package cn.com.free.util;

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

public class DateUtil {

	/**
	 * 取得当前年份
	 * 
	 * @author zbq
	 * @date 2010-01-29
	 */
	public static String getCurrentYear(){
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy");
        Date date = new Date();
        return sdf.format(date);
	}
	
	/**
	 * 取得年月日时分秒
	 * 
	 * @author zbq
	 * @date 2010-01-29
	 */
	public static String getCurrentTime(){
        SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
        Date date = new Date();
        return sdf.format(date);
	}
	
	/**
	 * 取得年月日时分秒
	 * 
	 * @author zbq
	 * @date 2010-01-29
	 */
	public static String getYmdSfm(){
        SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddHHmmss");
        Date date = new Date();
        return sdf.format(date);
	}
	
	/**
	 * 取得当前日期字符串
	 * 
	 * @return YYYYMMDD(例:20110829)
	 * 
	 * @Author zbq
	 * @Date 2011-8-30
	 */
	public static String getTodayYmd() {
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
        Date date = new Date();
        return sdf.format(date);
	}
	
	/**
	 * 取得一周日期
	 * 
	 * @author zbq
	 * @date 2010-01-29
	 */
	public static List<String> getDateToWeek(Date date){
		List<String> dateWeekList = new ArrayList<String>();
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
		String time = "";
		//flag用来存取与当天日期的相差数
		int flag = 0;
		for(int i=1;i<8;i++){
			//新建日历
			Calendar cal = Calendar.getInstance();
			//在日历中找到当前日期
			cal.setTime(date);
			//当前日期时本周第几天，默认按照西方惯例上周星期天为第一天
			flag = -cal.get(Calendar.DAY_OF_WEEK);
			//根据循环。当天与上周星期天和本周一到周五相差的天数
			cal.add(Calendar.DATE, flag+i);
			//转化格式
			time = sdf.format(cal.getTime());
			//存入list
			dateWeekList.add(time);
		}
		return dateWeekList;	
	}
	
	/**
	 * 两个日期比较
	 * 
	 * @return 比较结果0为相等、小于0为前小于后，大于0为前大于后
	 * 
	 * @Author zbq
	 * @Date 2011-8-30
	 */
	public static int getDateTimeCompare(String dateStrStart,String dateStrEnd) {
		Calendar c1 = Calendar.getInstance();
		Calendar c2 = Calendar.getInstance();
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
		try {
			c2.setTime(sdf.parse(dateStrEnd));
			c1.setTime(sdf.parse(dateStrStart));
		} catch (java.text.ParseException e) {
			
		}
		int result = c1.compareTo(c2);
		return result;
	}
}