麻烦大家帮我看看这个程序为什么导入不了文件啊?在此先谢谢了!!
import java.awt.*;
import java.awt.event.*;
import java.io.*;
class lianxi extends Frame
{
        lianxi(String str)
        {
                    super(str);
        }
            public static void main(String[] args)
            {
                        final lianxi x=new lianxi("菜单窗口");
                        x.setSize(600,400);
                        x.setLocation(180,180);
                        MenuBar y=new MenuBar();
                        Menu z1=new Menu("File");
                        Menu z2=new Menu("Edit");
                        MenuItem v1=new MenuItem("New");
                        MenuItem v2=new MenuItem("Open");
                        final TextArea Te=new TextArea();
                        x.add(Te);
                        v2.addActionListener(new ActionListener()
                        {
                                    public void actionPerformed(ActionEvent e)
                                    {
                                                FileDialog F1=new FileDialog(x,"导入文件",FileDialog.LOAD);
                                                F1.setVisible(true);
                                                String str=F1.getFile();
                                                if(str!=null)
                                                { 
                                                          try
                                                          {
                                                                      FileInputStream F2=new FileInputStream(str);
                                                                      byte[] a=new byte[10*1024];
                                                                      int len=F2.read(a); 
                                                                      Te.append(new String(a,0,len));   
                                                          }
                                                          catch(Exception ex)
                                                          {
                                                                      ex.printStackTrace();
                                                          }
                                                }
                                    }
                        });
                        MenuItem v3=new MenuItem("Save");
                        MenuItem v4=new MenuItem("Exit");
                        v4.addActionListener(new ActionListener()
                        {
                                    public void actionPerformed(ActionEvent e)
                                    {
                                                System.exit(0);
                                    }
                        });
                        MenuItem v5=new MenuItem("Copy");
                        MenuItem v6=new MenuItem("remove");
                        z1.add(v1);
                        z1.add(v2);
                        z1.add(v3);
                        z1.add(v4);
                        z2.add(v5);
                        z2.add(v6);
                        y.add(z1);
                        y.add(z2);
                        x.setMenuBar(y);
                  x.addWindowListener(new WindowAdapter()
                  {
                              public void windowClosing(WindowEvent e)
                              {
                                          System.exit(0);
                              }
            });
            x.setVisible(true);
      }
}