how to File listFiles in alphabetical order

Question

I ve got code as below   class ListPageXMLFiles implements FileFilter             Override         public boolean accept File pathname                    DebugLog i  ListPageXMLFiles    pathname is     pathname                    String regex      page   d 2    xml                   if pathname getAbsolutePath   matches regex                             return true                                    return false               public void loadPageTrees String xml dir path            ListPageXMLFiles filter xml files   new ListPageXMLFiles            File XMLDirectory   new File xml dir path           for File  xml file   XMLDirectory listFiles filter xml files                     loadPageTree  xml file                 The FileFilter is working nicely  but listFiles   seems to be listing the files in reverse alphabetical order   Is there some quick way of telling listFile   to list the files in alphabetical order

User · Answer

In Java 8   Arrays sort files   a  b  - gt  a getName   compareTo b getName        Reverse order   Arrays sort files   a  b  - gt  -a getName   compareTo b getName

User · Answer

This is my code    x000D   x000D          try   x000D              String folderPath           filePath trim          x000D              logger info  Path      folderPath   x000D              File folder   new File folderPath   x000D              File   listOfFiles   folder listFiles    x000D              int length   listOfFiles length  x000D              logger info  So luong files      length   x000D              ArrayList lt CdrFileBO gt  lstFile   new ArrayList lt  CdrFileBO gt     x000D   x000D              if  listOfFiles    null  amp  amp  length  gt  0    x000D                  int count   0  x000D                  for  int i   0  i  lt  length  i      x000D                      if  listOfFiles i  isFile      x000D                          lstFile add new CdrFileBO listOfFiles i     x000D                        x000D                    x000D                  Collections sort lstFile   x000D                  for  CdrFileBO bo   lstFile    x000D                        String newName   START NAME         getSeq SEQ START          DateSTR     s   x000D                      String newName   START NAME   DateSTR   getSeq SEQ START      DAT   x000D                      SEQ START   SEQ START   1  x000D                      bo getFile   renameTo new File folderPath   newName    x000D                      logger info  newName      newName   x000D                      logger info  Next file      getSeq SEQ START    x000D                    x000D   x000D                x000D            catch  Exception ex    x000D              logger error ex   x000D              ex printStackTrace    x000D            x000D   x000D   x000D

User · Answer

The listFiles method  with or without a filter does not guarantee any order   It does  however  return an array  which you can sort with Arrays sort     File   files   XMLDirectory listFiles filter xml files   Arrays sort files   for File  xml file   files                This works because File is a comparable class  which by default sorts pathnames lexicographically   If you want to sort them differently  you can define your own comparator   If you prefer using Streams   A more modern approach is the following  To print the names of all files in a given directory  in alphabetical order  do   Files list Paths get dirName   sorted   forEach System out  println    Replace the System out  println with whatever you want to do with the file names  If you want only filenames that end with  xml  just do   Files list Paths get dirName        filter s - gt  s toString   endsWith   xml         sorted        forEach System out  println    Again  replace the printing with whichever processing operation you would like

User · Answer

I think the previous answer is the best way to do it here is another simple way  just to print the sorted results    String path   tmp    String   dirListing   null   File dir   new File path    dirListing   dir list     Arrays sort dirListing    System out println Arrays deepToString dirListing

[java] how to File.listFiles in alphabetical order?

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