doc); tree.setModel(new DefaultTreeModel(node)); createMenuBar(); enableMenuBar(true); getRootPane().revalidate(); enableInput(); loadingPage = false; } } catch (Exception e) { System.out.println(e); JOptionPane.showMessageDialog(pane, new String[] { "Unable to open file", page.toString() }, "File Open Error", JOptionPane.ERROR_MESSAGE); loadingState.setText("Failed"); enableMenuBar(true); enableInput(); loadingPage = false; } } public void loadComplete() { loadingState.setText("Page loaded."); } public void enableInput() { urlCombo.setEnabled(true); // Allow entry of new URL setCursor(defaultCursor); pane.setCursor(defaultCursor); } public void displayLoadTime() { double loadingTime = ((double)(System.currentTimeMillis() - startTime))/1000d; timeLabel.setText(loadingTime + " seconds"); } public void populateCombo(URL[] urls) { // Save existing selection Object o = urlCombo.getSelectedItem(); populatingCombo = true; urlCombo.setModel(new DefaultComboBoxModel(urls)); // Restore original selection urlCombo.setSelectedItem(o); populatingCombo = false; } public void enableMenuBar(boolean cond) { int count = menuBar.getMenuCount(); for (int i = 0; i < count; i++) { menuBar.getMenu(i).setEnabled(cond); } } public void createMenuBar() { // Remove the existing menu items int count = menuBar.getMenuCount(); for (int i = 0; i < count; i++) { menuBar.remove(menuBar.getMenu(0)); } // Build the new menu. Action[] actions = pane.getActions(); Hashtable actionHash = new Hashtable(); count = actions.length; for (int i = 0; i < count; i++) { actionHash.put(actions[i].getValue(Action.NAME), actions[i]); } // Add the font menu JMenu menu = MenuBuilder.buildMenu("Font", fontSpec, actionHash); if (menu != null) { menuBar.add(menu); } // Add the alignment menu menu = MenuBuilder.buildMenu("Align", alignSpec, actionHash); if (menu != null) { menuBar.add(menu); } // Add the HTML menu menu = MenuBuilder.buildMenu("HTML", htmlSpec, actionHash); if (menu != null) { menuBar.add(menu); } } public URL[] findLinks(Document doc, String protocol) { Vector links = new Vector(); Vector urlNames = new Vector(); URL baseURL = (URL)doc.getProperty(Document.StreamDescriptionProperty); if (doc instanceof HTMLDocument) { Element elem = doc.getDefaultRootElement(); ElementIterator iterator = new ElementIterator(elem); while ((elem = iterator.next()) != null) { AttributeSet attrs = elem.getAttributes(); Object link = attrs.getAttribute(HTML.Tag.A); if (link instanceof AttributeSet) { Object linkAttr = ((AttributeSet)link).getAttribute(HTML.Attribute.HREF); if (linkAttr instanceof String) { try { URL linkURL = new URL(baseURL, (String)linkAttr); if (protocol == null || protocol.equalsIgnoreCase(linkURL.getProtocol())) { String linkURLName = linkURL.toString(); if (urlNames.contains(linkURLName) == false) { urlNames.addElement(linkURLName); links.addElement(linkURL); } } } catch (MalformedURLException e) { // Ignore invalid links } } } } } URL[] urls = new URL[links.size()]; links.copyInto(urls); links.removeAllElements(); urlNames.removeAllElements(); return urls; } public TreeNode buildHeadingTree(Document doc) { String title = (String)doc.getProperty(Document.TitleProperty); if (title == null) { title = "[No title]"; } Heading rootHeading = new Heading(title, 0, 0); DefaultMutableTreeNode rootNode = new DefaultMutableTreeNode(rootHeading); DefaultMutableTreeNode lastNode[] = new DefaultMutableTreeNode[7]; int lastLevel = 0; lastNode[lastLevel] = rootNode; if (doc instanceof HTMLDocument) { Element elem = doc.getDefaultRootElement(); ElementIterator iterator = new ElementIterator(elem); Heading heading; while ((heading = getNextHeading(doc, iterator)) != null) { // Add the node to the tree DefaultMutableTreeNode hNode = new DefaultMutableTreeNode(heading); int level = heading.getLevel(); if (level > lastLevel) { for (int i = lastLevel + 1; i < level; i++) { lastNode[i] = null; } lastNode[lastLevel].add(hNode); } else { int prevLevel = level - 1; while (prevLevel >= 0) { if (lastNode[prevLevel] != null) { break; } lastNode[prevLevel] = null; prevLevel--; } lastNode[prevLevel].add(hNode); } lastNode[level] = hNode; lastLevel = level; } } return rootNode; } public Heading getNextHeading(Document doc, ElementIterator iter) { Element elem; while ((elem = iter.next()) != null) { AttributeSet attrs = elem.getAttributes(); Object type = attrs.getAttribute(StyleConstants.NameAttribute); int level = getHeadingLevel(type); if (level > 0) { // It is a heading - get the text String headingText = ""; int count = elem.getElementCount(); for (int i = 0; i < count; i++) { Element child = elem.getElement(i); AttributeSet cattrs = child.getAttributes(); if (cattrs.getAttribute(StyleConstants.NameAttribute) == HTML.Tag.CONTENT) { try { int offset = child.getStartOffset(); headingText += doc.getText(offset, child.getEndOffset() - offset); } catch (BadLocationException e) { } } } headingText = headingText.trim(); return new Heading(headingText, level, elem.getStartOffset()); } } return null; } public int getHeadingLevel(Object type) { if (type instanceof HTML.Tag) { if (type == HTML.Tag.H1) { return 1; } if (type == HTML.Tag.H2) { return 2; } if (type == HTML.Tag.H3) { return 3; } if (type == HTML.Tag.H4) { return 4; } if (type == HTML.Tag.H5) { return 5; } if (type == HTML.Tag.H6) { return 6; } } return -1; } static class Heading { public Heading(String text, int level, int offset) { this.text = text; this.level = level; this.offset = offset; } public String getText() { return text; } public int getOffset() { return offset; } public int getLevel() { return level; } public String toString() { return text; } protected String text; protected int level; protected int offset; } public JEditorPane getEditorPane() { return pane; } public static void main(String[] args) { try { UIManager.setLookAndFeel("com.sun.java.swing.plaf.windows.WindowsLookAndFeel"); } catch (Exception evt) {} JFrame f = new EditorPaneExample19(); f.addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent evt) { System.exit(0); } }); f.setSize(500, 400); f.setVisible(true); } private static final String spaces = " "; private static final String LOAD_TIME = "Load time: "; private HTMLDocumentLoader loader; private JEditorPane pane; private JLabel loadingState; private JLabel loadedType; private JLabel timeLabel; private JComboBox urlCombo; private JCheckBox onlineLoad; private JCheckBox editableBox; private JTree tree; private TreeModel emptyModel; private JMenuBar menuBar; private long startTime; private boolean populatingCombo; private boolean loadingPage; private static final Cursor waitCursor = Cursor.getPredefinedCursor(Cursor.WAIT_CURSOR); private static final Cursor defaultCursor = Cursor.getPredefinedCursor(Cursor.DEFAULT_CURSOR); private static final Cursor handCursor = Cursor.getPredefinedCursor(Cursor.HAND_CURSOR); private OutputStreamWriter writer; private static MenuSpec[] sizeSpec = new MenuSpec[] { new MenuSpec("Size 8", "font-size-8"), new MenuSpec("Size 10", "font-size-10"), new MenuSpec("Size 12", "font-size-12"), new MenuSpec("Size 14", "font-size-14"), new MenuSpec("Size 16", "font-size-16"), new MenuSpec("Size 18", "font-size-18"), new MenuSpec("Size 24", "font-size-24"), new MenuSpec("Size 36", "font-size-36"), new MenuSpec("Size 48", "font-size-48") }; private static MenuSpec[] familySpec = new MenuSpec[] { new MenuSpec("Sans Serif", "font-family-SansSerif"), new MenuSpec("Monospaced", "font-family-Monospaced"), new MenuSpec("Serif", "font-family-Serif") }; private static MenuSpec[] styleSpec = new MenuSpec[] { new MenuSpec("Bold", "font-bold"), new MenuSpec("Italics", "font-italic"), new MenuSpec("Underline", "font-underline") }; // Menu definitions for fonts private static MenuSpec[] fontSpec = new MenuSpec[] { new MenuSpec("Size", sizeSpec), new MenuSpec("Family", familySpec), new MenuSpec("Style", styleSpec) }; // Alignment private static MenuSpec[] alignSpec = new MenuSpec[] { new MenuSpec("Left", "left-justify"), new MenuSpec("Center", "center-justify"), new MenuSpec("Right", "right-justify") }; // HTML menu private static MenuSpec[] headingSpec = new MenuSpec[] { new MenuSpec("Heading 1", "Heading 1"), new MenuSpec("Heading 2", "Heading 2") }; private static MenuSpec[] htmlSpec = new MenuSpec[] { new MenuSpec("Table", "InsertTable"), new MenuSpec("Table Row", "InsertTableRow"), new MenuSpec("Table Cell", "InsertTableDataCell"), new MenuSpec("Unordered List", "InsertUnorderedList"), new MenuSpec("Unordered List Item", "InsertUnorderedListItem"), new MenuSpec("Ordered List", "InsertOrderedList"), new MenuSpec("Ordered List Item", "InsertOrderedListItem"), new MenuSpec("Preformatted Paragraph", "InsertPre"), new MenuSpec("Horizontal Rule", "InsertHR"), new MenuSpec("Headings", headingSpec) }; } class MenuSpec { public MenuSpec(String name, MenuSpec[] subMenus) { this.name = name; this.subMenus = subMenus; } public MenuSpec(String name, String actionName) { this.name = name; this.actionName = actionName; } public MenuSpec(String name, Action action) { this.name = name; this.action = action; } public boolean isSubMenu() { return subMenus != null; } public boolean isAction() { return action != null; } public String getName() { return name; } public MenuSpec[] getSubMenus() { return subMenus; } public String getActionName() { return actionName; } public Action getAction() { return action; } private String name; private String actionName; private Action action; private MenuSpec[] subMenus; } class HTMLDocumentLoader { public HTMLDocument loadDocument(HTMLDocument doc, URL url, String charSet) throws IOException { doc.putProperty(Document.StreamDescriptionProperty, url); /* * This loop allows the document read to be retried if the character * encoding changes during processing. */ InputStream in = null; boolean ignoreCharSet = false; for (;;) { try { // Remove any document content doc.remove(0, doc.getLength()); URLConnection urlc = url.openConnection(); in = urlc.getInputStream(); Reader reader = (charSet == null) ? new InputStreamReader(in) : new InputStreamReader(in, charSet); HTMLEditorKit.Parser parser = getParser(); HTMLEditorKit.ParserCallback htmlReader = getParserCallback(doc); parser.parse(reader, htmlReader, ignoreCharSet); htmlReader.flush(); // All done break; } catch (BadLocationException ex) { // Should not happen - throw an IOException throw new IOException(ex.getMessage()); } catch (ChangedCharSetException e) { // The character set has changed - restart charSet = getNewCharSet(e); // Prevent recursion by suppressing further exceptions ignoreCharSet = true; // Close original input stream in.close(); // Continue the loop to read with the correct encoding } } return doc; } public HTMLDocument loadDocument(URL url, String charSet) throws IOException { return loadDocument((HTMLDocument) kit.createDefaultDocument(), url, charSet); } public HTMLDocument loadDocument(URL url) throws IOException { return loadDocument(url, null); } // Methods that allow customization of the parser and the callback public synchronized HTMLEditorKit.Parser getParser() { if (parser == null) { try { Class c = Class .forName("javax.swing.text.html.parser.ParserDelegator"); parser = (HTMLEditorKit.Parser) c.newInstance(); } catch (Throwable e) { } } return parser; } public synchronized HTMLEditorKit.ParserCallback getParserCallback( HTMLDocument doc) { return doc.getReader(0); } protected String getNewCharSet(ChangedCharSetException e) { String spec = e.getCharSetSpec(); if (e.keyEqualsCharSet()) { // The event contains the new CharSet return spec; } // The event contains the content type // plus ";" plus qualifiers which may // contain a "charset" directive. First // remove the content type. int index = spec.indexOf(";"); if (index != -1) { spec = spec.substring(index + 1); } // Force the string to lower case spec = spec.toLowerCase(); StringTokenizer st = new StringTokenizer(spec, " /t=", true); boolean foundCharSet = false; boolean foundEquals = false; while (st.hasMoreTokens()) { String token = st.nextToken(); if (token.equals(" ") || token.equals("/t")) { continue; } if (foundCharSet == false && foundEquals == false && token.equals("charset")) { foundCharSet = true; continue; } else if (foundEquals == false && token.equals("=")) { foundEquals = true; continue; } else if (foundEquals == true && foundCharSet == true) { return token; } // Not recognized foundCharSet = false; foundEquals = false; } // No charset found - return a guess return "8859_1"; } protected static HTMLEditorKit kit; protected static HTMLEditorKit.Parser parser; static { kit = new HTMLEditorKit(); } } class MenuBuilder { public static JMenu buildMenu(String name, MenuSpec[] menuSpecs, Hashtable actions) { int count = menuSpecs.length; JMenu menu = new JMenu(name); for (int i = 0; i < count; i++) { MenuSpec spec = menuSpecs[i]; if (spec.isSubMenu()) { // Recurse to handle a sub menu JMenu subMenu = buildMenu(spec.getName(), spec.getSubMenus(), actions); if (subMenu != null) { menu.add(subMenu); } } else if (spec.isAction()) { // It's an Action - add it directly to the menu menu.add(spec.getAction()); } else { // It's an action name - add it if possible String actionName = spec.getActionName(); Action targetAction = (Action) actions.get(actionName); // Create the menu item JMenuItem menuItem = menu.add(spec.getName()); if (targetAction != null) { // The editor kit knows the action menuItem.addActionListener(targetAction); } else { // Action not known - disable the menu item menuItem.setEnabled(false); } } } // Return null if nothing was added to the menu. if (menu.getMenuComponentCount() == 0) { menu = null; } return menu; } }
