根据当前日期，获取其他日期

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;

public class DateUtil {


    /**
     * 获取当前年份的第一天
     *
     * @return
     */
    public static String getFirstDateOfYear() {
        Calendar calendar = Calendar.getInstance();
        calendar.set(Calendar.MONTH, calendar.getActualMinimum(Calendar.MONTH));
        calendar.set(Calendar.DAY_OF_MONTH, calendar.getActualMinimum(Calendar.DAY_OF_MONTH));
        return new SimpleDateFormat("yyyy-MM-dd").format(calendar.getTime());
    }

    /**
     * 获取当前年份的最后一天
     *
     * @return
     */
    public static String getLastDateOfYear() {
        Calendar calendar = Calendar.getInstance();
        calendar.set(Calendar.MONTH, calendar.getActualMaximum(Calendar.MONTH));
        calendar.set(Calendar.DAY_OF_MONTH, calendar.getActualMaximum(Calendar.DAY_OF_MONTH));
        return new SimpleDateFormat("yyyy-MM-dd").format(calendar.getTime());
    }

    /**
     * 获取本月第一天
     *
     * @return
     */
    public static String getFirstDateOfMonth() {
        Calendar calendar = Calendar.getInstance();
        calendar.set(Calendar.DAY_OF_MONTH, calendar.getActualMinimum(Calendar.DAY_OF_MONTH));
        return new SimpleDateFormat("yyyy-MM-dd").format(calendar.getTime());
    }

    /**
     * 获取本月最后一天
     *
     * @return
     */
    public static String getLastDateOfMonth() {
        Calendar calendar = Calendar.getInstance();
        calendar.set(Calendar.DAY_OF_MONTH, calendar.getActualMaximum(Calendar.DAY_OF_MONTH));
        return new SimpleDateFormat("yyyy-MM-dd").format(calendar.getTime());
    }

    /**
     * 获取当天开始时间
     *
     * @return
     */
    public static Date getDayBegin() {
        Calendar todayStart = Calendar.getInstance();
        todayStart.set(Calendar.SECOND, 0);
        todayStart.set(Calendar.MINUTE, 0);
        todayStart.set(Calendar.HOUR_OF_DAY, 0);
        todayStart.set(Calendar.MILLISECOND, 0);
        return todayStart.getTime();
    }

    /**
     * 获取当天结束时间
     *
     * @return
     */
    public static Date getDayEnd() {
        Calendar todayEnd = Calendar.getInstance();
        todayEnd.set(Calendar.SECOND, 59);
        todayEnd.set(Calendar.MINUTE, 59);
        todayEnd.set(Calendar.HOUR_OF_DAY, 23);
        todayEnd.set(Calendar.MILLISECOND, 999);
        return todayEnd.getTime();
    }

}