java对日期时间的增减

import java.text.ParseException;import java.text.SimpleDateFormat;import java.util.Calendar;import java.util.Date;public class Util {static SimpleDateFormat sdf = new SimpleDateFormat("YYYY-mm-dd");/** * Java Calender类获得指定日期加几天 *  * @param specifiedDay * @param d  day * @return */public static String getSpecifiedDayAfter(String specified,int d) {Calendar c = Calendar.getInstance();Date date = null;try {date = new SimpleDateFormat("yy-MM-dd").parse(specified);} catch (ParseException e) {e.printStackTrace();}c.setTime(date);int day = c.get(Calendar.DATE);c.set(Calendar.DATE, day + d);String dayAfter = new SimpleDateFormat("yyyy-MM-dd").format(c.getTime());return dayAfter;}/** * Java Calender类获得指定日期加N月 *  * @param specifiedDay * @return */public static String getSpecifiedMonthAfter(String specified,int month) {Calendar c = Calendar.getInstance();Date date = null;try {date = new SimpleDateFormat("yy-MM-dd").parse(specified);} catch (ParseException e) {e.printStackTrace();}c.setTime(date);c.add(Calendar.MONTH,month); //int day = c.get(Calendar.DATE);//c.set(Calendar.DATE, day - 1);String dayAfter = new SimpleDateFormat("yyyy-MM-dd").format(c.getTime());return dayAfter;}/** * 比较两个时间的大小 * @param DATE1 * @param DATE2 * @return */ public static int compare_date(String DATE1, String DATE2) { int a = 0;        try {            Date dt1 = sdf.parse(DATE1);            Date dt2 = sdf.parse(DATE2);            if (dt1.getTime() > dt2.getTime()) {                //System.out.println("dt1 在dt2前");                a = 1;            } else if (dt1.getTime() < dt2.getTime()) {                //System.out.println("dt1在dt2后");                a = 2;            }else{            System.out.println("两个时间相等");            a = 0;            }        } catch (Exception exception) {            exception.printStackTrace();        }        return a;    }}