java得到某年某周的第一天

直接上代码

import java.util.Calendar;
import java.util.Date;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

/**
 * 日期工具类
 * @author WXQ
 *
 */
public class DateUtils {
	
	private static final Log log = LogFactory.getLog(DateUtils.class);

	/** 
	 * 取得当前日期是多少周 
	 * 
	 * @param date 
	 * @return 
	 */
	public static int getWeekOfYear(Date date) {
		Calendar c = Calendar.getInstance();
		c.setFirstDayOfWeek(Calendar.MONDAY);
		/**设置一年中第一个星期所需的最少天数，例如，如果定义第一个星期包含一年第一个月的第一天，则使用值 1 调用此方法。
		 * 如果最少天数必须是一整个星期，则使用值 7 调用此方法。 **/
		c.setMinimalDaysInFirstWeek(1);
		c.setTime(date);

		return c.get(Calendar.WEEK_OF_YEAR);
	}

	/** 
	 * 得到某一年周的总数 
	 * 
	 * @param year 
	 * @return 
	 */
	public static int getMaxWeekNumOfYear(int year) {
		Calendar c = Calendar.getInstance();
		c.set(year, Calendar.DECEMBER, 31, 23, 59, 59);

		return getWeekOfYear(c.getTime());
	}

	/** 
	 * 得到某年某周的第一天 
	 * 
	 * @param year 
	 * @param week 
	 * @return 
	 */
	public static Date getFirstDayOfWeek(int year, int week) {
		Calendar c = Calendar.getInstance();
		c.set(Calendar.YEAR, year);
		c.set(Calendar.WEEK_OF_YEAR, week);
		c.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);//设置周一
		c.setFirstDayOfWeek(Calendar.MONDAY);

		return c.getTime();
	}
	
	/** 
	 * 得到某年某周的最后一天 
	 * 
	 * @param year 
	 * @param week 
	 * @return 
	 */
	public static Date getLastDayOfWeek(int year, int week) {
		Calendar c = Calendar.getInstance();
		c.set(Calendar.YEAR, year);
		c.set(Calendar.WEEK_OF_YEAR, week);
		c.setFirstDayOfWeek(Calendar.MONDAY);
		c.set(Calendar.DAY_OF_WEEK, c.getFirstDayOfWeek() + 6); // Sunday 
		
		return c.getTime();
	}
	
	/** 
	 * 得到某年某月的第一天 
	 * 
	 * @param year 
	 * @param month 
	 * @return 
	 */
	public static Date getFirstDayOfMonth(int year, int month) {
		Calendar c = Calendar.getInstance();
		c.set(Calendar.YEAR, year);
		c.set(Calendar.MONTH, month-1);
		c.set(Calendar.DAY_OF_MONTH, c.getActualMinimum(Calendar.DAY_OF_MONTH));

		return c.getTime();
	}
	
	/** 
	 * 得到某年某月的最后一天 
	 * 
	 * @param year 
	 * @param month 
	 * @return 
	 */
	public static Date getLastDayOfMonth(int year, int month) {
		Calendar c = Calendar.getInstance();
		c.set(Calendar.YEAR, year);
		c.set(Calendar.MONTH, month-1);
		c.set(Calendar.DAY_OF_MONTH, c.getActualMaximum(Calendar.DAY_OF_MONTH));

		return c.getTime();
	}

	/**
	 * 得到某年某季度第一天
	 * 
	 * @param year
	 * @param quarter
	 * @return
	 */
	public static Date getFirstDayOfQuarter(int year, int quarter) {
		int month = 0;
		if (quarter > 4) {
			return null;
		} else {
			month = (quarter - 1) * 3 + 1;
		}
		return getFirstDayOfMonth(year, month);
	}

	/**
	 * 得到某年某季度最后一天
	 * 
	 * @param year
	 * @param quarter
	 * @return
	 */
	public static Date getLastDayOfQuarter(int year, int quarter) {
		int month = 0;
		if (quarter > 4) {
			return null;
		} else {
			month = quarter * 3;
		}
		return getLastDayOfMonth(year, month);
	}

	/**
	 * 得到某年第一天
	 * 
	 * @param year
	 * @return
	 */
	public static Date getFirstDayOfYear(int year) {
		return getFirstDayOfQuarter(year,1);
	}
	
	/**
	 * 得到某年最后一天
	 * 
	 * @param year
	 * @return
	 */
	public static Date getLastDayOfYear(int year) {
		return getLastDayOfQuarter(year,4);
	}
	
	public static void main(String[] args) {
		log.info(getFirstDayOfWeek(2013,1));
		log.info(getLastDayOfWeek(2013,1));
		
		log.info(getFirstDayOfMonth(2013,2));
		log.info(getLastDayOfMonth(2013,2));
		
		log.info(getFirstDayOfQuarter(2013,2));
		log.info(getLastDayOfQuarter(2013,2));
		
		log.info(getFirstDayOfYear(2013));
		log.info(getLastDayOfYear(2013));
		
	}
}