轮子：DateUtil.java

日期工具类

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

public class DateUtil {

	public static final String DATE = "yyyy/MM/dd";

	public static final String Date = "yyyy-MM-dd";

	public static final String TIME = "HH:mm:ss";

	public static final String DATE_TIME = "yyyy/MM/dd HH:mm:ss";

	public static final String Date_TIME = "yyyy-MM-dd HH:mm:ss";

	public static final String DateTime = "yyyyMMddHHmmss";

	/**
	 * 自定义时间格式化
	 * @param date
	 * @param simpleDateFormat
	 * @return
	 */
	public static String customFormat(Date date, String simpleDateFormat){
		SimpleDateFormat sdf = new SimpleDateFormat(simpleDateFormat);
		return sdf.format(date);
	}

	/**
	 * 获取当前时间  yyyy-MM-dd HH:mm:ss
	 * @return 字符类型时间
	 */
	public static String nowFormatStr(){
		return customFormat(new Date(), Date_TIME);
	}

	/**
	 * 获取当前时间  yyyyMMddHHmmss
	 * @return 字符类型时间
	 */
	public static String nowFormatStrTwo(){
		return customFormat(new Date(), DateTime);
	}

	/**
	 * 判断日期大小
	 * 前者小 返回-1
	 * 前者大 返回1
	 * 相等 返回0
	 * @param date1
	 * @param date2
	 * @return
	 */
	public static int compareTo(Date date1, Date date2){
		return date1.compareTo(date2);
	}

	/**
	 * 判断与当前时间戳的相差的毫秒数
	 * @return
	 */
	public static long timestampDifferByNow(long timestamp){
		long millis = System.currentTimeMillis();
		return Math.abs(timestamp-millis);
	}

	/**
	 * 判断指定的时间戳与当前时间是否超时
	 * @param timestamp
	 * @param second 在有效期内的秒数
	 * @return
	 */
	public static boolean judgeTimeOutBySecond(long timestamp, long second){
		long differ = timestampDifferByNow(timestamp);
		return differ/1000 >= second;
	}

	/**
	 * 判断指定的时间戳与当前时间是否超时
	 * @param timestamp
	 * @param MS 毫秒
	 * @return
	 */
	public static boolean judgeTimeOutByMS(long timestamp, long MS){
		long differ = timestampDifferByNow(timestamp);
		return differ >= MS;
	}

	/**
	 * 获取两个Date之间相差的天数
	 * @param begintime
	 * @param endtime
	 * @return
	 */
	public static Double getDaysDiffer(Date begintime, Date endtime) {
		long time01 = begintime.getTime();
		long time02 = endtime.getTime();
		long diff = Math.abs(time01 - time02)/1000;
		return diff / 86400.0;
	}

	/**
	 * 获取两个Date之间相差的天数（向上取整）
	 * @param begintime
	 * @param endtime
	 * @return
	 */
	public static Integer getDaysCeilDiffer(Date begintime, Date endtime) {
		Double days = getDaysDiffer(begintime, endtime);
		return Double.valueOf(Math.ceil(days)).intValue();
	}

	/**
	 * 获取两个Date之间相差的天数（向下取整）
	 * @param begintime
	 * @param endtime
	 * @return
	 */
	public static Integer getDaysFloorDiffer(Date begintime, Date endtime) {
		Double days = getDaysDiffer(begintime, endtime);
		return Double.valueOf(Math.floor(days)).intValue();
	}

}

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