java获取当年第一天

/**
* 当前月第一天
*
* @return 当前月第一天
*/
public String getThisMonth() {
// 获取前月的第一天
Calendar calendar = Calendar.getInstance();
SimpleDateFormat format = new SimpleDateFormat(“yyyy-MM-dd”);
calendar.add(Calendar.MONTH, 0);
calendar.set(Calendar.DAY_OF_MONTH, 1);// 设置为1号,当前日期既为本月第一天
String firstDay = format.format(calendar.getTime());
return firstDay;
}

/**
 * 日期是本月的第几天
 * 
 * @param date
 *            天
 * @return 当前天数
 * @throws ParseException
 *             数据转换异常
 */
public static String getMostDay(String date) throws ParseException {
    // 当天日期是本月的第几天
    SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
    Date nowDay = format.parse(date);
    Calendar ca = Calendar.getInstance();
    ca.setTime(nowDay);
    int num = ca.get(Calendar.DAY_OF_MONTH);
    String time = String.valueOf(num);
    return time;
}

/**
 * 获取日期在当月天数
 * 
 * @param date
 *            天
 * @return 当月天数
 * @throws Exception
 *             异常
 */
public static String getMonthDay(String date) throws Exception {
    // 当前月最大日期
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    Date dates = sdf.parse(date);// String-->Date
    Calendar calendar = Calendar.getInstance();
    calendar.setTime(dates);// 设置日历时间
    int day = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
    String mostDate = String.valueOf(day);
    return mostDate;
}

/**
 * 当年第一天
 * 
 * @param date
 *            日期
 * @return 天
 * @throws Exception
 *             异常
 */
public static String getThisYear(String date) throws Exception {
    SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
    SimpleDateFormat format3 = new SimpleDateFormat("yyyy");
    Date time = format3.parse(date);
    String time1 = format3.format(time);
    Date startTime = format.parse(time1 + "-01-01");
    String dates = format.format(startTime);
    return dates;
}

/**
 * 当月第一天
 * 
 * @param date
 *            天
 * @return 天
 * @throws ParseException
 *             异常
 */
public static String getFirstDayToMonth(String date) throws ParseException {
    // 获取截止当前天数
    SimpleDateFormat format = new SimpleDateFormat("yyyy-MM");
    Date nowDay = format.parse(date);
    String time = format.format(nowDay);
    String firstDay = time + "-01";
    return firstDay;
}

/**
 * 当年第一天
 * 
 * @param date
 *            天
 * @return 天
 * @throws ParseException
 *             异常
 */
public static String getFirstDay(String date) throws ParseException {
    // 获取截止当前天数
    SimpleDateFormat format = new SimpleDateFormat("yyyy");
    Date nowDay = format.parse(date);
    String time = format.format(nowDay);
    String firstDay = time + "-01-01";
    return firstDay;
}

/**
 * 获取日期到年初的天数
 * 
 * @param date
 *            天
 * @return 天数
 * @throws Exception
 *             异常
 */
public static int getDayCount(String date) throws Exception {
    // 获取截止当前天数
    SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");

    String year = date.substring(0, ConstantUtils.CUT_OUT);
    String starttime = year + "-01-01 00:00:00";
    String endtime = date + " 00:00:00";
    Date d1 = format.parse(starttime);
    Date d2 = format.parse(endtime);
    long s1 = d1.getTime();
    long s2 = d2.getTime();
    int days = (int) ((s2 - s1) / ConstantUtils.EVERYDAY_SECONF);
    return days;
}

/**
 * 月底到年初的天数
 * 
 * @param date
 *            天
 * @return 天
 * @throws Exception
 *             异常
 */
public static int getYearCount(String date) throws Exception {
    String count = getMonthDay(date);
    String firstDay = getFirstDay(date);
    SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
    SimpleDateFormat format2 = new SimpleDateFormat("yyyy-MM");
    long startTime = format.parse(firstDay).getTime();
    long endTime = format2.parse(date).getTime();
    String string = format2.format(endTime);
    Date dates = format.parse(string + "-" + count);
    long endMonthTime = dates.getTime();
    long dayMonth = (endMonthTime - startTime) / ConstantUtils.EVERYDAY_SECONF;
    return (int) dayMonth;
}


/**
 * 获取给定日起前一天
 * 
 * @param date
 *            天
 * @return 天
 * @throws ParseException
 *             异常
 */
public static String getYesterDay(String date) throws ParseException {
    // 获取给定日起过去15天
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    Calendar cal = Calendar.getInstance();
    Date dateTemp = sdf.parse(date);
    cal.setTime(dateTemp);
    cal.add(Calendar.DATE, ConstantUtils.MINUS_1);
    Date dates = cal.getTime();
    String yesterDay = sdf.format(dates);
    return yesterDay;
}

/**
 * 获取给定日起前一周
 * 
 * @param date
 *            天
 * @return 天
 * @throws ParseException
 *             异常
 */
public static String getLastWeekDay(String date) throws ParseException {
    // 获取给定日起过去15天
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    Calendar cal = Calendar.getInstance();
    Date dateTemp = sdf.parse(date);
    cal.setTime(dateTemp);
    cal.add(Calendar.DATE, ConstantUtils.MINUS_7);
    Date dates = cal.getTime();
    String yesterDay = sdf.format(dates);
    return yesterDay;
}

/**
 * 获取给定日起过去15天
 * 
 * @param date
 *            天
 * @return 天
 * @throws ParseException
 *             异常
 */
public static String getLastFifthDay(String date) throws ParseException {
    // 获取给定日起过去15天
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    Calendar cal = Calendar.getInstance();
    Date dateTemp = sdf.parse(date);
    cal.setTime(dateTemp);
    cal.add(Calendar.DATE, ConstantUtils.MINUS_15); // -15
    Date dates = cal.getTime();
    String lastFifthDay = sdf.format(dates);
    return lastFifthDay;
}

/**
 * 获取给定日起一个月
 * 
 * @param date
 *            天
 * @return 天
 * @throws ParseException
 *             异常
 */
public static String getLastMonthDay(String date) throws ParseException {
    // 获取给定日起过去15天
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    Calendar cal = Calendar.getInstance();
    Date dateTemp = sdf.parse(date);
    cal.setTime(dateTemp);
    cal.add(Calendar.MONTH, ConstantUtils.MINUS_1); // -1,1个月前
    Date dates = cal.getTime();
    String lastHalfYearDay = sdf.format(dates);
    return lastHalfYearDay;
}

/**
 * 获取给定日起3个月
 * 
 * @param date
 *            天
 * @return 天
 * @throws ParseException
 *             异常
 */
public static String getLastThreeMonthsDay(String date) throws ParseException {
    // 获取给定日起过去15天
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    Calendar cal = Calendar.getInstance();
    Date dateTemp = sdf.parse(date);
    cal.setTime(dateTemp);
    cal.add(Calendar.MONTH, ConstantUtils.MINUS_3); // -1,1个月前
    Date dates = cal.getTime();
    String lastHalfYearDay = sdf.format(dates);
    return lastHalfYearDay;
}

/**
 * 获取给定日起过去半年
 * 
 * @param date
 *            天
 * @return 天
 * @throws ParseException
 *             异常
 */
public static String getLasthalfYearDay(String date) throws ParseException {
    // 获取给定日起过去15天
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    Calendar cal = Calendar.getInstance();
    Date dateTemp = sdf.parse(date);
    cal.setTime(dateTemp);
    cal.add(Calendar.MONTH, ConstantUtils.MINUS_6); //-6,6个月前
    Date dates = cal.getTime();
    String lastHalfYearDay = sdf.format(dates);
    return lastHalfYearDay;
}

/**
 * 获取给定日去年同期
 * 
 * @param date
 *            天
 * @return 天
 * @throws ParseException
 *             异常
 */
public static String getToLastYearDay(String date) throws ParseException {
    // 获取给定日起过去15天
    SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd");
    Calendar cal = Calendar.getInstance();
    Date dateTemp = sdf.parse(date);
    cal.setTime(dateTemp);
    cal.add(Calendar.YEAR, -1);
    Date dates = cal.getTime();
    String toLastYearDay = sdf.format(dates);
    return toLastYearDay;
}