deleting folder from java

Question

hi, i want to delete all the contents that are present in a folder which includes files and folder too. I have written a java code to delete all the files but i am unable to delete the folders. below is the code i am using..

public void startDeleting(String path) {
        List<String> filesList = new ArrayList<String>();
        List<String> folderList = new ArrayList<String>();
        fetchCompleteList(filesList, folderList, path);
        for(String filePath : filesList) {
            File tempFile = new File(filePath);
            tempFile.delete();
        }
        for(String filePath : folderList) {
            File tempFile = new File(filePath);
            tempFile.delete();
        }
    }

private void fetchCompleteList(List<String> filesList, List<String> folderList, String path) {
    File file = new File(path);
    File[] listOfFile = file.listFiles();
    for(File tempFile : listOfFile) {
        if(tempFile.isDirectory()) {
            folderList.add(tempFile.getAbsolutePath());
            fetchCompleteList(filesList, folderList, tempFile.getAbsolutePath());
        } else {
            filesList.add(tempFile.getAbsolutePath());
        }

    }

}

Please help me if i am missing something in the code??..

Answer 1

I have something like this :

public static boolean deleteDirectory(File directory) {
    if(directory.exists()){
        File[] files = directory.listFiles();
        if(null!=files){
            for(int i=0; i<files.length; i++) {
                if(files[i].isDirectory()) {
                    deleteDirectory(files[i]);
                }
                else {
                    files[i].delete();
                }
            }
        }
    }
    return(directory.delete());
}

Answer 2

Try this:

public static boolean deleteDir(File dir) 
{ 
  if (dir.isDirectory()) 
{ 
  String[] children = dir.list(); 
  for (int i=0; i<children.length; i++)
  { 
    boolean success = deleteDir(new File(dir, children[i])); 
    if (!success) 
    {  
      return false; 
    } 
  } 
  // The directory is now empty so delete it 
  return dir.delete(); 
} 

Answer 3

It could be problem with nested folders. Your code deletes the folders in the order they were found, which is top-down, which does not work. It might work if you reverse the folder list first.

But I would recommend you just use a library like Commons IO for this.

Answer 4

You're storing all (sub-) files and folder recursively in a list, but with your current code you store the parent folder before you store the children. And so you try to delete the folder before it is empty. Try this code:

   if(tempFile.isDirectory()) {
        // children first
        fetchCompleteList(filesList, folderList, tempFile.getAbsolutePath());
        // parent folder last
        folderList.add(tempFile.getAbsolutePath());
   }

Answer 5

The javadoc for File.delete()

public boolean delete()

Deletes the file or directory denoted by this abstract pathname. If this pathname >denotes a directory, then the directory must be empty in order to be deleted.

So a folder has to be empty or deleting it will fail. Your code currently fills the folder list with the top most folder first, followed by its sub folders. Since you iterrate through the list in the same way it will try to delete the top most folder before deleting its subfolders, this will fail.

Changing these line

    for(String filePath : folderList) {
        File tempFile = new File(filePath);
        tempFile.delete();
    }

to this

    for(int i = folderList.size()-1;i>=0;i--) {
        File tempFile = new File(folderList.get(i));
        tempFile.delete();
    }

should cause your code to delete the sub folders first.

The delete operation also returns false when it fails, so you can check this value to do some error handling if necessary.

Answer 6

I wrote a method for this sometime back. It deletes the specified directory and returns true if the directory deletion was successful.

/**
 * Delets a dir recursively deleting anything inside it.
 * @param dir The dir to delete
 * @return true if the dir was successfully deleted
 */
public static boolean deleteDirectory(File dir) {
    if(! dir.exists() || !dir.isDirectory())    {
        return false;
    }

    String[] files = dir.list();
    for(int i = 0, len = files.length; i < len; i++)    {
        File f = new File(dir, files[i]);
        if(f.isDirectory()) {
            deleteDirectory(f);
        }else   {
            f.delete();
        }
    }
    return dir.delete();
}

Answer 7

If you use Apache Commons IO it's a one-liner:

FileUtils.deleteDirectory(dir);

See FileUtils.deleteDirectory()

---

Also with Guava:

Files.deleteRecursively(dir);

See Files.deleteRecursively()

Answer 8

Using the FileUtils.deleteDirectory() method can help to simplify the process of deleting directory and everything below it recursively.

Check this question

Answer 9

You should delete the file in the folder first , then the folder.This way you will recursively call the method.