java获取本月最后一天

java获取本月第一天或者最后一天方法

@Test
    public void lastDayOfMonth(){
        //LocalDate localDate = LocalDate.now();
        LocalDate localDate =LocalDate.of(2020, 2, 20);
        System.out.println("localDate = " + localDate);
        //当月最后一天
        LocalDate lastDay = localDate.with(TemporalAdjusters.lastDayOfMonth());
        System.out.println("lastDay = " + lastDay);
        //当月第一天
        LocalDate firstDay = localDate.with(TemporalAdjusters.firstDayOfMonth());
        System.out.println("firstDay = " + firstDay);
    }

Java8日期工具类：获取周、季和年的第一天和最后一天

public class DateUtil {

    private static final SimpleDateFormat sdf = new SimpleDateFormat("yyyy/MM/dd");

    /**
     * 格式化日期为指定的日期格式
     * @param date 时间参数
     * @return 时间毫秒数
     */
    public static String parseData(Date date){
        return sdf.format(date);
    }

    /**
     * 格式化当前日期为指定的日期格式
     * @return 时间毫秒数
     */
    public static String parseNowData(){
        return parseData(new Date());
    }

    /**
     * 获取本月的日期第一天
     * @return date
     */
    public static Date getFirstDayOfMonth(){
        return getFirstDayOfMonth(new Date());
    }

    /**
     * 获取某个时间所在月的日期第一天
     * @param date  日期
     * @return  时间毫秒数
     */
    public static Date getFirstDayOfMonth(Date date){
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        calendar.set(Calendar.DAY_OF_MONTH, calendar.getActualMinimum(Calendar.DAY_OF_MONTH));
        return calendar.getTime();
    }

    /**
     * 获取本月日期的最后一天
     * @return 时间毫秒数
     */
    public static Date getLastDayOfMonth(){
        return getLastDayOfMonth(new Date());
    }

    /**
     * 获取某个时间所在月的日期第一天
     * @param date 日期
     * @return 时间毫秒数
     */
    public static Date getLastDayOfMonth(Date date){
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        calendar.set(Calendar.DAY_OF_MONTH, calendar.getActualMaximum(Calendar.DAY_OF_MONTH));
        return calendar.getTime();
    }

    /**
     * 获取当前季度的第一天
     * @return 时间毫秒数
     */
    public static Date getFirstDayOfQuarter(){
        return getFirstDayOfQuarter(new Date());
    }

    /**
     * 获取时间所在季度的第一天
     * @param date 日期
     * @return 时间毫秒数
     */
    public static Date getFirstDayOfQuarter(Date date){
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        int remainder = calendar.get(Calendar.MONTH)  % 3;
        int month = remainder != 0 ? calendar.get(Calendar.MONTH) - remainder: calendar.get(Calendar.MONTH);
        calendar.set(Calendar.MONTH, month);
        calendar.set(Calendar.DAY_OF_MONTH, calendar.getActualMinimum(Calendar.DAY_OF_MONTH));
        return calendar.getTime();
    }

    /**
     * 获取当前季度的最后一天
     * @return 时间毫秒数
     */
    public static Date getLastDayOfQuarter(){
        return getLastDayOfQuarter(new Date());
    }

    /**
     * 获取时间所在季度的最后一天
     * @param date 日期
     * @return 时间毫秒数
     */
    public static Date getLastDayOfQuarter(Date date){
        Calendar calendar = Calendar.getInstance();
        calendar.setTime(date);
        int remainder = (calendar.get(Calendar.MONTH) + 1) % 3;
        int month = remainder != 0 ? calendar.get(Calendar.MONTH) + (3 - remainder) : calendar.get(Calendar.MONTH);
        calendar.set(Calendar.MONTH, month);
        calendar.set(Calendar.DAY_OF_MONTH, calendar.getActualMaximum(Calendar.DAY_OF_MONTH));
        return calendar.getTime();
    }

    /**
     * 获取当前年份的第一天
     * @return 时间毫秒数
     */
    public static Date getFirstDayOfYear(){
        return getFirstDayOfYear(new Date());
    }

    /**
     * 获取时间所在年份的第一天
     * @param date 日期
     * @return 时间毫秒数
     */
    public static Date getFirstDayOfYear(Date date){
        Calendar currCal=Calendar.getInstance();
        Calendar calendar = Calendar.getInstance();
        calendar.clear();
        currCal.setTime(date);
        calendar.set(Calendar.YEAR,currCal.get(Calendar.YEAR));
        return calendar.getTime();
    }

    /**
     * 获取当前年份的最后一天
     * @return 时间毫秒数
     */
    public static Date getLastDayOfYear(){
        return getLastDayOfYear(new Date());
    }

    /**
     * 获取时间所在年份的最后一天
     * @param date 日期
     * @return 时间毫秒数
     */
    public static Date getLastDayOfYear(Date date){
        Calendar currCal= Calendar.getInstance();
        Calendar calendar = Calendar.getInstance();
        calendar.clear();
        currCal.setTime(date);
        calendar.set(Calendar.YEAR,currCal.get(Calendar.YEAR));
        calendar.roll(Calendar.DAY_OF_YEAR,-1);
        return calendar.getTime();
    }

}