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该File.listRoots()方法返回代表系统所有根文件夹的文件数组。我想创建一个逻辑文件并将所有这些根添加到它，所以我可以调用一个将File其作为参数的方法。

例如，给定这个伪方法：

void xyz(final File f) {
    // ....
} 

final File roots = somekindofwrapper(File.listRoots());
xyz(roots);

要求是roots在上面显示的伪代码中是一个包含系统上所有根的逻辑文件。这可能吗？

    import javax.swing.*;
    import java.io.File;
    public class FileTreeDemo {



    public static void main(String[] args) {

  try{  UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        }catch(Exception e){
            System.out.println("cant done"); 
        }
  // Create a JTree and tell it to display our model
  JTree tree = new JTree();

  // The JTree can get big, so allow it to scroll
  JScrollPane scrollpane = new JScrollPane(tree);
      // Figure out where in the filesystem to start displaying

  File[] roots = File.listRoots();  
  FileTreeModel model = new FileTreeModel(null);


     // for(File root: roots)
     // {
   model=new FileTreeModel(roots[0]);
       tree.setModel(model);
     // }




     JFrame frame = new JFrame("FileTreeDemo");
     frame.getContentPane().add(scrollpane, "Center");
     frame.setSize(400,600);
     frame.setVisible(true);

    }

    }


    import java.io.File;

    import javax.swing.event.TreeModelListener;
    import javax.swing.tree.DefaultTreeSelectionModel;
    import javax.swing.tree.TreeModel;
    import javax.swing.tree.TreePath;
    import javax.swing.tree.TreeSelectionModel;

    public class FileTreeModel  extends DefaultTreeSelectionModel implements TreeModel{
    // We specify the root directory when we create the model.

    protected File root;
    public FileTreeModel(File root) { this.root = root; 
    //setSelectionMode(TreeSelectionModel.DISCONTIGUOUS_TREE_SELECTION); 
    }

    // The model knows how to return the root object of the tree
    public Object getRoot() { return root; }

    // Tell JTree whether an object in the tree is a leaf
    public boolean isLeaf(Object node) {  return ((File)node).isFile(); }

    // Tell JTree how many children a node has
    public int getChildCount(Object parent) {
    String[] children = ((File)parent).list();
    if (children == null) return 0;
    return children.length;
    }

   // Fetch any numbered child of a node for the JTree.
   // Our model returns File objects for all nodes in the tree.  The
   // JTree displays these by calling the File.toString() method.
   public Object getChild(Object parent, int index) {
   String[] children = ((File)parent).list();
   if ((children == null) || (index >= children.length)) return null;
   return new File((File) parent, children[index]);
   }

   // Figure out a child's position in its parent node.
   public int getIndexOfChild(Object parent, Object child) {
   String[] children = ((File)parent).list();
   if (children == null) return -1;
   String childname = ((File)child).getName();
   for(int i = 0; i < children.length; i++) {
   if (childname.equals(children[i])) return i;
   }
   return -1;
   }

   // This method is invoked by the JTree only for editable trees.  
   // This TreeModel does not allow editing, so we do not implement 
   // this method.  The JTree editable property is false by default.
   public void valueForPathChanged(TreePath path, Object newvalue) {}

   // Since this is not an editable tree model, we never fire any events,
   // so we don't actually have to keep track of interested listeners*/
   public void addTreeModelListener(TreeModelListener l) {}
   public void removeTreeModelListener(TreeModelListener l) {}

   }
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1 回答 1

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File 对象是系统上物理文件的表示，您不能随意创建“虚拟文件”，其中包含其他文件的分组，与底层操作系统的现实脱节。您可能最接近您想要做的事情可能需要在系统上创建一个带有指向所有根的符号链接的文件夹 - 您可以在 Java 7 中执行此操作。我的直觉告诉我您正在尝试与现有代码集成，在我会问哪一点 - 一个接一个地用每个根文件调用你的函数有什么负面影响？

于 2012-04-14T06:10:03.587 回答