/**
 * データサイズを人間が読める形で取得.
 *
 * @param length
 * @return
 */
public static String getPrettyLength(long length) {
    long kilobyte = 1024;
    long megabyte = kilobyte * 1024;
    long gigabyte = megabyte * 1024;
    long terabyte = gigabyte * 1024;
    if ((length >= 0) && (length < kilobyte)) {
        return length + "B";
    } else if ((length >= kilobyte) && (length < megabyte)) {
        return (length / kilobyte) + "KB";
    } else if ((length >= megabyte) && (length < gigabyte)) {
        return (length / megabyte) + "MB";
    } else if ((length >= gigabyte) && (length < terabyte)) {
        return (length / gigabyte) + "GB";
    } else if (length >= terabyte) {
        return (length / terabyte) + "TB";
    } else {
        return length + "Bytes";
    }
}

/**
 * データサイズを人間が読める形で取得.
 *
 * @param length
 * @return
 */
public static String getPrettyLength(long length) {
    if (length <= 0) {
        return "0B";
    }
    String[] suffixes = {"B", "KB", "MB", "GB", "TB", "PB", "EB", "ZB", "YB"};
    int i = (int) Math.floor(Math.log(length) / Math.log(1024));
    return String.format("%.0f%s", (length / Math.pow(1024, i)), suffixes[i]);
}