改写一个资源管理器实例的问题

Question

根据这个程序，我有以下几个问题1、我不需要从根目录展开Jtree，要从用户设定的路径（比如从“c:\windows”开始）展开，
我觉得这一句可能是有关路径的：
FileNode root=new FileNode(fileSystemView.getRoots()[0]);
但是，它的目录都不是字符串，我怎么自己设定啊？！
最大的问题就是这个例子里面，路径都不是字符串！！！2、它自定义了一个DetailTable，继承了JTable，我想实现双击表格的内容就可以打开文件（只打开txt文件），
 public void openSelect（）
是在这里写吗？有相关的代码例子吗？或者告诉我用什么函数实现。3、我想在表格里面添加一个排序的功能，按时间，按类型之类的，如何实现？4、如何刷新左面的JTree？用UpdateUI？还是？

Answer 1

源码
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public class WinExplorer extends JFrame implements TreeSelectionListener{
JPanel contentPane=(JPanel)getContentPane();;
JMenuBar menuBar = new JMenuBar();
JMenu menuFile = new JMenu("文件");
JMenuItem menuItemExit = new JMenuItem("退出");
JToolBar toolBar = new JToolBar();
JButton bttUp = new JButton();
Icon iconUp=UIManager.getIcon("FileChooser.upFolderIcon");
JLabel statusBar = new JLabel();//JTable的子类DetailTable，自己创建的=。=！
DetailTable detailTable = new DetailTable();
JScrollPane sp = new JScrollPane(detailTable);
JSplitPane split = new JSplitPane();//这是干什么用的？？？？
FileSystemView fileSystemView=FileSystemView.getFileSystemView();//返回此系统的所有根分区。
//例如，在 Windows 中，这将是“桌面”文件夹，而在 DOS 中将是从 A：到 Z：的驱动器。//这里是路径？？？！！！
FileNode root=new FileNode(fileSystemView.getRoots()[0]);DefaultTreeModel treeModel=new DefaultTreeModel(root);
JTree tree = new JTree(treeModel);public static void main(String argv[]){
    try {
      UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
      Font font=new Font("宋体",Font.PLAIN,12);
      String names[]={"Label","CheckBox","PopupMenu","TextPane",
                     "MenuItem","CheckBoxMenuItem","JRadioButtonMenuItem",
                     "ComboBox","Button","Tree","ScrollPane","TabbedPane",
                     "EditorPane","TitledBorder","Menu","TextArea","OptionPane",
                     "MenuBar","ToolBar","ToggleButton","ToolTip","ProgressBar",
                     "TableHeader","Panel","List","ColorChooser","PasswordField",
                     "TextField","Table","Label","Viewport","RadioButtonMenuItem",
                     "RadioButton"};
      for(int i=0;i<names.length;i++)UIManager.put(names[i]+".font",font);
      UIManager.put("Label.foreground",Color.black);
      UIManager.put("Border.foreground",Color.black);
      UIManager.put("TitledBorder.titleColor",Color.black);
      new WinExplorer().show();
   }catch(Exception e){
      e.printStackTrace();
   }
}//构造函数
public WinExplorer() {  //布局管理器  边界布局
  contentPane.setLayout(new BorderLayout());
  
  //窗口大小，居中
  Dimension dimension = getToolkit().getScreenSize();
  int i = (dimension.width - 640) / 2;
  int j = (dimension.height - 480) / 2;
  setBounds(i,j,640,480);
  setTitle("资源管理器");
  setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  setJMenuBar(menuBar);
  statusBar.setText(" ");  menuItemExit.addActionListener(new ActionListener()  {
    public void actionPerformed(ActionEvent e) {System.exit(0);}
  });  //设置“返回”按钮icon，以及动作
  bttUp.setIcon(iconUp);
  bttUp.addActionListener(new java.awt.event.ActionListener() {
      public void actionPerformed(ActionEvent e) {
      try{
          TreePath upPath=tree.getSelectionPath().getParentPath();
          if(upPath!=null){
                tree.setSelectionPath(upPath);
                tree.scrollPathToVisible(upPath);
          }
       }catch(Exception ex){}
    }
  });  //设置split窗口
  split.setDividerSize(6);
  split.setLeftComponent(new JScrollPane(tree));
  split.setRightComponent(sp);
  split.setDividerLocation(180);
  sp.getViewport().setBackground(Color.white);
 
  //设置并添加菜单栏、工具栏、状态栏等
  menuFile.add(menuItemExit);
  menuBar.add(menuFile);
  contentPane.add(toolBar, BorderLayout.NORTH);
  toolBar.add(bttUp, null);
  contentPane.add(statusBar, BorderLayout.SOUTH);
  contentPane.add(split, BorderLayout.CENTER);
  tree.addTreeExpansionListener(new MyExpandsionListener());
  //设置将用于绘制每个单元格的TreeCellRenderer
  tree.setCellRenderer(new MyTreeCellRenderer());  tree.addTreeSelectionListener(this);
  tree.setSelectionRow(0);  tree.setComponentOrientation(ComponentOrientation.UNKNOWN);
}//值变化
public void valueChanged(TreeSelectionEvent e){
   Object obj=tree.getLastSelectedPathComponent();
   if(obj==null)return;
   else detailTable.setParent(((FileNode)obj).getFile());
}// MyTreeCellRenderer类，继承DefaultTreeCellRenderer
class MyTreeCellRenderer extends DefaultTreeCellRenderer {
  public MyTreeCellRenderer() {}
  public Component getTreeCellRendererComponent(JTree tree,Object value,
            boolean sel,boolean expanded,boolean leaf,int row,boolean hasFocus) {
      super.getTreeCellRendererComponent(tree,value,sel,expanded,leaf,row,hasFocus);
      setIcon(fileSystemView.getSystemIcon(((FileNode)value).getFile()));
      return this;
  }
}//树展开、折叠
class MyExpandsionListener implements TreeExpansionListener {
  public MyExpandsionListener() {}
  public void treeExpanded(TreeExpansionEvent event) {
      if (tree.getLastSelectedPathComponent()==null){return;}
      tree.setCursor(new Cursor(Cursor.WAIT_CURSOR));
      TreePath path = event.getPath();
      FileNode node = (FileNode)path.getLastPathComponent();
      node.explore();
      treeModel.nodeStructureChanged(node);
      tree.setCursor(new Cursor(Cursor.DEFAULT_CURSOR));
  }
  public void treeCollapsed(TreeExpansionEvent event) {}
}

Answer 2

//结点
class FileNode extends DefaultMutableTreeNode {
    private boolean explored = false;
    public FileNode(File file)  { setUserObject(file); }
    public boolean getAllowsChildren() { return isDirectory(); }
    public boolean isLeaf()     { return !isDirectory();}
    public File getFile()        { return (File)getUserObject(); }
    public boolean isExplored() { return explored; }
    public void setExplored(boolean b){ explored=b;}
    public boolean isDirectory() { return getFile().isDirectory();}
    public String toString() {
        File file = (File)getUserObject();
        String filename = file.toString();
        int index = filename.lastIndexOf(File.separator);
        return (index != -1 && index != filename.length()-1)
                  ? filename.substring(index+1) : filename;
    }    //探索
    public void explore() {
        if(!isExplored()) {
            File file = getFile();
            File[] children = file.listFiles();
            if(children==null||children.length==0)return;
            for(int i=0; i < children.length; ++i)
            {
                 File f=children[i];
                 if(f.isDirectory())add(new FileNode(children[i]));
            }
            explored = true;
        }
   }
}//表？？？？？？
class DetailTable extends JTable{
      DetailTableModel model=new DetailTableModel();
      public DetailTable(){
          setModel(model);
          setShowGrid(false);
          TableColumnModel colModel = getColumnModel();
          for (int i=0;i<3;i++)
            colModel.getColumn(i).setCellRenderer(new DetailsTableCellRenderer());
          setRowHeight(18);
          this.addMouseListener(new MouseAdapter(){
              public void mouseClicked(MouseEvent e) {
                  if(e.getClickCount()==2){
                     for (int i = 0; i <getRowCount(); i++) {
                          if(getCellRect(i,0,true).contains(e.getPoint())){
                              openSelect();
                              break;
                          }
                      }
                  }
              }
          });
      }      public void openSelect(){
          Object obj=model.getValueAt(getSelectedRow(),0);
          if(obj==null)return;
          File f=(File)obj;
          if(f.isDirectory()){
              //expand tree
          }else{
              try{
          
                    }catch(Exception ee){}
              //open select file
          }
      }
      public void setParent(File parent){
          model.removeAllRows();
          File list[]=parent.listFiles();
          if(list==null)return;
          Vector vDir=new Vector(),vFile=new Vector();
          for (int i = 0; i < list.length; i++) {
              if(list[i].isDirectory())vDir.add(list[i]);
              else vFile.add(list[i]);
          }
          sortElements(vFile);
          sortElements(vDir);
          for (int i = 0; i < vDir.size(); i++)model.addFile((File)vDir.elementAt(i));
          for (int i = 0; i < vFile.size(); i++)model.addFile((File)vFile.elementAt(i));
      }
      public void sortElements(Vector v)
       {
          for(int i=0;i<v.size();i++)
          {
               int k=i;
               for(int j=i+1;j<v.size();j++){
                   File fa=(File)v.elementAt(j);
                   File fb=(File)v.elementAt(k);
                   if(fileSystemView.getSystemDisplayName(fa).toLowerCase().compareTo(
                        fileSystemView.getSystemDisplayName(fb).toLowerCase())<0)k=j;
               }
               if(k!=i)swap(k,i,v);
          }
       }
       private void swap(int loc1,int loc2,Vector v){
           Object tmp=v.elementAt(loc1);
           v.setElementAt(v.elementAt(loc2),loc1);
           v.setElementAt(tmp,loc2);
       }
       //表模型
      class DetailTableModel extends DefaultTableModel {
          public DetailTableModel() {
              addColumn("名称");
              addColumn("大小");
              addColumn("修改时间");
          }
          public void addFile(File f){
              addRow(new Object[]{f,new Double(f.length()/1024),
                   new java.sql.Date(f.lastModified())});
          }
          public void removeAllRows(){
              while(getRowCount()!=0) removeRow(0);
          }
          public boolean isCellEditable(int row, int column) {return false;}
      }      
      class DetailsTableCellRenderer extends DefaultTableCellRenderer {
        DetailsTableCellRenderer() {}
        public Component getTableCellRendererComponent(JTable table, Object value,
                              boolean isSelected, boolean hasFocus, int row, int column) {
            if (column == 1){
                setHorizontalAlignment(SwingConstants.TRAILING);
                isSelected=hasFocus=false;
            }else if(column==2){
                setHorizontalAlignment(SwingConstants.CENTER);
                isSelected=hasFocus=false;
            }else setHorizontalAlignment(SwingConstants.LEADING);
            return super.getTableCellRendererComponent(
                        table, value, isSelected, hasFocus, row, column);
        }
        public void setValue(Object value) {
            setIcon(null);
            if (value instanceof File) {
                File file = (File)value;
                setText(fileSystemView.getSystemDisplayName(file));
                setIcon(fileSystemView.getSystemIcon(file));
            }else{
                super.setValue(value);
            }
        }
    }
  }
}