Java: get disk usage of a file or directory

• Option 1:

  import java.io.File;
  
  public class FileUtil {
  
   public static long getDiskUsage(File f) {
    if (f.isFile()) {
     return f.length();
    } else {
     int total = 0;
     File[] fs = f.listFiles();
     if (fs != null) {
      for (int i = 0; i < fs.length; i++) {
       total += getDiskUsage(fs[i]);
      }
     }
     return total;
    }
  
   }
  
   public static void main(String[] args) {
    System.out.println(getDiskUsage(new File("/tmp/1.png")));
   }
  }
  

• Option 2:

  import java.io.File;
  import java.io.FileFilter;
  
  public class DiskUsage implements FileFilter {
  
   private long _size = 0;
  
   public DiskUsage() {
  
   }
  
   @Override
   public boolean accept(File file) {
    if (file.isFile()) {
     _size += file.length();
    } else {
     file.listFiles(this);
    }
    return false;
   }
  
   public long getSize() {
    return _size;
   }
  
   public static void main(String[] args) {
    DiskUsage du = new DiskUsage();
    du.accept(new File("/tmp/1.png"));
    System.out.println(du.getSize());
   }
  }