java处理日期的工具类

/**
 * 处理日期的工具类
 */
@Slf4j
public class DateUtils {

	/**
	 * <p>将字符串日期转换为Date</p>
	 */
	public static Date convertToDate(String s) {
		DateFormat df;
		if (s == null) {
			return null;
		}
		if (s.contains(":")) {
			try {
				df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
				return df.parse(s);
			} catch (Exception e) {
				log.error(e.getMessage());
			}
		} else {
			try {
				df = new SimpleDateFormat("yyyy-MM-dd");
				return df.parse(s);
			} catch (Exception e) {
				log.error(e.getMessage());
			}
		}
		return null;
	}

	/**
	 * <p>将Date转换为String(格式：yyyy-MM-dd)</p>
	 */
	public static String formatDate(Date d) {
		if (d == null) {
			return null;
		}

		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
		try {
			return sdf.format(d);
		} catch (Exception e) {
			log.error(e.getMessage());
		}

		return null;
	}

	/**
	 * <p>将Date转换为String(格式：yyyyMMdd)</p>
	 */
	public static String formatDateString(Date d) {
		if (d == null) {
			return null;
		}

		SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMdd");
		try {
			return sdf.format(d);
		} catch (Exception e) {
			log.error(e.getMessage());
		}

		return null;
	}

	public static Date strToYYMMDDDate(String dateString){
		if(null == dateString) {
			return new Date();
		}

		try {
			return new SimpleDateFormat("yyyy-MM-dd").parse(dateString);
		} catch (ParseException e) {
			return new Date();
		}
	}
	/**
	 * <p>获取当前时间戳</p>
	 */
	public static String getTimeStamp() {
		SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddHHmmssSSS");

		try {
			return sdf.format(new java.util.Date());
		} catch (Exception e) {
			log.error(e.getMessage());
		}

		return null;
	}

	/**
	 * <p>将Date转换为String(格式：yyyy-MM-dd HH:mm:ss)</p>
	 */
	public static String formatDateTime(Date d) {
		if (d == null) {
			return null;
		}

		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

		try {
			return sdf.format(d);
		} catch (Exception e) {
			log.error(e.getMessage());
		}

		return null;
	}

	/**
	 * <p>将Date转换为String(格式：yyyy-MM-dd HH:mm:ss)</p>
	 */
	public static String formatDateTime(Date d,String format) {
		if (d == null) {
			return null;
		}

		SimpleDateFormat sdf = new SimpleDateFormat(format);

		try {
			return sdf.format(d);
		} catch (Exception e) {
			log.error(e.getMessage());
		}

		return null;
	}

	/**
	 * <p>将Date按locale转换为String(格式：yyyy-MM-dd)</p>
	 */
	public static String formatLocaleDate(Date d, Locale locale) {
		if (d == null) {
			return null;
		}

		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd", locale);
		try {
			return sdf.format(d);
		} catch (Exception e) {
			log.error(e.getMessage());
		}

		return null;
	}

	/**
	 * <p>将Date按locale转换为String(格式：yyyy-MM-dd HH:mm:ss)</p>
	 */
	public static String formatLocaleDateTime(Date d, Locale locale) {
		if (d == null) {
			return null;
		}
		SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss", locale);
		try {
			return sdf.format(d);
		} catch (Exception e) {
			log.error(e.getMessage());
			return null;
		}
	}

	/**
	 * <p>得到每月多少天</p>
	 */
	public static int getDaysByMonth(int year, int month) {
		if (month == 1 || month == 3 || month == 5 || month == 7 || month == 8 || month == 10 || month == 12) {
			return 31;
		}

		if (month == 4 || month == 6 || month == 9 || month == 11) {
			return 30;
		}

		if (month == 2) {
			if ((year % 4 == 0 && year % 100 != 0) || year % 400 == 0) {
				return 29;
			} else {
				return 28;
			}
		}

		return -1;
	}

	/**
	 * <p>把星期的数字转换成汉字</p>
	 * 1：周日，2:周一.....7:周六
	 */
	public static String dayOfWeekByDayNum(int x) {
		String str = "星期日";
		if (x == 7) {
			str = "星期六";
		} else if (x == 6) {
			str = "星期五";
		} else if (x == 5) {
			str = "星期四";
		} else if (x == 4