22

I'm looking for a way to get all the names of directories in a given directory, but not files.

For example, let's say I have a folder called Parent, and inside that I have 3 folders: Child1 Child2 and Child3.

I want to get the names of the folders, but don't care about the contents, or the names of subfolders inside Child1, Child2, etc.

Is there a simple way to do this?

Aksel Willgert
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iaacp
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3 Answers3

24

If you are on java 7, you might wanna try using the support provided in 

package java.nio.file

If your directory has many entries, it will be able to start listing them without reading them all into memory first. read more in the javadoc: http://docs.oracle.com/javase/7/docs/api/java/nio/file/Files.html#newDirectoryStream(java.nio.file.Path,%20java.lang.String)

Here is also that example adapted to your needs:

public static void main(String[] args) {
    DirectoryStream.Filter<Path> filter = new DirectoryStream.Filter<Path>() {
        @Override
        public boolean accept(Path file) throws IOException {
            return (Files.isDirectory(file));
        }
    };

    Path dir = FileSystems.getDefault().getPath("c:/");
    try (DirectoryStream<Path> stream = Files.newDirectoryStream(dir, filter)) {
        for (Path path : stream) {
            // Iterate over the paths in the directory and print filenames
            System.out.println(path.getFileName());
        }
    } catch (IOException e) {
        e.printStackTrace();
    }
}
Aksel Willgert
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23

You can use String[] directories = file.list() to list all file names, then use loop to check each sub-files and use file.isDirectory() function to get subdirectories.

For example:

File file = new File("C:\\Windows");
String[] names = file.list();

for(String name : names)
{
    if (new File("C:\\Windows\\" + name).isDirectory())
    {
        System.out.println(name);
    }
}
bhuang3
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  • What's `"C\\Windows\\"` , `list()` returns the `absolutePath` – Mordechai Nov 23 '12 at 18:15
  • That sounds great! If I don't know exactly what the path will be up until a certain point, say "..\\Projects\\Tests\\Test1" being the only known part of the directory, will I still be able to do it this way? – iaacp Nov 23 '12 at 20:42
  • You mean the input will be a relative path? Because if we don't provide an absolute path, the program will treat it as a relative path to running program's current path. For example, if program's path is `C:\\Project\\Test`, and we input a pathname `abc`, then the program will treat it as `C:\\Project\\Test\\abc` – bhuang3 Nov 23 '12 at 21:55
  • @bhuang3 sorry but I'm not clear. What if I don't know the path before the Project directory? I'd like to run this on multiple computers, but each time from my Eclipse project. What would my File object look like when initialized? – iaacp Nov 24 '12 at 03:01
1
public static void displayDirectoryContents(File dir) {
    try {
        File[] files = dir.listFiles();
        for (File file : files) {
            if (file.isDirectory()) {
                System.out.println("Directory Name==>:" + file.getCanonicalPath());
                displayDirectoryContents(file);
            } else {
                System.out.println("file Not Acess===>" + file.getCanonicalPath());
            }
        }
    } catch (IOException e) {
        e.printStackTrace();
    }
}

}

====inside class/Method provide File=URL ======

    File currentDir = new File("/home/akshya/NetBeansProjects/");
    displayDirectoryContents(currentDir);
}