Here you can find the source of getFileSize(File file)
public static long getFileSize(File file)
//package com.java2s; /*//from w w w . ja v a2 s . com * This file is part of UltimateCore, licensed under the MIT License (MIT). * * Copyright (c) Bammerbom * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN * THE SOFTWARE. */ import java.io.*; import java.util.*; public class Main { public static long getFileSize(File file) { if (!file.exists()) { return 0L; } if (file.isDirectory()) { long size = 0L; for (File subfile : listFiles(file)) { size += getFileSize(subfile); } return size; } return file.length(); } public static Iterable<File> listFiles(File directory) { return Arrays.asList(directory.listFiles()); } }