Get size of folder or file

Question

How can I retrieve size of folder or file in Java

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Using java-7 nio api  calculating the folder size can be done a lot quicker   Here is a ready to run example that is robust and won t throw an exception  It will log directories it can t enter or had trouble traversing  Symlinks are ignored  and concurrent modification of the directory won t cause more trouble than necessary          Attempts to calculate the size of a file or directory          lt p gt     Since the operation is non-atomic  the returned value may be inaccurate     However  this method is quick and does its best      public static long size Path path         final AtomicLong size   new AtomicLong 0        try           Files walkFileTree path  new SimpleFileVisitor lt Path gt                   Override             public FileVisitResult visitFile Path file  BasicFileAttributes attrs                     size addAndGet attrs size                     return FileVisitResult CONTINUE                              Override             public FileVisitResult visitFileFailed Path file  IOException exc                     System out println  skipped      file          exc                            Skip folders that can t be traversed                 return FileVisitResult CONTINUE                              Override             public FileVisitResult postVisitDirectory Path dir  IOException exc                     if  exc    null                      System out println  had trouble traversing      dir          exc                            Ignore errors traversing a folder                 return FileVisitResult CONTINUE                                  catch  IOException e            throw new AssertionError  walkFileTree will not throw IOException if the FileVisitor does not               return size get

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Here s the best way to get a general File s size  works for directory and non-directory    public static long getSize File file        long size      if  file isDirectory              size   0          for  File child   file listFiles                  size    getSize child                   else           size   file length              return size      Edit  Note that this is probably going to be a time-consuming operation   Don t run it on the UI thread   Also  here  taken from https   stackoverflow com a 5599842 1696171  is a nice way to get a user-readable String from the long returned   public static String getReadableSize long size        if size  lt   0  return  0       final String   units   new String      B    KB    MB    GB    TB         int digitGroups    int   Math log10 size  Math log10 1024        return new DecimalFormat      0     format size Math pow 1024  digitGroups                       units digitGroups

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Works for Android and Java Works for both folders and files Checks for null pointer everywhere where needed Ignores symbolic link aka shortcuts  Production ready    Source code      public long fileSize File root            if root    null               return 0                    if root isFile                 return root length                      try               if isSymlink root                    return 0                          catch  IOException e                e printStackTrace                return 0                     long length   0          File   files   root listFiles            if files    null               return 0                    for  File file   files                length    fileSize file                      return length             private static boolean isSymlink File file  throws IOException           File canon          if  file getParent      null                canon   file            else               File canonDir   file getParentFile   getCanonicalFile                canon   new File canonDir  file getName                       return  canon getCanonicalFile   equals canon getAbsoluteFile

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After lot of  researching and looking into different solutions proposed here at StackOverflow  I finally decided to write my own solution  My purpose is to have no-throw mechanism because I don t want to crash if the API is unable to fetch the folder size  This method is not suitable for mult-threaded scenario   First of all I want to check for valid directories while traversing down the file system tree   private static boolean isValidDir File dir       if  dir    null  amp  amp  dir exists    amp  amp  dir isDirectory             return true       else          return false            Second I do not want my recursive call to go into symlinks  softlinks  and include the size in total aggregate   public static boolean isSymlink File file  throws IOException       File canon      if  file getParent      null            canon   file        else           canon   new File file getParentFile   getCanonicalFile                    file getName               return  canon getCanonicalFile   equals canon getAbsoluteFile         Finally my recursion based implementation to fetch the size of the specified directory  Notice the null check for dir listFiles    According to javadoc there is a possibility that this method can return null   public static long getDirSize File dir       if   isValidDir dir           return 0L      File   files   dir listFiles          Guard for null pointer exception on files     if  files    null           return 0L       else          long size   0L          for File file   files               if  file isFile                     size    file length                 else                  try                      if   isSymlink file   size    getDirSize file                    catch  IOException ioe                         digest exception                                                   return size            Some cream on the cake  the API to get the size of the list Files  might be all of files and folder under root    public static long getDirSize List lt File gt  files       long size   0L      for File file   files           if  file isDirectory                 size    getDirSize file             else               size    file length                        return size

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For Java 8 this is one right way to do it   Files walk new File  D  temp   toPath                     map f - gt  f toFile                     filter f - gt  f isFile                     mapToLong f - gt  f length    sum     It is important to filter out all directories  because the length method isn t guaranteed to be 0 for directories   At least this code delivers the same size information like Windows Explorer itself does

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You can use Apache Commons IO to find the folder size easily    If you are on maven  please add the following dependency in your pom xml file    lt  -- https   mvnrepository com artifact commons-io commons-io -- gt   lt dependency gt       lt groupId gt commons-io lt  groupId gt       lt artifactId gt commons-io lt  artifactId gt       lt version gt 2 6 lt  version gt   lt  dependency gt    If not a fan of Maven  download the following jar and add it to the class path   https   repo1 maven org maven2 commons-io commons-io 2 6 commons-io-2 6 jar  public long getFolderSize          File folder   new File  src test resources        long size   FileUtils sizeOfDirectory folder        return size     in bytes     To get file size via Commons IO   File file   new File  ADD YOUR PATH TO FILE     long fileSize   FileUtils sizeOf file    System out println fileSize      bytes   It is also achievable via Google Guava   For Maven  add the following    lt  -- https   mvnrepository com artifact com google guava guava -- gt   lt dependency gt       lt groupId gt com google guava lt  groupId gt       lt artifactId gt guava lt  artifactId gt       lt version gt 28 1-jre lt  version gt   lt  dependency gt    If not using Maven  add the following to class path  https   repo1 maven org maven2 com google guava guava 28 1-jre guava-28 1-jre jar  public long getFolderSizeViaGuava             File folder   new File  src test resources            Iterable lt File gt  files   Files fileTreeTraverser                    breadthFirstTraversal folder           long size   StreamSupport stream files spliterator    false                   filter f - gt  f isFile                     mapToLong File  length  sum             return  size          To get file size    File file   new File  PATH TO YOUR FILE     long s    file length     System out println s

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for windows  using java io this reccursive function is useful       public static long folderSize File directory        long length   0       if  directory isFile             length    directory length        else          for  File file   directory listFiles                   if  file isFile                     length    file length                 else                  length    folderSize file                        return length      This is tested and working properly on my end

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in linux if you want to sort directories then  du -hs     sort -h

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java io File file   new java io File  myfile txt    file length      This returns the length of the file in bytes or 0 if the file does not exist  There is no built-in way to get the size of a folder  you are going to have to walk the directory tree recursively  using the listFiles   method of a file object that represents a directory  and accumulate the directory size for yourself   public static long folderSize File directory        long length   0      for  File file   directory listFiles              if  file isFile                length    file length            else             length    folderSize file             return length      WARNING  This method is not sufficiently robust for production use  directory listFiles   may return null and cause a NullPointerException  Also  it doesn t consider symlinks and possibly has other failure modes  Use this method

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In Java 8   long size   Files walk path  mapToLong  p - gt  p toFile   length     sum      It would be nicer to use Files  size in the map step but it throws a checked exception   UPDATE  You should also be aware that this can throw an exception if some of the files folders are not accessible  See this question and another solution using Guava

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public long folderSize  String directory                File curDir   new File directory           long length   0          for File f   curDir listFiles                          if f isDirectory                                                  for   File child   f listFiles                                             length   length   child length                                        System out println  Directory      f getName           length    kb                              else                               length   f length                    System out println  File      f getName           length    kb                              length   0                    return length

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I ve tested du -c  lt folderpath gt  and is 2x faster than nio Files or recursion  private static long getFolderSize File folder     if  folder    null  amp  amp  folder exists    amp  amp  folder canRead         try         Process p   new ProcessBuilder  du   -c  folder getAbsolutePath    start          BufferedReader r   new BufferedReader new InputStreamReader p getInputStream            String total             for  String line  null     line   r readLine              total   line        r close          p waitFor          if  total length    gt  0  amp  amp  total endsWith  total            return Long parseLong total split    s    0     1024        catch  Exception ex          ex printStackTrace                return -1

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You need FileUtils sizeOfDirectory File  from commons-io   Note that you will need to manually check whether the file is a directory as the method throws an exception if a non-directory is passed to it   WARNING  This method  as of commons-io 2 4  has a bug and may throw IllegalArgumentException if the directory is concurrently modified

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public static long getFolderSize File dir        long size   0      for  File file   dir listFiles              if  file isFile                  System out println file getName           file length                 size    file length                      else             size    getFolderSize file             return size

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private static long getFolderSize Path folder            try               return Files walk folder                         filter p - gt  p toFile   isFile                           mapToLong p - gt  p toFile   length                           sum              catch  IOException e                e printStackTrace                return 0L

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If you want to use Java 8 NIO API  the following program will print the size  in bytes  of the directory it is located in   import java io IOException  import java nio file Files  import java nio file Path  import java nio file Paths   public class PathSize        public static void main String   args            Path path   Paths get               long size   calculateSize path           System out println size                         Returns the size  in bytes  of the specified  lt tt gt path lt  tt gt   If the given        path is a regular file  trivially its size is returned  Else the path is        a directory and its contents are recursively explored  returning the        total sum of all files within the directory          lt p gt         If an I O exception occurs  it is suppressed within this method and         lt tt gt 0 lt  tt gt  is returned as the size of the specified  lt tt gt path lt  tt gt                   param path path whose size is to be returned         return size of the specified path             public static long calculateSize Path path            try               if  Files isRegularFile path                     return Files size path                              return Files list path  mapToLong PathSize  calculateSize  sum              catch  IOException e                return 0L                       The calculateSize method is universal for Path objects  so it also works for files  Note that if a file or directory is inaccessible  in this case the returned size of the path object will be 0

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The File object has a length method   f   new File  your file name    f length

User · Answer

File length    Javadoc    Note that this doesn t work for directories  or is not guaranteed to work   For a directory  what do you want   If it s the total size of all files underneath it  you can recursively walk children using File list   and File isDirectory   and sum their sizes

[java] Get size of folder or file

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