小弟刚学swing ,在用JTextPane 时出现了问题
是把一个文件显示在JTextPane中，可是文件大了，就不能运行


具体代码如下:
package main;
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.text.*;
import java.io.*;

public class ReadDocContent implements Runnable 
{
    JFrame mainframe;
    JTextPane textpane=null;
    JInternalFrame internalframe=null;
    JFileChooser filechooser=null;
    Thread athread;
    SimpleAttributeSet attrset=new SimpleAttributeSet();
    
    public ReadDocContent(JTextPane pane,JFrame mf,JInternalFrame current)
    {
        this.mainframe=mf;
        this.textpane=pane;
        this.internalframe=current;
        
        filechooser=new JFileChooser();
        athread=new Thread(this);
        athread.start();
    }
    public void run()
    {
        File file=null;
        int result=filechooser.showOpenDialog(mainframe);
        textpane.setText("");
        
        if(result==JFileChooser.APPROVE_OPTION)
        {
            file=filechooser.getSelectedFile();
            internalframe.setTitle(file.getName());
        }
        else
        {
            internalframe.setTitle("you choose nothing");
        }
        
        BufferedReader in=null;
        
        if(file!=null)
        {
            try
            {
                in=new BufferedReader(new FileReader(file));
                
            }
            catch(FileNotFoundException e)
            {
                System.out.println("error");
                internalframe.setTitle("File Not Found");
                return;
            }
            
            Document doc=textpane.getDocument();
        
            String str;
            try
            {
                
                while((str=in.readLine())!=null)
                {
                    System.out.println(doc.getLength());
                    doc.insertString(doc.getLength(),str+"\n",attrset);
                    
                }
            }
            catch(IOException e)
            {
                System.out.println("error");
                internalframe.setTitle("io error");
                
            }
            catch(BadLocationException ble)
            {
                System.out.println("error");
                System.out.println(ble.getMessage());
            }
            finally
            {
                try
                {
                    in.close();
                }
                catch(IOException e)
                {
                    System.out.println("error");
                }
            
            }
        }
    }
}