How can I retrieve size of folder or file in Java?
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Answer
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.