Java Day Add addDays(String dateStr, int nDays, String inputDateFormat, String outputDateFormat)

Description

add days to a given date

License

Open Source License

Parameter

Parameter	Description
dateStr	(in inputDateFormt)
nDays	a parameter

Return

modified date (in outputDatFormat) e.g., addDays("2008-02-28", 1, "yyyy-MM-dd", "MM/yy/dd") returns "02/08/29" addDays("2008-02-28", -29, "yyyy-MM-dd", "MM/yy/dd") returns "01/08/31" addDays("2008-02-28", 0, "yyyy-MM-dd", "MM/yy/dd") returns "02/08/28" (simply converts the date format)

Declaration

public static String addDays(String dateStr, int nDays, String inputDateFormat, String outputDateFormat)

Method Source Code

//package com.java2s;
/**/* w w w .ja  v  a  2 s .c om*/
 * Copyright (C) 2010-2014 Think Big Analytics, Inc. All Rights Reserved.
 *
 * Licensed 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. See accompanying LICENSE file.
 */

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.*;

public class Main {
    /**
      * add days to a given date
      * @param dateStr (in inputDateFormt)
      * @param nDays
      * @return modified date (in outputDatFormat)
      * e.g., addDays("2008-02-28", 1, "yyyy-MM-dd", "MM/yy/dd") returns "02/08/29"
      *        addDays("2008-02-28", -29, "yyyy-MM-dd", "MM/yy/dd") returns "01/08/31"
      *        addDays("2008-02-28", 0, "yyyy-MM-dd", "MM/yy/dd") returns "02/08/28" (simply converts the date format)
      */
    public static String addDays(String dateStr, int nDays, String inputDateFormat, String outputDateFormat) {

        try {

            DateFormat inputFormatter = new SimpleDateFormat(inputDateFormat);
            DateFormat outputFormatter = inputDateFormat.equals(outputDateFormat) ? inputFormatter
                    : new SimpleDateFormat(outputDateFormat);

            Date date = (Date) inputFormatter.parse(dateStr);

            Calendar calendar = Calendar.getInstance();
            calendar.setTime(date);
            calendar.add(Calendar.DATE, nDays);

            return outputFormatter.format(calendar.getTime());

        } catch (ParseException e) {

            return null;
        }
    }

    /**
     * add days to a given date
     * InputDateFormat = OutputDateFormat
     * @param dateStr
     * @param nDays
     * @param dateFormat
     * @return modifed date
     * e.g., addDays("2008-02-28", 1, "yyyy-MM-dd") returns 2008-02-29
     */
    public static String addDays(String dateStr, int nDays, String dateFormat) {
        return addDays(dateStr, nDays, dateFormat, dateFormat);
    }

    /**
     * add days to a given date
     * InputDateFormat = OutputDateFormat = yyyy-MM-dd
     * @param dateStr
     * @param nDays
     * @return modified date
     * e.g., addDays("2008-02-28", 1, "yyyy-MM-dd") returns 2008-02-29
     */
    public static String addDays(String dateStr, int nDays) {
        return addDays(dateStr, nDays, "yyyy-MM-dd");
    }
}