Group the files based on their extensions

Question

Hi,
I am traversing a dir and listing all the files under that directory. Now i want to group the files based on the extension and just print the number of files with each extension.
ex:
Extension No.of Files Size of the files
.java 10 23455 bytes
.html 2 1000 bytes
I am able to get the extension of the files. I would like to know how to proceed after that.
Any sample code will be helpful.
Regards
Kutty

Answer 1

I have used a method to list all the files in the directory. After adding files with same extension to the HashMap. i am printing files after reading file by file. I need to print the files once i complete reading all the files in the directory.
Any suggestions?
private void listingFiles(File f )
          Map extensionMap = null;
          File[] files = f.listFiles();
          for( int i = 0; i < files.length; i++ )
               File file1 = files;
               Dprop.size += files[i].length();
               if (file1.isFile())
                    fcount = fcount +1;     
                    if (extensionMap == null)
                         extensionMap = new HashMap();
                         // Group files by extension
                         for(int idx = 0; idx < files.length; idx++)
                              if (files[idx].isFile() && files[idx] != null)
                                   String ext = getExtension(files[idx]); // get the extension
                                   ext = ext.toLowerCase();
                                   List fileList = (List)extensionMap.get(ext);
                                   if(fileList == null)
                                   fileList = new ArrayList();
                                   extensionMap.put(ext, fileList);
                                   fileList.add(files[idx]);
                    // Access all the files by extension
                         for(Iterator extensionIterator = extensionMap.keySet().iterator(); extensionIterator.hasNext(); )
                              String ext = (String)extensionIterator.next();
                              List fileList = (List)extensionMap.get(ext);
                              System.out.println("\n\nNo of Files "+fileList.size()+" with extension '"+ext+"' in '"+f+ "' Directory");
                              for(Iterator fileIterator = fileList.iterator(); fileIterator.hasNext(); )
                                   File file = (File)fileIterator.next();
                              System.out.println("File Name "+file+" File Size "+file.length());
               else
                    dcount = dcount +1;
                    listingFiles( file1 );
Thanks in advance
Kutty