java根据当前月份获取上一个月 java 获取上个月

开始时间
public static String min = " 00:00:00";
结束时间
public static String max = " 23:59:59";

 public static void main(String[] args) throws Exception {
        //自定义时间
        System.out.println("当前天的开始"+getStartOrEndDayOfDay("2023-01-01",0,true));
        System.out.println("当前天的结束"+getStartOrEndDayOfDay("2023-01-01",0,false));
        System.out.println("当前天前一天的开始"+getStartOrEndDayOfDay("2023-01-01",-1,true));
        System.out.println("当前天前一天的结束"+getStartOrEndDayOfDay("2023-01-01",-1,false));
        System.out.println();
        System.out.println();
        System.out.println("当前周的开始"+getStartOrEndDayOfWeek("2023-01-01",0,true));
        System.out.println("当前周的结束"+getStartOrEndDayOfWeek("2023-01-01",0,false));
        System.out.println("当前周前一周的开始"+getStartOrEndDayOfWeek("2023-01-01",-1,true));
        System.out.println("当前周前一周的结束"+getStartOrEndDayOfWeek("2023-01-01",-1,false));
        System.out.println();
        System.out.println();
        System.out.println("当前月的开始"+getStartOrEndDayOfMonth("2023-01-01",0,true));
        System.out.println("当前月的结束"+getStartOrEndDayOfMonth("2023-01-01",0,false));
        System.out.println("当前月前一月的开始"+getStartOrEndDayOfMonth("2023-01-01",-1,true));
        System.out.println("当前月前一月的结束"+getStartOrEndDayOfMonth("2023-01-01",-1,false));
        System.out.println();
        System.out.println();
        System.out.println("当前季度的开始"+getStartOrEndDayOfQuarter("2023-01-01",0,true));
        System.out.println("当前季度的结束"+getStartOrEndDayOfQuarter("2023-01-01",0,false));
        System.out.println("当前季度前一季度的开始"+getStartOrEndDayOfQuarter("2023-01-01",-1,true));
        System.out.println("当前季度前一季度的结束"+getStartOrEndDayOfQuarter("2023-01-01",-1,false));
        System.out.println();
        System.out.println();
        System.out.println("当前年的开始"+getStartOrEndDayOfYear("2023-01-01",0,true));
        System.out.println("当前年的结束"+getStartOrEndDayOfYear("2023-01-01",0,false));
        System.out.println("当前年前一年的开始"+getStartOrEndDayOfYear("2023-01-01",-1,true));
        System.out.println("当前年前一年的结束"+getStartOrEndDayOfYear("2023-01-01",-1,false));
        //默认时间
       System.out.println("当前天的开始"+getStartOrEndDayOfDay(LocalDate.now(),0,true));
        System.out.println("当前天的结束"+getStartOrEndDayOfDay(LocalDate.now(),0,false));
        System.out.println("当前天前一天的开始"+getStartOrEndDayOfDay(LocalDate.now(),-1,true));
        System.out.println("当前天前一天的结束"+getStartOrEndDayOfDay(LocalDate.now(),-1,false));
        System.out.println();
        System.out.println();
        System.out.println("当前周的开始"+getStartOrEndDayOfWeek(LocalDate.now(),0,true));
        System.out.println("当前周的结束"+getStartOrEndDayOfWeek(LocalDate.now(),0,false));
        System.out.println("当前周前一周的开始"+getStartOrEndDayOfWeek(LocalDate.now(),-1,true));
        System.out.println("当前周前一周的结束"+getStartOrEndDayOfWeek(LocalDate.now()",-1,false));
        System.out.println();
        System.out.println();
        System.out.println("当前月的开始"+getStartOrEndDayOfMonth(LocalDate.now(),0,true));
        System.out.println("当前月的结束"+getStartOrEndDayOfMonth(LocalDate.now(),0,false));
        System.out.println("当前月前一月的开始"+getStartOrEndDayOfMonth(LocalDate.now(),-1,true));
        System.out.println("当前月前一月的结束"+getStartOrEndDayOfMonth(LocalDate.now(),-1,false));
        System.out.println();
        System.out.println();
        System.out.println("当前季度的开始"+getStartOrEndDayOfQuarter(LocalDate.now(),0,true));
        System.out.println("当前季度的结束"+getStartOrEndDayOfQuarter(LocalDate.now(),0,false));
        System.out.println("当前季度前一季度的开始"+getStartOrEndDayOfQuarter(LocalDate.now(),-1,true));
        System.out.println("当前季度前一季度的结束"+getStartOrEndDayOfQuarter(LocalDate.now(),-1,false));
        System.out.println();
        System.out.println();
        System.out.println("当前年的开始"+getStartOrEndDayOfYear(LocalDate.now(),0,true));
        System.out.println("当前年的结束"+getStartOrEndDayOfYear(LocalDate.now(),0,false));
        System.out.println("当前年前一年的开始"+getStartOrEndDayOfYear(LocalDate.now(),-1,true));
        System.out.println("当前年前一年的结束"+getStartOrEndDayOfYear(LocalDate.now(),-1,false));
    }

    /**
     * 获取天 第一天或最后一天
     * @param weeks 0本周，1下周，-1上周 以此类推
     * @param isFirst true获取开始时间 false获取结束时间
     * @return java.lang.String
     */
    public static String getStartOrEndDayOfDay(String today,long weeks, Boolean isFirst){
        LocalDate time = LocalDate.parse(today, DateTimeFormatter.ofPattern("yyyy-MM-dd"));
        LocalDate resDate = time.plusDays(weeks);
        String date;
        if (isFirst) {
             date =LocalDate.of(resDate.getYear(),resDate.getMonth(),resDate.getDayOfMonth())+min;
        } else {
             date =LocalDate.of(resDate.getYear(),resDate.getMonth(),resDate.getDayOfMonth())+max;
        }
        return date;
    }


    /**
     * 获取周 第一天或最后一天
     * @param weeks 0本周，1下周，-1上周 以此类推
     * @param isFirst true获取开始时间 false获取结束时间
     * @return java.lang.String
     */
    public static String getStartOrEndDayOfWeek(String today,long weeks, Boolean isFirst){
        LocalDate time = LocalDate.parse(today, DateTimeFormatter.ofPattern("yyyy-MM-dd"));
        LocalDate resDate = time.plusWeeks(weeks);
        DayOfWeek week = resDate.getDayOfWeek();
        int value = week.getValue();
        String date;
        if (isFirst) {
            date =resDate.minusDays(value - 1)+min;
        } else {
            date =resDate.plusDays(7 - value)+max;
        }
        return date;
    }


    /**
     * 获取月份 第一天或最后一天
     * @param months 0本月，1下月，-1上月 以此类推
     * @param isFirst true获取开始时间 false获取结束时间
     * @return java.lang.String
     */
    public static String getStartOrEndDayOfMonth(String today,long months, Boolean isFirst){
        LocalDate time = LocalDate.parse(today, DateTimeFormatter.ofPattern("yyyy-MM-dd"));
        LocalDate resDate = time.plusMonths(months);
        Month month = resDate.getMonth();
        int length = month.length(resDate.isLeapYear());
        String date;
        if (isFirst) {
            date =LocalDate.of(resDate.getYear(), month, 1)+min;
        } else {
            date =LocalDate.of(resDate.getYear(), month, length)+max;
        }
        return date;
    }




    /**
     * 获取季度 第一天或最后一天
     * @param quarters 0本季度，1下季度，-1上季度 以此类推
     * @param isFirst true获取开始时间 false获取结束时间
     * @return java.lang.String
     */
    public static String getStartOrEndDayOfQuarter(String today,long quarters, Boolean isFirst){
        LocalDate time = LocalDate.parse(today, DateTimeFormatter.ofPattern("yyyy-MM-dd"));
        LocalDate resDate = time.plusMonths(quarters * 3);
        Month month = resDate.getMonth();
        Month firstMonthOfQuarter = month.firstMonthOfQuarter();
        Month endMonthOfQuarter = Month.of(firstMonthOfQuarter.getValue() + 2);
        String date;
        if (isFirst) {
            date =LocalDate.of(resDate.getYear(), firstMonthOfQuarter, 1)+min;
        } else {
            date =LocalDate.of(resDate.getYear(), endMonthOfQuarter, endMonthOfQuarter.length(resDate.isLeapYear()))+max;
        }
        return date;
    }



    /**
     * 获取年份 第一天或最后一天
     * @param years 0本今年，1明年，-1去年 以此类推
     * @param isFirst true获取开始时间 false获取结束时间
     * @return java.lang.String
     */
    public static String getStartOrEndDayOfYear(String today,long years, Boolean isFirst){
        LocalDate time = LocalDate.parse(today, DateTimeFormatter.ofPattern("yyyy-MM-dd"));
        LocalDate resDate = time.plusYears(years);
        String date;
        if (isFirst) {
            date = LocalDate.of(resDate.getYear(), Month.JANUARY, 1)+min;;
        } else {
            date = LocalDate.of(resDate.getYear(), Month.DECEMBER, Month.DECEMBER.length(resDate.isLeapYear()))+max;
        }
        return date;
    }