如何在jtree中只列出非隐藏和非系统文件 [英] How to list only non hidden and non system file in jtree

问题描述

  File f = new File（C：/）; 
文件fList [] = f.listFiles（）; 
  

当我使用它时，会列出所有系统文件以及隐藏文件。
$ b

，导致空指针异常当我用它来显示在jTree中是这样的：

node.add（child）;
文件fList [] = f.listFiles（）;
for（int i = 0; i getList（child，fList [i]）;




$ b $ p
$ b $ p我该怎么做， strong> NullPointerException ，仅在jTree中显示非隐藏和非系统文件？

解决方案

对于隐藏文件执行此操作：

 文件root = new File（yourDirectory）; 
 File [] files = root.listFiles（new FileFilter（）{
 @Override 
 public boolean accept（File file）{
 return！file.isHidden（）; 
} 
}）; 
  

这不会返回隐藏文件。

至于系统文件，我相信这是一个Windows概念，因此可能不被 File 界面支持试图成为系统独立。尽管如此，你可以使用命令行命令。

或者使用@Reimeus在他的答案中。

可能类似于

  File root = new File（C：\\）; 
 
 File [] files = root.listFiles（new FileFilter（）{
 @Override 
 public boolean accept（File file）{
 Path path = Paths.get （file.getAbsolutePath（））; 
 DosFileAttributes dfa; 
 try {
 dfa = Files.readAttributes（path，DosFileAttributes.class）; 
} catch（IOException e）{
 // bad practice 
 return false; 
} 
 return（！dfa.isHidden（）&&！dfa.isSystem（））; 
} 
}）; 
  

DosFileAttributes是在Java 7中引入的。

File f=new File("C:/");
File fList[] = f.listFiles();

When i use this it list all system file as well as hidden files.

and this cause null pointer exception when i use it to show in jTree like this:

 public void getList(DefaultMutableTreeNode node, File f) {
 if(f.isDirectory()) {
     DefaultMutableTreeNode child = new DefaultMutableTreeNode(f);
     node.add(child);
     File fList[] = f.listFiles();
     for(int i = 0; i  < fList.length; i++)
         getList(child, fList[i]);
     }
}

What should i do so that it do not give NullPointerException and show only non hidden and non system files in jTree?

解决方案

Do this for hidden files:

File root = new File(yourDirectory);
File[] files = root.listFiles(new FileFilter() {
    @Override
    public boolean accept(File file) {
        return !file.isHidden();
    }
});

This will not return hidden files.

As for system files, I believe that is a Windows concept and therefore might not be supported by File interface that tries to be system independent. You can use Command line commands though, if those exist.

Or use what @Reimeus had in his answer.

Possibly like

    File root = new File("C:\\");

    File[] files = root.listFiles(new FileFilter() {
        @Override
        public boolean accept(File file) {
            Path path = Paths.get(file.getAbsolutePath());
            DosFileAttributes dfa;
            try {
                dfa = Files.readAttributes(path, DosFileAttributes.class);
            } catch (IOException e) {
                // bad practice
                return false;
            }
            return (!dfa.isHidden() && !dfa.isSystem());
        }
    });

DosFileAttributes was introduced in Java 7.

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