Swing HTMLDocument 不包含所有 HTML 元素? [英] Swing HTMLDocument doesn't contain all the HTML elements?

问题描述

我有一个 Swing 应用程序，其中包含一个显示 HTML 文件的对话框.我是这样做的:

URL url = getClass().getResource("/resources/EULA.html");JDialog eulaDialog = new JDialog();JEdi​​torPane eulaEP = new JEditorPane();尝试 {eulaEP.setPage(url);} catch (IOException e1) {//TODO 自动生成的 catch 块e1.printStackTrace();}JScrollPane scrollPane = new JScrollPane(eulaEP);eulaDialog.getContentPane().add(scrollPane);eulaDialog.setBounds(400, 200, 700, 600);eulaDialog.setVisible(true);

这符合我的预期.它正确显示 HTML 文件.

我现在尝试在文档中找到一个元素，所以我这样做:

HTMLDocument htm = (HTMLDocument) eulaEP.getDocument();元素 el = htm.getElement("unique_id");

但这会返回 null(即使该元素显示在对话框中).

我决定通过这样做来检查文档中保存了哪些元素:

for (ElementIterator iterator = new ElementIterator(htm); iterator.next() != null;)

然而这仅返回了 4 个元素；html、正文、p 和内容.我的 HTML 文件有很多(还有什么是内容?)我做错了什么?

澄清一下，HTML 包含一个按钮，我想向这个按钮添加一个 ActionListener，这样我就可以在我的 Java 代码中点击它.

解决方案

在下面的例子中，

控制台:

BranchElement(div) 1,6元素:'BranchElement(html) 0,6'，名称:'html'，孩子:2，属性:1，叶:假属性:'名称'，值:'html'元素:'BranchElement(head) 0,1'，名称:'head'，子元素:1，属性:1，叶子:false属性:'name'，值:'head'元素:'BranchElement(p-implied) 0,1'，名称:'p-implied'，孩子:1，属性:1，叶:假属性:'name'，值:'p-implied'元素:'LeafElement(content) 0,1'，名称:'内容'，孩子:0，属性:2，叶子:真属性:'CR'，值:'真'属性:'名称'，值:'内容'内容 (0-1): ''元素:'BranchElement(body) 1,6'，名称:'body'，子元素:1，属性:1，叶子:false属性:'name'，值:'body'元素:'BranchElement(div) 1,6'，名称:'div'，子元素:1，属性:3，叶子:false属性:'对齐'，值:'中心'属性:'id'，值:'unique_id'属性:'名称'，值:'div'元素:'BranchElement(p-implied) 1,6'，名称:'p-implied'，孩子:2，属性:1，叶:假属性:'name'，值:'p-implied'元素:'LeafElement(content) 1,5'，名称:'内容'，孩子:0，属性:1，叶子:真属性:'名称'，值:'内容'内容 (1-5):'测试'元素:'LeafElement(content) 5,6'，名称:'内容'，孩子:0，属性:2，叶子:真属性:'CR'，值:'真'属性:'名称'，值:'内容'内容 (5-6): ''

代码:

import java.awt.EventQueue;导入 java.util.Enumeration;导入 javax.swing.JEditorPane;导入 javax.swing.JFrame;导入 javax.swing.text.AttributeSet;导入 javax.swing.text.BadLocationException;导入 javax.swing.text.Element;导入 javax.swing.text.ElementIterator;导入 javax.swing.text.StyleConstants;导入 javax.swing.text.html.HTML;导入 javax.swing.text.html.HTMLDocument;/*** @see http://stackoverflow.com/a/5614370/230513*/公共类测试{私有静态最终字符串文本= ""+ "<头></头>"+ "<身体>"+ "<div align=center id=unique_id>测试</div>"+ "</body>"+ "</html>";public static void main(String[] args) 抛出异常 {EventQueue.invokeLater(new Test()::display);}私人无效显示(){JFrame f = new JFrame("Test");f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);JEdi​​torPane jep = new JEditorPane("text/html", TEXT);jep.setEditable(false);f.add(jep);f.pack();f.setLocationRelativeTo(null);f.setVisible(true);HTMLDocument htmlDoc = (HTMLDocument) jep.getDocument();System.out.println(htmlDoc.getElement("unique_id"));ElementIterator iterator = new ElementIterator(htmlDoc);元素元素；while ((element = iterator.next()) != null) {尝试 {打印元素(htmlDoc，元素)；} catch (BadLocationException e) {e.printStackTrace(System.err);}}}private void printElement(HTMLDocument htmlDoc, Element element) 抛出 BadLocationException {AttributeSet attrSet = element.getAttributes();System.out.println(""+ "元素:'" + element.toString().trim()+ "', 名称:'" + element.getName()+ "', children: " + element.getElementCount()+ ", 属性:" + attrSet.getAttributeCount()+ ", 叶子: " + element.isLeaf());枚举 attrNames = attrSet.getAttributeNames();而 (attrNames.hasMoreElements()) {对象属性 = attrNames.nextElement();System.out.println(" 属性:'" + attr + "'，值:'"+ attrSet.getAttribute(attr) + "'");对象标签 = attrSet.getAttribute(StyleConstants.NameAttribute);if (attr == StyleConstants.NameAttribute&&标签 == HTML.Tag.CONTENT) {int startOffset = element.getStartOffset();int endOffset = element.getEndOffset();int length = endOffset - startOffset;System.out.printf(" 内容 (%d-%d): '%s'\n", startOffset,endOffset, htmlDoc.getText(startOffset, length).trim());}}}}

I have a swing application that contains a dialog displaying a HTML file. I do this like so:

URL url = getClass().getResource("/resources/EULA.html");

JDialog eulaDialog = new JDialog();
JEditorPane eulaEP = new JEditorPane();
try {
  eulaEP.setPage(url);
} catch (IOException e1) {
  // TODO Auto-generated catch block
  e1.printStackTrace();
}

JScrollPane scrollPane = new JScrollPane(eulaEP);
eulaDialog.getContentPane().add(scrollPane);
eulaDialog.setBounds(400, 200, 700, 600);
eulaDialog.setVisible(true);

This works as I expected. It displays the HTML file correctly.

I now try to find an element in the document so I do this:

HTMLDocument htm = (HTMLDocument) eulaEP.getDocument();
Element el = htm.getElement("unique_id");

But this returns null (even though the element is shown in the dialog).

I decided to check which elements were held in the document by doing this:

for (ElementIterator iterator = new ElementIterator(htm); iterator.next() != null;)

This however only returned 4 elements; html, body, p and content. My HTML file has a lot more (and what is content anyway?) What am I doing wrong?

Just to clarify, the HTML contains a button, I want to add an ActionListener to this button so I can catch a click on it in my java code.

解决方案

In the example below, HTMLDocument::getElement(String id) finds the Element whose HTML.Attribute.id attribute has the value "unique_id". The Element is BranchElement(div) 1,6

I'm not sure where your Element iteration goes awry, but you can see the unique_id value in the BranchElement(div) in the console output below. Because an HTMLDocument models HTML, the enclosed HTMLReader may synthesize HTML.Tag CONTENT, such as the content in the implied paragraphs seen below.

Console:

BranchElement(div) 1,6

Element: 'BranchElement(html) 0,6', name: 'html', children: 2, attributes: 1, leaf: false
  Attribute: 'name', Value: 'html'
Element: 'BranchElement(head) 0,1', name: 'head', children: 1, attributes: 1, leaf: false
  Attribute: 'name', Value: 'head'
Element: 'BranchElement(p-implied) 0,1', name: 'p-implied', children: 1, attributes: 1, leaf: false
  Attribute: 'name', Value: 'p-implied'
Element: 'LeafElement(content) 0,1', name: 'content', children: 0, attributes: 2, leaf: true
  Attribute: 'CR', Value: 'true'
  Attribute: 'name', Value: 'content'
    Content (0-1): ''
Element: 'BranchElement(body) 1,6', name: 'body', children: 1, attributes: 1, leaf: false
  Attribute: 'name', Value: 'body'
Element: 'BranchElement(div) 1,6', name: 'div', children: 1, attributes: 3, leaf: false
  Attribute: 'align', Value: 'center'
  Attribute: 'id', Value: 'unique_id'
  Attribute: 'name', Value: 'div'
Element: 'BranchElement(p-implied) 1,6', name: 'p-implied', children: 2, attributes: 1, leaf: false
  Attribute: 'name', Value: 'p-implied'
Element: 'LeafElement(content) 1,5', name: 'content', children: 0, attributes: 1, leaf: true
  Attribute: 'name', Value: 'content'
    Content (1-5): 'Test'
Element: 'LeafElement(content) 5,6', name: 'content', children: 0, attributes: 2, leaf: true
  Attribute: 'CR', Value: 'true'
  Attribute: 'name', Value: 'content'
    Content (5-6): ''

Code:

import java.awt.EventQueue;
import java.util.Enumeration;
import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.text.AttributeSet;
import javax.swing.text.BadLocationException;
import javax.swing.text.Element;
import javax.swing.text.ElementIterator;
import javax.swing.text.StyleConstants;
import javax.swing.text.html.HTML;
import javax.swing.text.html.HTMLDocument;

/**
 * @see http://stackoverflow.com/a/5614370/230513
 */
public class Test {

    private static final String TEXT
        = "<html>"
        + "<head></head>"
        + "<body>"
        + "<div align=center id=unique_id>Test</div>"
        + "</body>"
        + "</html>";

    public static void main(String[] args) throws Exception {
        EventQueue.invokeLater(new Test()::display);
    }

    private void display() {
        JFrame f = new JFrame("Test");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        JEditorPane jep = new JEditorPane("text/html", TEXT);
        jep.setEditable(false);
        f.add(jep);
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);

        HTMLDocument htmlDoc = (HTMLDocument) jep.getDocument();
        System.out.println(htmlDoc.getElement("unique_id"));
        ElementIterator iterator = new ElementIterator(htmlDoc);
        Element element;
        while ((element = iterator.next()) != null) {
            try {
                printElement(htmlDoc, element);
            } catch (BadLocationException e) {
                e.printStackTrace(System.err);
            }
        }
    }

    private void printElement(HTMLDocument htmlDoc, Element element) throws BadLocationException {
        AttributeSet attrSet = element.getAttributes();
        System.out.println(""
            + "Element: '" + element.toString().trim()
            + "', name: '" + element.getName()
            + "', children: " + element.getElementCount()
            + ", attributes: " + attrSet.getAttributeCount()
            + ", leaf: " + element.isLeaf());
        Enumeration attrNames = attrSet.getAttributeNames();
        while (attrNames.hasMoreElements()) {
            Object attr = attrNames.nextElement();
            System.out.println("  Attribute: '" + attr + "', Value: '"
                + attrSet.getAttribute(attr) + "'");
            Object tag = attrSet.getAttribute(StyleConstants.NameAttribute);
            if (attr == StyleConstants.NameAttribute
                && tag == HTML.Tag.CONTENT) {
                int startOffset = element.getStartOffset();
                int endOffset = element.getEndOffset();
                int length = endOffset - startOffset;
                System.out.printf("    Content (%d-%d): '%s'\n", startOffset,
                    endOffset, htmlDoc.getText(startOffset, length).trim());
            }
        }
    }
}

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