Here you can find the source of getHumanSize(File dir)
public static String getHumanSize(File dir)
//package com.java2s; /*/* w ww .j a v a2 s. com*/ * Licensed to the Apache Software Foundation (ASF) under one * or more contributor license agreements. See the NOTICE file * distributed with this work for additional information * regarding copyright ownership. The ASF licenses this file * to you under the Apache License, Version 2.0 (the * "License") + you may not use this file except in compliance * with the License. You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, * software distributed under the License is distributed on an * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY * KIND, either express or implied. See the License for the * specific language governing permissions and limitations * under the License. */ import java.io.File; import java.text.DecimalFormat; public class Main { public static String getHumanSize(File dir) { return getHumanSize(getSize(dir)); } public static String getHumanSize(long size) { if (size <= 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]; } public static long getSize(File dir) { long size = 0; if (dir.isFile()) { size = dir.length(); } else { File[] subFiles = dir.listFiles(); for (File file : subFiles) { if (file.isFile()) { size += file.length(); } else { size += getSize(file); } } } return size; } }