java日期操作工具类（获取指定日期、日期转换、相隔天数）

 import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.ArrayList; import java.util.Calendar; import java.util.Date; import java.util.List; public class DateUtil { /** * 获得指定日期的前一天 * * @param specifiedDay * @param format * @return * @throws Exception */ public static Date getDayBefore(Date date, String format) { Calendar c = Calendar.getInstance(); c.setTime(date); int day = c.get(Calendar.DATE); c.set(Calendar.DATE, day - 1); String dayBeforeStr = new SimpleDateFormat(format).format(c.getTime()); Date dayBefore = null; try { dayBefore = new SimpleDateFormat(format).parse(dayBeforeStr); } catch (ParseException e) { e.printStackTrace(); } return dayBefore; } /** * 获得指定日期的后一天 * * @param specifiedDay * @return */ public static Date getDayAfter(Date date, String format) { Calendar c = Calendar.getInstance(); c.setTime(date); int day = c.get(Calendar.DATE); c.set(Calendar.DATE, day + 1); String dayAfterStr = new SimpleDateFormat(format).format(c.getTime()); Date dayAfter = null; try { dayAfter = new SimpleDateFormat(format).parse(dayAfterStr); } catch (ParseException e) { e.printStackTrace(); } return dayAfter; } /** * 获得指定日期的前一天 * * @param specifiedDay * @param format * @return * @throws Exception */ public static String getSpecifiedDayBefore(String specifiedDay, String format) { // SimpleDateFormat simpleDateFormat = new // SimpleDateFormat("yyyy-MM-dd"); 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; } /** * 获得指定日期的后一天 * * @param specifiedDay * @return */ public static String getSpecifiedDayAfter(String specifiedDay, String format) { Calendar c = Calendar.getInstance(); Date date = null; try { // date = new SimpleDateFormat("yy-MM-dd").parse(specifiedDay); date = new SimpleDateFormat(format).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()); String dayAfter = new SimpleDateFormat(format).format(c.getTime()); return dayAfter; } /** * 将date类型准成指定format格式的字符串 * * @param day 日期 * @param format 指定格式 * @return */ public static String date2String(Date day, String format) { String dateStr = new SimpleDateFormat(format).format(day.getTime()); return dateStr; } /** * 将字符串转成指定格式的date类型 * * @param day 日期 * @param format 指定格式 * @return */ public static Date string2Date(String dateStr,String format) { Date strDate = null; try { strDate = new SimpleDateFormat(format).parse(dateStr); } catch (ParseException e) { e.printStackTrace(); } return strDate; } /** * * @Title: DateDate2CompareValue * @Description: 两个date类型比较大小 * @param dayAfter date类型 * @param date   date类型 * @param 格式化 * @return boolean * @throws */ public static boolean DateDate2CompareValue(Date dayAfter, Date date, String pattern) { SimpleDateFormat sdf = new SimpleDateFormat(pattern); try { Date d1 = sdf.parse(sdf.format(dayAfter)); Date d2 = sdf.parse(sdf.format(date)); if(d1.getTime()>=d2.getTime()){ return true; } } catch (ParseException e) { e.printStackTrace(); } return false; } /** * 比较两个日期年月日的大小 * @Title: DateCompareValue * @Description: 一个stirng一个date类型比较大小 * @param date1 String类型 * @param date2 date类型 * @param @return * @return boolean * @throws */ public static boolean DateStrDateCompareValue(String date1, Date date, String pattern) { SimpleDateFormat sdf = new SimpleDateFormat(pattern); try { Date d1 = sdf.parse(date1); Date d2 = sdf.parse(sdf.format(date)); if(d1.getTime()>=d2.getTime()){ return true; } } catch (ParseException e) { // TODO Auto-generated catch block e.printStackTrace(); } return false; } /** * 比较两个日期年月日的大小 * @Title: DateStr2CompareValue * @Description: 两个string类型比较时间大小 * @param date1 * @param date2 * @return boolean * @throws */ @SuppressWarnings("unused") public static boolean DateStr2CompareValue(String date1, String date2,String pattern) { SimpleDateFormat sdf = new SimpleDateFormat(pattern); try { Date d1 = sdf.parse(date1); Date d2 = sdf.parse(date2); if(d1.getTime()>=d2.getTime()){ return true; } } catch (ParseException e) { e.printStackTrace(); } return false; } /** * * @Title: get2DateListDate * @date 2016年5月17日 下午2:11:48 * @Description: 获取时间之内的 相隔天数的date集合 * @param @param preDate 开始时间 * @param @param nextDate 结束时间 * @param @param format  fomat格式 * @param @return * @return List 相隔天数集合 * @throws */ public static List get2DateListDate(String preDate, String nextDate, String format) { List list = new ArrayList<>(); if(nextDate.equals(preDate)){//开始时间 结束时间相等就直接返回 list.add(DateUtil.string2Date(preDate, format)); return list; } String nexDate = DateUtil.getSpecifiedDayAfter(preDate, format); list.add(DateUtil.string2Date(preDate, format)); list.add(DateUtil.string2Date(nexDate, format)); while (!nexDate.equals(nextDate)) { String nextnextDate = DateUtil.getSpecifiedDayAfter(nexDate, format); list.add(DateUtil.string2Date(nextnextDate, format)); nexDate = nextnextDate; } return list; } /** * * @Title: get2DateListDate * @date 2016年5月17日 下午2:11:48 * @Description: 获取时间之内的 相隔天数的string集合 * @param @param preDate 开始时间 * @param @param nextDate 结束时间 * @param @param format  fomat格式 * @param @return * @return List 相隔天数集合 * @throws */ public static List get2DateListDateStr(String preDate, String nextDate, String format) { List list = new ArrayList<>(); if(nextDate.equals(preDate)){//如果开始时间等于结束时间那么就是同一天 list.add(preDate); return list; } String nexDate = DateUtil.getSpecifiedDayAfter(preDate, format); list.add(preDate); list.add(nexDate); while (!nexDate.equals(nextDate)) { String nextnextDate = DateUtil.getSpecifiedDayAfter(nexDate, format); list.add(nextnextDate); nexDate = nextnextDate; } return list; } /** * * @Title: get2DateListWithDate * @date 2016年5月26日 上午9:20:29 * @Description: 获取两个日期之间日期的 * @param @param startDate 开始日期 date类型 * @param @param endDate  结束日期 date类型 * @param @return * @return List  datelist * @throws */ public static List get2DateListWithDate(Date startDate, Date endDate,String format) { List list = new ArrayList<>(); if(startDate.getTime() >endDate.getTime()){ return list; } String startDateStr = DateUtil.date2String(startDate, format); String endDateStr = DateUtil.date2String(endDate, format); if(startDateStr.equals(endDateStr)){//如果开始时间等于结束时间那么就是同一天 list.add(startDate); return list; } Date nextDate = DateUtil.getDayAfter(startDate, format); String nextDateStr = DateUtil.date2String(nextDate, format); //String endDateStr = DateUtil.date2String(endDate, format); list.add(startDate); list.add(nextDate); while (!nextDateStr.equals(endDateStr)) { String nextnextDate = DateUtil.getSpecifiedDayAfter(nextDateStr, format); list.add(DateUtil.string2Date(nextnextDate, format)); nextDateStr = nextnextDate; } return list; } public static void main(String[] args) throws Exception { /**/ String preDate = getSpecifiedDayBefore("2016-05-01", "yyyy-MM-dd"); String nextDate = getSpecifiedDayAfter("2016-05-03", "yyyy-MM-dd"); Date befroDay = getDayBefore(new Date(), "yyyy-MM-dd"); Date dateAfter = getDayAfter(new Date(), "yyyy-MM-dd"); // System.out.println("前一天：" + preDate + " 后一天:" + nextDate); // System.err.println("前一天：" +date2String( befroDay ,"yyyy-MM-dd")+ " // 后一天:" + dateAfter); String mat = "yyyy-MM-dd";// 这里最好从数据库中读取 SimpleDateFormat dateTimeFormat = new SimpleDateFormat(mat); Date dd = DateUtil.getDayBefore(new Date(), mat); // Date befroDay = getDayBefore(new Date(), "yyyy-MM-dd"); String sd = date2String(befroDay, "yyyy-MM-dd"); String dateStr = dateTimeFormat.format(befroDay); // System.out.println("dateStr="+dateStr+" sd "+sd); //List listDate = get2DateListDate("2016-05-01", "2016-05-03", "yyyy-MM-dd"); //List listDateStr = get2DateListDateStr("2016-05-01", "2016-05-03", "yyyy-MM-dd"); Date startDate = new Date(); Date endDate = dateTimeFormat.parse("2016-05-31"); List listDate = get2DateListWithDate(startDate,endDate,"yyyy-MM-dd"); for (int i = 0; i