Java File Size Get humanFileSize(Long longFileSize)

Description

Converts the size of a file to a human-readable string, e.g.

License

Open Source License

Parameter

Parameter	Description
longFileSize	The size to convert

Return

Human-readable string approximating that size.

Declaration

public static String humanFileSize(Long longFileSize) 

Method Source Code

//package com.java2s;

import java.text.DecimalFormat;
import java.text.FieldPosition;

public class Main {
    /**/*w  w  w  . jav a  2s . com*/
     * Converts the size of a file to a human-readable string, e.g.
     * "36 Kb", "1.2 Mb", etc. Contributor: Michael A. Russell
     * 
     * @param  longFileSize        The size to convert
     * @return                     Human-readable string approximating that size.
     */
    public static String humanFileSize(Long longFileSize) {
        /* If the input is negative, return a zero-length string.  */
        if (longFileSize < 0)
            return ("");

        /* If it's up to 512, use the number itself.  */
        if (longFileSize < 512)
            return (longFileSize.toString());

        /* Provide a place to put the result of the division.  */
        double doubleBytes;

        /* We want at most two digits to the right of the decimal point.  */
        DecimalFormat outputFormat = new DecimalFormat("0.00");

        /* Provide a place to put the converted value.  */
        StringBuffer outputStrBuf = new StringBuffer();

        /* Provide a "FieldPosition" object.  It looks like it's returned
         * by the "format( )" method, but I don't really care about it.
         * I haven't been able to find an example of how to use it, so
         * I'll just try using zero, and see what that does.
         */
        FieldPosition fieldPos = new FieldPosition(0);

        /* If it's up to 1024 * 512, express in terms of kilobytes.  */
        if (longFileSize < (1024L * 512L)) {
            doubleBytes = longFileSize.doubleValue() / 1024.0;
            outputFormat.format(doubleBytes, outputStrBuf, fieldPos);
            return (outputStrBuf.toString() + " Kb");
        }

        /* If it's up to 1024 * 1024 * 512, express in terms of megabytes.  */
        if (longFileSize < (1024L * 1024L * 512L)) {
            doubleBytes = longFileSize.doubleValue() / (1024.0 * 1024.0);
            outputFormat.format(doubleBytes, outputStrBuf, fieldPos);
            return (outputStrBuf.toString() + " Mb");
        }

        /* If it's up to 1024 * 1024 * 1024 * 512, express in terms of
         * gigabytes.
         */
        if (longFileSize < (1024L * 1024L * 1024L * 512L)) {
            doubleBytes = longFileSize.doubleValue() / (1024.0 * 1024.0 * 1024.0);
            outputFormat.format(doubleBytes, outputStrBuf, fieldPos);
            return (outputStrBuf.toString() + " Gb");
        }

        /* If it's up to 1024 * 1024 * 1024 * 1024 * 512, express in terms of
         * terabytes.
         */
        if (longFileSize < (1024L * 1024L * 1024L * 1024L * 512L)) {
            doubleBytes = longFileSize.doubleValue() / (1024.0 * 1024.0 * 1024.0 * 1024.0);
            outputFormat.format(doubleBytes, outputStrBuf, fieldPos);
            return (outputStrBuf.toString() + " Tb");
        }

        /* If it's up to 1024 * 1024 * 1024 * 1024 * 1024 * 512, express in
         * terms of petabytes.
         */
        if (longFileSize < (1024L * 1024L * 1024L * 1024L * 1024L * 512L)) {
            doubleBytes = longFileSize.doubleValue() / (1024.0 * 1024.0 * 1024.0 * 1024.0 * 1024.0);
            outputFormat.format(doubleBytes, outputStrBuf, fieldPos);
            return (outputStrBuf.toString() + " Pb");
        }

        /* Express in exabytes.  A long integer can be at most 2**63 - 1,
         * and that's about 9 exabytes, so we don't need to go higher.
         */
        doubleBytes = longFileSize.doubleValue() / (1024.0 * 1024.0 * 1024.0 * 1024.0 * 1024.0 * 1024.0);
        outputFormat.format(doubleBytes, outputStrBuf, fieldPos);
        return (outputStrBuf.toString() + " Eb");
    }
}

Related

1. getFileSizeStringFor(File file)
2. getFolderSize(File folder)
3. getSize(long fileSize)
4. getSizeErrorMessage(String pattern, Long maxFileSize, Long fileSize, String fileName)
5. getStringSizeLengthFile(long size)
6. humanReadableFileSize(long size)
7. prettyFileSize(long size)
8. readableFileSize(final long size)
9. readableFileSize(long size)