DELETE() method..need help!!

Question

private void deleteAll(){
File file;
String from = "C:/A/";
try {
file = new File(from);
} catch (Exception e) {
file = null;
e.printStackTrace();
if (file != null) {
String files[] = file.list();
for(int x = 0; x < files.length ; x ++){
File f = new File (files[x]);
if(f.isFile()){
f.delete();
}else{
System.out.print("WHAT PROBLEM?");
} else {
System.out.println("no such url");
} I wish to delete all files in C:/A/ when running this method..So anyone can find out what problems with my code..Thanks
Edited by: kahleong888 on Jun 14, 2008 9:06 PM

Answer 1

Kah,
To "prune" a whole directory and it's contents you need to depth-first-recurse the tree, (logically) pruning the branch you are standing on the way back up the tree... and if you (logically) recurse a "directory tree" from the "root" at the top... down to the "leaves" at the bottom, then shouldn't "trees" be called "roots" instead of "trees"... Hmmm... Just one of those things.
It goes something like this:
package forums;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
class Pruner
  public static void main(String[] args) {
    String top = args.length>0 ? args[0] : "C:/tmp/test/directoryToPrune";
    try {
      long start = System.currentTimeMillis();
      int n = prune(top);
      long took = System.currentTimeMillis()-start;
      System.out.println("Removed "+n+" objects from "+top+" in "+took+" milliseconds.");
    } catch (Exception e) {
      e.printStackTrace();
  private static int prune(String dirName)
    throws FileNotFoundException, IOException
    File dir = new File(dirName);
    if ( !dir.exists() ) {
      throw new FileNotFoundException("Not found: "+dir.getCanonicalPath());
    return recursivePrune(dir);
  private static int recursivePrune(File dir)
    throws FileNotFoundException, IOException
    String fullname = dir.getCanonicalPath();
    int count = 0;
    if ( dir.isDirectory() ) {
      for (File file : dir.listFiles()) {
        count += recursivePrune(file);
      // having removed dir's contents we continue and remove dir.
    // if dir isn't a dir then it must be a SINGLE file, soft-link, named-pipe...
    if (!dir.delete()) {
      throw new IOException("Failed to delete file: "+fullname);
    return count+1;
}I recommend you move the prune(String dirName) method (and it's recursivePrune(...) helper method) to an abstract utilz class (something like $yourInitials.utilz.io.Dirz), and make it public of course.
Cheers. Keith.