日期计算——根据当前日期，得到前一天或后一天的日期

参考博客：(3条消息) java日期算前一天_java 根据系统日期获取前一天、后一天时间(根据初始日期推算出期望（向前/向后）日期)..._nbht的博客-CSDN博客

方法：

    @Testpublic void test2() {System.out.println(getCalculateDay(getDateTime(), 1));//2021-04-29System.out.println(getCalculateDay(getDateTime(), -1));//2021-04-27}public static String getCalculateDay(Object initTime, int n) {String calculateDay = "";try {Calendar calendar = Calendar.getInstance();SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");Date initDate = null;if (null == initTime) {initDate = new Date();} else if (initTime instanceof Date) {initDate = (Date) initTime;} else {initDate = sdf.parse((String) initTime);}calendar.setTime(initDate);calendar.add(Calendar.DATE, n);Date calculateDate = calendar.getTime();calculateDay = sdf.format(calculateDate);} catch (ParseException e) {e.printStackTrace();}return calculateDay;}public static String getDateTime() {return SHORT_DATE_FORMAT.format(new Date());}

日期计算——根据当前日期，得到前一天或后一天的日期

参考博客：(3条消息) java日期算前一天_java 根据系统日期获取前一天、后一天时间(根据初始日期推算出期望（向前/向后）日期)..._nbht的博客-CSDN博客

方法：

    @Testpublic void test2() {System.out.println(getCalculateDay(getDateTime(), 1));//2021-04-29System.out.println(getCalculateDay(getDateTime(), -1));//2021-04-27}public static String getCalculateDay(Object initTime, int n) {String calculateDay = "";try {Calendar calendar = Calendar.getInstance();SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");Date initDate = null;if (null == initTime) {initDate = new Date();} else if (initTime instanceof Date) {initDate = (Date) initTime;} else {initDate = sdf.parse((String) initTime);}calendar.setTime(initDate);calendar.add(Calendar.DATE, n);Date calculateDate = calendar.getTime();calculateDay = sdf.format(calculateDate);} catch (ParseException e) {e.printStackTrace();}return calculateDay;}public static String getDateTime() {return SHORT_DATE_FORMAT.format(new Date());}