How to sort file names in ascending order?

Question

I have a set of files in a folder, and all of them starting with a similar name, except one. Here is an example:

Coordinate.txt
Spectrum_1.txt
Spectrum_2.txt         


        

Answer 1

You can find solution to your problem in comment above, but taking into consideration that only link had been published I'm giving code from that site. Worked great.

1. You need to create your own AlphanumericalComparator.

    import java.io.File;
    import java.util.Comparator;
   
   public class AlphanumFileComparator implements Comparator
   {
   
      private final boolean isDigit(char ch)
      {
       return ch >= 48 && ch <= 57;
      }
   
   
   private final String getChunk(String s, int slength, int marker)
   {
       StringBuilder chunk = new StringBuilder();
       char c = s.charAt(marker);
       chunk.append(c);
       marker++;
       if (isDigit(c))
       {
           while (marker < slength)
           {
               c = s.charAt(marker);
               if (!isDigit(c))
                   break;
               chunk.append(c);
               marker++;
           }
       } else
       {
           while (marker < slength)
           {
               c = s.charAt(marker);
               if (isDigit(c))
                   break;
               chunk.append(c);
               marker++;
           }
       }
       return chunk.toString();
   }
   
   public int compare(Object o1, Object o2)
   {
       if (!(o1 instanceof File) || !(o2 instanceof File))
       {
           return 0;
       }
       File f1 = (File)o1;
       File f2 = (File)o2;
       String s1 = f1.getName();
       String s2 = f2.getName();
   
       int thisMarker = 0;
       int thatMarker = 0;
       int s1Length = s1.length();
       int s2Length = s2.length();
   
       while (thisMarker < s1Length && thatMarker < s2Length)
       {
           String thisChunk = getChunk(s1, s1Length, thisMarker);
           thisMarker += thisChunk.length();
   
           String thatChunk = getChunk(s2, s2Length, thatMarker);
           thatMarker += thatChunk.length();
   
           /** If both chunks contain numeric characters, sort them numerically **/
   
           int result = 0;
           if (isDigit(thisChunk.charAt(0)) && isDigit(thatChunk.charAt(0)))
           {
               // Simple chunk comparison by length.
               int thisChunkLength = thisChunk.length();
               result = thisChunkLength - thatChunk.length();
               // If equal, the first different number counts
               if (result == 0)
               {
                   for (int i = 0; i < thisChunkLength; i++)
                   {
                       result = thisChunk.charAt(i) - thatChunk.charAt(i);
                       if (result != 0)
                       {
                           return result;
                       }
                   }
               }
           } else
           {
               result = thisChunk.compareTo(thatChunk);
           }
   
           if (result != 0)
               return result;
       }
   
       return s1Length - s2Length;
   }
   }
   

2. Sort your files, depending on this class.

     File[] listOfFiles = rootFolder.listFiles();
     Arrays.sort(listOfFiles, new AlphanumFileComparator() );
     ...to sth with your files.

Hope it helps. It worked for me, like a charm.

Solution from: http://www.davekoelle.com/files/AlphanumComparator.java here