Question

我想用JTree创建一个非常简单的文件管理器，但我只看到一个非常难的代码，我想创建这个脚本非常干净和简单。

你能帮帮我吗？如何在JTree中列出计算机的目录？

Answer 1

我写了一个我能想到的最简单的文件浏览器示例。它列出了Windows计算机上C：驱动器上的所有目录和文件。

这是结果。

File Browser Swing JFrame

这是代码。我将所有内容放在一个类中，以便更容易粘贴到此处。你应该把课程分开。

package com.ggl.testing;

import java.io.File;

import javax.swing.JFrame;
import javax.swing.JScrollPane;
import javax.swing.JTree;
import javax.swing.SwingUtilities;
import javax.swing.tree.DefaultMutableTreeNode;
import javax.swing.tree.DefaultTreeModel;

public class FileBrowser implements Runnable {

    private DefaultMutableTreeNode root;

    private DefaultTreeModel treeModel;

    private JTree tree;

    @Override
    public void run() {
        JFrame frame = new JFrame("File Browser");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

        File fileRoot = new File("C:/");
        root = new DefaultMutableTreeNode(new FileNode(fileRoot));
        treeModel = new DefaultTreeModel(root);

        tree = new JTree(treeModel);
        tree.setShowsRootHandles(true);
        JScrollPane scrollPane = new JScrollPane(tree);

        frame.add(scrollPane);
        frame.setLocationByPlatform(true);
        frame.setSize(640, 480);
        frame.setVisible(true);

        CreateChildNodes ccn = 
                new CreateChildNodes(fileRoot, root);
        new Thread(ccn).start();
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new FileBrowser());
    }

    public class CreateChildNodes implements Runnable {

        private DefaultMutableTreeNode root;

        private File fileRoot;

        public CreateChildNodes(File fileRoot, 
                DefaultMutableTreeNode root) {
            this.fileRoot = fileRoot;
            this.root = root;
        }

        @Override
        public void run() {
            createChildren(fileRoot, root);
        }

        private void createChildren(File fileRoot, 
                DefaultMutableTreeNode node) {
            File[] files = fileRoot.listFiles();
            if (files == null) return;

            for (File file : files) {
                DefaultMutableTreeNode childNode = 
                        new DefaultMutableTreeNode(new FileNode(file));
                node.add(childNode);
                if (file.isDirectory()) {
                    createChildren(file, childNode);
                }
            }
        }

    }

    public class FileNode {

        private File file;

        public FileNode(File file) {
            this.file = file;
        }

        @Override
        public String toString() {
            String name = file.getName();
            if (name.equals("")) {
                return file.getAbsolutePath();
            } else {
                return name;
            }
        }
    }

}

Answer 2

这是我在为项目遇到问题时解决问题的方法，该项目涉及一个jtree来显示扫描结果。

scanner函数用于初始化参数并调用displayDirectoryContents函数

以下是我使用的方法的一些缺点

它将空文件夹显示为叶节点，而不是将它们显示为没有孩子的叶子

应通过右键单击属性并清除模型

手动清除模型

使用的功能

public void displayDirectoryContents(File dir,DefaultMutableTreeNode root2) throws InterruptedException 
{   
        DefaultMutableTreeNode newdir = new DefaultMutableTreeNode();    

        File[] files = dir.listFiles();  //creates array of file type for all the files found

        for (File file : files)
            {
                        if(file == null)
                        {
                            System.out.println("NUll directory found ");
                            continue;
                        }
                if (file.isDirectory())
                {
                    //file is a directory that is a folder has been dound 

                    if (file.listFiles()==null)
                    {
                        //skips null files
                        continue;
                    }

                    //gets the current model of the jtree
                    DefaultTreeModel model =(DefaultTreeModel) result.getModel();

                    //gets the root 
                    DefaultMutableTreeNode root=(DefaultMutableTreeNode) model.getRoot();

                    //generates a node newdir using filename  
                    newdir = new DefaultMutableTreeNode(file.getName());

                    //adds a node to the root of the jtree
                    root2.add(newdir);

                    //refresh the model to show the changes
                    model.reload();

                    //recursively calls the function again to explore the contents folder
                    displayDirectoryContents(file,newdir);
                }
                else
                {
                    // Else part File is not a directory



                    //gets the current model of the tree
                    DefaultTreeModel model =(DefaultTreeModel) result.getModel();

                    //selected node is the position where the new node will be inserted
                    DefaultMutableTreeNode selectednode = root2;

                    DefaultMutableTreeNode newfile =new DefaultMutableTreeNode(file.getName());


                    //inserts a node newfile under selected node which is the root
                    model.insertNodeInto(newfile, selectednode, selectednode.getChildCount());

                    //refresh the model to show the changes
                    model.reload();




                }

            }    
    }

扫描仪功能初始化上述功能

public void scanner() throws InterruptedException {    
// creates a file with the location filename
String location ="C:\\Users\\Ashish Padalkar\\Documents";
File currentDir = new File(location);

    //result is the variable name for jtree
    DefaultTreeModel model =(DefaultTreeModel) result.getModel();
    //gets the root of the current model used only once at the starting
    DefaultMutableTreeNode root=(DefaultMutableTreeNode) model.getRoot();
    //function caled
    displayDirectoryContents(currentDir,root);
}

这是我关于堆栈溢出的第一个答案：）

使用Jtree和Java中的文件列出文件和目录

2 个答案: