Get folder size

Question

Do you know how can I get the folder size in Java?

The length() method in the File class only works for files, using that method I always get a size of 0.

Answer 1

Folders generally have a very small "Size", you can think of them as an index.

All the programs that return a "Size" for a folder actually iterate and add up the size of the files.

Answer 2

Iterate over all subfolders in the folder and get the summary size of all files there.

Answer 3

import java.io.File;
import java.text.DecimalFormat;
import java.text.NumberFormat;

public class GetFolderSize {

  int totalFolder=0;
  int totalFile=0;

  public static void main(String args [])
  {  
    String folder = "C:/GetExamples";
        try{
    GetFolderSize size=new GetFolderSize();
    long fileSizeByte=size.getFileSize(new File(folder));
        System.out.println("Folder Size: "+fileSizeByte+" Bytes" );
    System.out.println("Total Number of Folders: "+size.getTotalFolder());
    System.out.println("Total Number of Files: "+size.getTotalFile());
    }catch (Exception e)
    {}
  }
  public long getFileSize(File folder) {
    totalFolder++; 
        System.out.println("Folder: " + folder.getName());
    long foldersize = 0;

    File[] filelist = folder.listFiles();
    for (int i = 0; i < filelist.length; i++) {
      if (filelist[i].isDirectory()) {
        foldersize += getFileSize(filelist[i]);
      } else {
        totalFile++;
        foldersize += filelist[i].length();
      }
    }
        return foldersize;
  }
  public int getTotalFolder() {
    return totalFolder;
  }
  public int getTotalFile() {
    return totalFile;
  }
}

Answer 4

Use apache-commons-io, there's a FileUtils class with a sizeOfDirectory methods

Answer 5

There is a slight error with simply recursively iterating over all subfolders. It is possible on some file systems to create circular directory structures using symbolic links as is demonstrated below:

mkdir -- parents father/son
ln -sf ${PWD}/father father/son
ls father/son/father/son/father/son/father/son/

To guard against this error, you can use the java.io.File#getCanonicalPath method. The code below is a slight modification of a previous answer.

      public static long getFileSize(File folder) throws IOException {
      return ( getFileSize ( folder , new HashSet < String > ( ) ) ) ;
  }
    public static long getFileSize(File folder , Set < String > history) throws IOException  {
    long foldersize = 0;

    File[] filelist = folder.listFiles();
    for (int i = 0; i < filelist.length; i++) {
    System . err . println ( "HISTORY" ) ;
    System . err . println ( history ) ;
    boolean inHistory = history . contains ( filelist[i].getCanonicalPath( )) ;
    history . add ( filelist[i].getCanonicalPath( ) ) ;
    if ( inHistory )
        {
        // skip it
        }
    else if (filelist[i].isDirectory()) {
      foldersize += getFileSize(filelist[i],history);
      } else {
        foldersize += filelist[i].length();
      }
    }
        return foldersize;
  }
}