java 已知一個Date(),擷取前一天和後一天

import java.text.ParseException;import java.text.SimpleDateFormat;import java.util.Calendar;import java.util.Date;public class DateUtil {        public static void main(String[] args) {        Date date = new Date();        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");        String specifiedDay = sdf.format(date);        System.out.println(getSpecifiedDayBefore(specifiedDay));        System.out.println(getSpecifiedDayAfter(specifiedDay));    }        /**     * 獲得指定日期的前一天     *      * @param specifiedDay     * @return     * @throws Exception     */    public static String getSpecifiedDayBefore(String specifiedDay) {//可以用new Date().toLocalString()傳遞參數        Calendar c = Calendar.getInstance();        Date date = null;        try {            date = new SimpleDateFormat("yy-MM-dd").parse(specifiedDay);        } catch (ParseException e) {            e.printStackTrace();        }        c.setTime(date);        int day = c.get(Calendar.DATE);        c.set(Calendar.DATE, day - 1);        String dayBefore = new SimpleDateFormat("yyyy-MM-dd").format(c                .getTime());        return dayBefore;    }    /**     * 獲得指定日期的後一天     *      * @param specifiedDay     * @return     */    public static String getSpecifiedDayAfter(String specifiedDay) {        Calendar c = Calendar.getInstance();        Date date = null;        try {            date = new SimpleDateFormat("yy-MM-dd").parse(specifiedDay);        } catch (ParseException e) {            e.printStackTrace();        }        c.setTime(date);        int day = c.get(Calendar.DATE);        c.set(Calendar.DATE, day + 1);        String dayAfter = new SimpleDateFormat("yyyy-MM-dd")                .format(c.getTime());        return dayAfter;    }}