JAVA获取本周 本月 本年 第一天和最后一天

/**
 * 日期工具类
 */
public class DateUtils {
    /**
     * 获取今天
     * @return String
     * */
    public static String getToday(){
        return new SimpleDateFormat("yyyy-MM-dd").format(new Date());
    }

    /**
     * 获取昨天
     * @return String
     * */
    public static String getYestoday(){
        Calendar cal=Calendar.getInstance();
        cal.add(Calendar.DATE,-1);
        Date time=cal.getTime();
        return new SimpleDateFormat("yyyy-MM-dd").format(time);
    }

    /**
     * 获取本月开始日期
     * @return String
     * **/
    public static String getMonthStart(){
        Calendar cal=Calendar.getInstance();
        cal.add(Calendar.MONTH, 0);
        cal.set(Calendar.DAY_OF_MONTH, 1);
        Date time=cal.getTime();
        return new SimpleDateFormat("yyyy-MM-dd").format(time)+" 00:00:00";
    }

    /**
     * 获取本月最后一天
     * @return String
     * **/
    public static String getMonthEnd(){
        Calendar cal=Calendar.getInstance();
        cal.set(Calendar.DAY_OF_MONTH, cal.getActualMaximum(Calendar.DAY_OF_MONTH));
        Date time=cal.getTime();
        return new SimpleDateFormat("yyyy-MM-dd").format(time)+" 23:59:59";
    }

    /**
     * 获取本周的第一天
     * @return String
     * **/
    public static String getWeekStart(){
        Calendar cal=Calendar.getInstance();
        cal.add(Calendar.WEEK_OF_MONTH, 0);
        cal.set(Calendar.DAY_OF_WEEK, 2);
        Date time=cal.getTime();
        return new SimpleDateFormat("yyyy-MM-dd").format(time)+" 00:00:00";
    }

    /**
     * 获取本周的最后一天
     * @return String
     * **/
    public static String getWeekEnd(){
        Calendar cal=Calendar.getInstance();
        cal.set(Calendar.DAY_OF_WEEK, cal.getActualMaximum(Calendar.DAY_OF_WEEK));
        cal.add(Calendar.DAY_OF_WEEK, 1);
        Date time=cal.getTime();
        return new SimpleDateFormat("yyyy-MM-dd").format(time)+" 23:59:59";
    }

    /**
     * 获取本年的第一天
     * @return String
     * **/
    public static String getYearStart(){
        return new SimpleDateFormat("yyyy").format(new Date())+"-01-01";
    }
  
    /**
     * 获取本年的最后一天
     * @return String
     * **/
    public static String getYearEnd(){
        Calendar calendar = Calendar.getInstance();
        calendar.set(Calendar.MONTH,calendar.getActualMaximum(Calendar.MONTH));
        calendar.set(Calendar.DAY_OF_MONTH,calendar.getActualMaximum(Calendar.DAY_OF_MONTH));
        Date currYearLast = calendar.getTime();
        return new SimpleDateFormat("yyyy-MM-dd").format(currYearLast)+" 23:59:59";
    }
}