Question

我在尝试获取文字（在他们的位置使用换行符）来自具有内容类型＆＃34; text / html＆＃34的JTextPane组件，我做错了什么？ ; ？

textPane.getText() 返回HTML但空白 head和body。 textPane.getDocument().getText() 返回空字符串。

P.S。：我在相同的代码中也没有换行和其他问题，我应该用相同的代码将它们作为独立问题提出来吗？

代码：

package test;

import java.io.IOException;
import java.io.StringReader;
import java.net.URL;
import java.util.logging.Level;
import java.util.logging.Logger;
import javax.swing.JScrollPane;
import javax.swing.text.BadLocationException;
//import javax.swing.text.StyledEditorKit;

public class TextPaneTester extends javax.swing.JFrame {

    public TextPaneTester() {
        initComponents();
        myInitComponents();
    }

    // <editor-fold defaultstate="collapsed" desc="Generated Code">                          
    private void initComponents() {
        contentScrollPane = new javax.swing.JScrollPane();
        content = new javax.swing.JTextPane();
        setDefaultCloseOperation(javax.swing.WindowConstants.EXIT_ON_CLOSE);
        contentScrollPane.setViewportView(content);

        // layout code by NetBeans
    }// </editor-fold>                        

    private void myInitComponents(){
        //content.setEditorKit(new StyledEditorKit());
        contentScrollPane.setVerticalScrollBarPolicy(JScrollPane.VERTICAL_SCROLLBAR_ALWAYS);
        contentScrollPane.setHorizontalScrollBarPolicy(JScrollPane.HORIZONTAL_SCROLLBAR_NEVER);
    }

    private void fetchURL(String url){
        try{
            // URL(URL baseURL[, String relativeURL])
            URL helpURL = new URL(url);
            System.out.println(helpURL);
            this.content.setPage(helpURL);

            try {
                System.out.println("This far!");
                //System.out.println(this.content.getDocument());
                System.out.println("getDocument() on JTextPane gives " + this.content.getDocument());
                System.out.println("getText() on JTextPane gives " + this.content.getText());

                // Why this line retuens an empty string?
                String text = this.content.getDocument().getText(0, this.content.getDocument().getLength());
                System.out.println("getDocument.getText() on JTextPane gives " + text);

                System.out.println("This far 2!");
                // this.translation.setPage(helpURL);
            } catch (BadLocationException ex) {
                System.out.println("Why this far!");
                Logger.getLogger(TextPaneTester.class.getName()).log(Level.SEVERE, null, ex);
            }

        }
        catch (IOException e) {
            System.err.println("Attempted to read a bad URL: " + url);
        }
        // return this.content;
    }

    /**
     * @param args the command line arguments
     */
    public static void main(String args[]) {
        /* Set the Nimbus look and feel */
        //<editor-fold defaultstate="collapsed" desc=" Look and feel setting code (optional) ">
        /* If Nimbus (introduced in Java SE 6) is not available, stay with the default look and feel.
         * For details see http://download.oracle.com/javase/tutorial/uiswing/lookandfeel/plaf.html 
         */
        try {
            for (javax.swing.UIManager.LookAndFeelInfo info : javax.swing.UIManager.getInstalledLookAndFeels()) {
                if ("Nimbus".equals(info.getName())) {
                    javax.swing.UIManager.setLookAndFeel(info.getClassName());
                    break;
                }
            }
        } catch (ClassNotFoundException ex) {
            java.util.logging.Logger.getLogger(TextPaneTester.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (InstantiationException ex) {
            java.util.logging.Logger.getLogger(TextPaneTester.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (IllegalAccessException ex) {
            java.util.logging.Logger.getLogger(TextPaneTester.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        } catch (javax.swing.UnsupportedLookAndFeelException ex) {
            java.util.logging.Logger.getLogger(TextPaneTester.class.getName()).log(java.util.logging.Level.SEVERE, null, ex);
        }
        //</editor-fold>

        /* Create and display the form */
        java.awt.EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                String url = "https://en.wikipedia.org/wiki/Virtaal";
                TextPaneTester reader = new TextPaneTester();
                reader.fetchURL(url);
                reader.setVisible(true);
            }
        });
    }

    private javax.swing.JTextPane content;
    private javax.swing.JScrollPane contentScrollPane;
    // End of variables declaration                   
}

输出：

run:
https://en.wikipedia.org/wiki/Virtaal
This far!
getDocument() on JTextPane gives javax.swing.text.html.HTMLDocument@1767743f
getText() on JTextPane gives <html>
  <head>

  </head>
  <body>
    <p style="margin-top: 0">

    </p>
  </body>
</html>

getDocument.getText() on JTextPane gives 
This far 2!
<html>
  <head>

  </head>
  <body>
    <p style="margin-top: 0">

    </p>
  </body>
</html>

Let's see what the parser gives: 
BUILD SUCCESSFUL (total time: 55 seconds)

Answer 1

像往常一样，documentation是你应该看的第一个地方：

如果文档是异步加载的，文档将立即通过调用setDocument安装到编辑器中，这将调用文档属性更改事件，然后将创建一个将开始执行实际加载的线程。在这种情况下，直接调用此方法不会触发页面属性更改事件，而是在执行加载的线程完成时触发。它也将在事件派发线程上触发。

您正在页面加载完成之前阅读文档。通过监视page属性等待加载：

this.content.addPropertyChangeListener("page",
    new PropertyChangeListener() {
        @Override
        public void propertyChange(PropertyChangeEvent event) {
            System.out.println("getText() on JTextPane gives "
                + content.getText());
        }
    });

this.content.setPage(helpURL);

为什么textPane.getDocument（）。getText（）返回空字符串？

1 个答案: