Java获取当前时间或指定时间的上月当天及去年当月

/*** 获取当前时间的上月当天* @param formatPattern 指定日期格式* @return*/public static String getNowLastMonthThisDay(String formatPattern){LocalDateTime now1 = LocalDateTime.now();//获取上个月的当天（这一天）miuns()获取前面月份的方法,参数1为减去的数量，参数2为减去的对象（日，月）LocalDateTime minus = now1.minus(1, ChronoUnit.MONTHS);String lastMonthThisDay = minus.format(DateTimeFormatter.ofPattern(formatPattern));return lastMonthThisDay;}/*** 获取当前时间的去年当月* @param formatPattern* @return*/public static String getNowLastYearThisMonth(String formatPattern){LocalDateTime now1 = LocalDateTime.now();//获取上个月的当天（这一天）miuns()获取前面月份的方法,参数1为减去的数量，参数2为减去的对象（日，月）LocalDateTime minus = now1.minus(1, ChronoUnit.YEARS);String lastMonthThisDay = minus.format(DateTimeFormatter.ofPattern(formatPattern));return lastMonthThisDay;}/*** 获取指定日期的上月当天* @param assignTime 指定日期* @param formatPattern 指定日期格式* @return*/public static String getAssignLastMonthThisDay(String assignTime,String formatPattern){DateTimeFormatter format = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");LocalDateTime now1 = LocalDateTime.parse(assignTime,format);//获取上个月的当天（这一天）miuns()获取前面月份的方法,参数1为减去的数量，参数2为减去的对象（日，月）LocalDateTime minus = now1.minus(1, ChronoUnit.MONTHS);String lastMonthThisDay = minus.format(DateTimeFormatter.ofPattern(formatPattern));return lastMonthThisDay;}/*** 获取指定日期的去年当月* @param assignTime* @param formatPattern* @return*/public static String getAssignLastYearThisMonth(String assignTime,String formatPattern){DateTimeFormatter format = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");LocalDateTime now1 = LocalDateTime.parse(assignTime,format);//获取上个月的当天（这一天）miuns()获取前面月份的方法,参数1为减去的数量，参数2为减去的对象（日，月）LocalDateTime minus = now1.minus(1, ChronoUnit.YEARS);String lastMonthThisDay = minus.format(DateTimeFormatter.ofPattern(formatPattern));return lastMonthThisDay;}

//获取当前时间的上月当天String nowLastMonthThisTime = getNowLastMonthThisDay("yyyy-MM-dd");System.out.println("当前时间的上月当天" + nowLastMonthThisTime);//获取指定时间的上月当天String assign1 = getAssignLastMonthThisDay("2023-05-31 09:45:20", "yyyy-MM-dd HH:mm:ss");System.out.println("指定时间"+"2023-05-31 09:45:20"+"的上月当天" + assign1);String assign2 = getAssignLastMonthThisDay("2023-05-30 09:45:20", "yyyyMMdd");System.out.println("指定时间"+"2023-05-30 09:45:20"+"的上月当天" + assign2);String assign3 = getAssignLastMonthThisDay("2023-03-28 09:45:20", "yyyyMMdd");System.out.println("指定时间"+"2023-03-28 09:45:20"+"的上月当天" + assign3);String assign4 = getAssignLastMonthThisDay("2023-03-29 09:45:20", "yyyy-MM-dd HH:mm:ss");System.out.println("指定时间"+"2023-03-29 09:45:20"+"的上月当天" + assign4);String nowLastYearThisMonth = getNowLastYearThisMonth( "yyyyMMdd");System.out.println("当前时间的去年当月" + nowLastYearThisMonth);String assign5 = getAssignLastYearThisMonth("2023-02-29 09:45:20", "yyyyMM");System.out.println("指定时间"+"2023-02-29 09:45:20"+"的去年当月" + assign5);