Java Date GMT Format toGMTString(Date dtIn)

Description

Convert a date into a format suitable for http headers etc "EEE, dd MMM yyyy HH:mm:ss z"

License

Open Source License

Parameter

Parameter	Description
dtIn	a parameter

Declaration

public static String toGMTString(Date dtIn) 

Method Source Code

//package com.java2s;
/** ***************************************************************
Util.java//from  ww  w. ja v  a 2  s.  c o  m
Copyright (C) 2001  Brendon Upson 
http://www.wnc.net.au info@wnc.net.au
    
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
    
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
    
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
    
 *************************************************************** */

import java.text.DateFormat;

import java.text.SimpleDateFormat;

import java.util.Date;

import java.util.Locale;
import java.util.TimeZone;

public class Main {
    public static final String SHORT_DATE = "shortdate";
    public static final String LONG_DATE = "longdate";
    public static final String SHORT_DATE_TIME = "shortdatetime";
    public static final String LONG_DATE_TIME = "longdatetime";

    /**
     * Convert a date into a format suitable for http headers etc "EEE, dd MMM yyyy HH:mm:ss z"
     * @param dtIn
     * @return
     */
    public static String toGMTString(Date dtIn) {
        if (dtIn == null)
            dtIn = new Date();
        String sGMTFormat = "EEE, dd MMM yyyy HH:mm:ss z";
        return formatDate(dtIn, sGMTFormat, Locale.UK, TimeZone.getTimeZone("GMT"));
    }

    /**
     * Format dates, convenience method
     * @param dtFormat
     * @param sFormatString
     * @return
     */
    public static String formatDate(java.util.Date dtFormat, String sFormatString) {
        return formatDate(dtFormat, sFormatString, Locale.getDefault(), TimeZone.getDefault());
    }

    /**
     * Convert a date into a formatted String. This will automatically do the timezone
     * conversion too.
     * To convert to a GMT string:
     * puakma.util.Util.formatDate(new java.util.Date(), "EEE, dd MMM yyyy HH:mm:ss z", Locale.UK, TimeZone.getTimeZone("GMT"));
     *
     * @param dtFormat Date to format; dtFormat; Locale (for languages); TimeZone
     * @param sFormatString
     * @param locale may be null
     * @param tz may be null
     * @return the string representation of the date of "" if the date could not be converted
     */
    public static String formatDate(Date dtFormat, String sFormatString, Locale locale, TimeZone tz) {
        if (sFormatString == null)
            sFormatString = "";

        if (dtFormat == null)
            return "";

        if (sFormatString.indexOf("date") >= 0) {
            // shortdate, longdate etc
            if (sFormatString.equalsIgnoreCase(SHORT_DATE)) {
                DateFormat df = null;
                if (locale != null)
                    df = DateFormat.getDateInstance(DateFormat.SHORT, locale);
                else
                    df = DateFormat.getDateInstance(DateFormat.SHORT);
                if (tz != null)
                    df.setTimeZone(tz);
                return df.format(dtFormat);
            }

            if (sFormatString.equalsIgnoreCase(SHORT_DATE_TIME)) {
                DateFormat df = null;
                if (locale != null)
                    df = DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.SHORT, locale);
                else
                    df = DateFormat.getDateTimeInstance(DateFormat.SHORT, DateFormat.SHORT);
                if (tz != null)
                    df.setTimeZone(tz);
                return df.format(dtFormat);
            }

            if (sFormatString.equalsIgnoreCase(LONG_DATE)) {
                DateFormat df = null;
                if (locale != null)
                    df = DateFormat.getDateInstance(DateFormat.LONG, locale);
                else
                    df = DateFormat.getDateInstance(DateFormat.LONG);
                if (tz != null)
                    df.setTimeZone(tz);
                return df.format(dtFormat);
            }

            if (sFormatString.equalsIgnoreCase(LONG_DATE_TIME)) {
                DateFormat df = null;
                if (locale != null)
                    df = DateFormat.getDateTimeInstance(DateFormat.LONG, DateFormat.SHORT, locale);
                else
                    df = DateFormat.getDateTimeInstance(DateFormat.LONG, DateFormat.SHORT);
                if (tz != null)
                    df.setTimeZone(tz);
                return df.format(dtFormat);
            }
            //we should never get here...
        }

        //regular formatting, eg "dd/MM/yy"
        SimpleDateFormat sdf;
        if (sFormatString.length() == 0)
            sdf = new SimpleDateFormat();
        else {
            if (locale == null)
                sdf = new SimpleDateFormat(sFormatString);
            else
                sdf = new SimpleDateFormat(sFormatString, locale);
        }
        if (tz != null)
            sdf.setTimeZone(tz);

        try {
            return sdf.format(dtFormat);
        } catch (Exception p) {
        }

        return "";
    }

    /**
     * Returns the position of one byte array within another.
     * @param src
     * @param find
     * @return -1 if not found
     */
    public static int indexOf(byte src[], byte find[]) {
        if (src == null || find == null || find.length == 0)
            return -1;
        int i = -1;
        for (i = 0; i < src.length; i++) {
            if (src[i] == find[0]) {
                boolean bOK = true;
                for (int k = 0; k < find.length; k++) {
                    int iSrcPos = i + k;
                    if (iSrcPos >= src.length)
                        return -1;
                    if (src[iSrcPos] != find[k])
                        bOK = false;
                } //for k
                if (bOK)
                    return i;
            }
        } //for i

        return -1;
    }

    /**
     * Returns the position of one byte array within another.
     * @param src
     * @param find
     * @return -1 if not found
     */
    public static int indexOf(char src[], char find[]) {
        if (src == null || find == null || find.length == 0)
            return -1;
        int i = -1;
        for (i = 0; i < src.length; i++) {
            if (src[i] == find[0]) {
                boolean bOK = true;
                for (int k = 0; k < find.length; k++) {
                    int iSrcPos = i + k;
                    if (iSrcPos >= src.length)
                        return -1;
                    if (src[iSrcPos] != find[k])
                        bOK = false;
                } //for k
                if (bOK)
                    return i;
            }
        } //for i

        return -1;
    }
}

Related

1. parseGMT(String gmtTime)
2. parseGMTDatetime(String str)
3. parseGMTTime(Long time, String format)
4. timeStampGMT(Date date)
5. toGMTString(Date d)
6. toStringWithoutGMT(Date date)