Java Time in GMT getGMTTimeStr(Date pageTime, int offset)

Description

get GMT Time string for given page date and offset, time would be formated to DEFAULT_DATE_FORMAT;

License

Apache License

Parameter

Parameter	Description
date	a parameter
offset	a parameter

Declaration

public static String getGMTTimeStr(Date pageTime, int offset) 

Method Source Code

//package com.java2s;
//License from project: Apache License 

import java.text.DateFormat;
import java.text.Format;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

import java.util.TimeZone;

public class Main {
    public final static String DEFAULT_DATE_FORMAT = "yyyy-MM-dd";

    /**/*from   www . j a va2  s  .com*/
     * get GMT Time string for given page date and offset, time would be
     * formated to DEFAULT_DATE_FORMAT;
     * 
     * @param date
     * @param offset
     * @return
     */
    public static String getGMTTimeStr(Date pageTime, int offset) {
        return formatDate(getGMTFromLocal(pageTime, offset), DEFAULT_DATE_FORMAT);
    }

    /**
     * Format date by the format
     * 
     * @param date
     *            - the source date
     * @param format
     *            - the date format
     * 
     * @return the result String
     */
    public static String formatDate(Date date, String format) {
        if (date == null)
            return null;

        Format formatter = new SimpleDateFormat(format);
        return formatter.format(date);
    }

    /**
     * Convert a local time to GMT time, the local time zone is specified by
     * offset
     * 
     * @param localTime
     * @param offset
     *            - offset to GMT time in term of hours, e.g. +1, +2, etc.
     * 
     * @return GMT time
     */
    public static Date getGMTFromLocal(Date localTime, int offset) {
        TimeZone tz1 = TimeZone.getTimeZone("GMT");
        if (offset > 0)
            tz1 = TimeZone.getTimeZone("GMT+" + String.valueOf(offset));
        else if (offset < 0)
            tz1 = TimeZone.getTimeZone("GMT" + String.valueOf(offset));

        return getTime(localTime, tz1, TimeZone.getTimeZone("GMT"));

    }

    public static Date getTime() {
        return Calendar.getInstance().getTime();
    }

    public static Date getTime(int field, int diff) {
        Calendar c = Calendar.getInstance();
        c.add(field, diff);
        return c.getTime();
    }

    /**
     * get time of dstTimeZone from time of srcTimeZone
     * 
     * @param time
     * @param srcTimeZone
     * @param dstTimeZone
     * @return Data
     */
    private static Date getTime(Date time, TimeZone srcTimeZone, TimeZone dstTimeZone) {
        if (time == null)
            return null;
        DateFormat df = new SimpleDateFormat(DEFAULT_DATE_FORMAT);
        df.setTimeZone(dstTimeZone);
        String gmtTime = df.format(time); // convert current time to gmt time.
        df.setTimeZone(srcTimeZone);
        try {
            return df.parse(gmtTime); // gmt time to date
        } catch (ParseException e) {
            return time;
        }

    }

    public static Date parse(String date, String format) throws ParseException {
        if (date == null)
            return null;

        SimpleDateFormat fmt = new SimpleDateFormat(format);

        return fmt.parse(date);
    }
}

Related

1. getGMTime()
2. getGMTString(Date d)
3. getGMTString(Date date, TimeZone tz)
4. getGMTTime(Date localTime)
5. getGMTTime(final Date date)
6. getGmtTimeString(double startTime)