1、获取某年开始时间和结束时间

//获取某年开始时间
public static LocalDateTime getBeginDayOfYear(String date) {
    LocalDate today;
    if (null==date){
        today = LocalDate.now();
    }else {
        DateTimeFormatter fmt = DateTimeFormatter.ofPattern("yyyy-MM-dd");
        today=LocalDate.parse(date, fmt);
    }
    today = LocalDate.of(today.getYear(), Month.JANUARY, 1);
    return today.atTime(00,00,01);
}

//获取某年结束时间
public static LocalDateTime getEndDayOfYear(String date) {
    LocalDate today;
    if (null==date){
        today = LocalDate.now();
    }else {
        DateTimeFormatter fmt = DateTimeFormatter.ofPattern("yyyy-MM-dd");
        today=LocalDate.parse(date, fmt);
    }
    today = LocalDate.of(today.getYear(), Month.DECEMBER, Month.DECEMBER.length(today.isLeapYear()));
    return today.atTime(23,59,59);
}

2、获取某月开始时间和结束时间

//获取某月开始时间
public static Date getBeginDayOfMonth(String date) {
    LocalDate date2;
    if (null==date){
        date2=LocalDate.now();
    }else {
        DateTimeFormatter fmt = DateTimeFormatter.ofPattern("yyyy-MM-dd");
        date2=LocalDate.parse(date, fmt);
    }
    Calendar calendar = Calendar.getInstance();
    calendar.set(date2.getYear(), date2.getMonthValue()-1, 1);
    return getDayStartTime(calendar.getTime());
}

//获取某月结束时间
public static Date getEndDayOfMonth(String date) {
    LocalDate date2;
    if (null==date){
        date2=LocalDate.now();
    }else {
        DateTimeFormatter fmt = DateTimeFormatter.ofPattern("yyyy-MM-dd");
        date2=LocalDate.parse(date, fmt);
    }
    Calendar calendar = Calendar.getInstance();
    calendar.set(date2.getYear(), date2.getMonthValue()-1, 1);
    int day = calendar.getActualMaximum(5);
    calendar.set(date2.getYear(), date2.getMonthValue()-1, day);
    return getDayEndTime(calendar.getTime());
}

//--------公共方法-----------------------------------

//获取某个日期的开始时间
public static Timestamp getDayStartTime(Date d) {
    Calendar calendar = Calendar.getInstance();
    if(null != d) calendar.setTime(d);
    calendar.set(calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH),    calendar.get(Calendar.DAY_OF_MONTH), 0, 0, 0);
    calendar.set(Calendar.MILLISECOND, 0);
    return new Timestamp(calendar.getTimeInMillis());
}

//获取某个日期的结束时间
public static Timestamp getDayEndTime(Date d) {
    Calendar calendar = Calendar.getInstance();
    if(null != d) calendar.setTime(d);
    calendar.set(calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH),    calendar.get(Calendar.DAY_OF_MONTH), 23, 59, 59);
    calendar.set(Calendar.MILLISECOND, 999);
    return new Timestamp(calendar.getTimeInMillis());
}

3、获取某周开始时间和结束时间

//获取本周的开始时间
public static Date getBeginDayOfWeek() {
    Date date = new Date();
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    int dayofweek = cal.get(Calendar.DAY_OF_WEEK);
    if (dayofweek == 1) {
        dayofweek += 7;
    }
    cal.add(Calendar.DATE, 2 - dayofweek);
    return getDayStartTime(cal.getTime());
}
 

//获取本周的结束时间
public static Date getEndDayOfWeek(){
    Calendar cal = Calendar.getInstance();
    cal.setTime(getBeginDayOfWeek());
    cal.add(Calendar.DAY_OF_WEEK, 6);
    Date weekEndSta = cal.getTime();
    return getDayEndTime(weekEndSta);
}

//---------------公共方法------------------------

//获取某个日期的开始时间
public static Timestamp getDayStartTime(Date d) {
    Calendar calendar = Calendar.getInstance();
    if(null != d) calendar.setTime(d);
    calendar.set(calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH),    calendar.get(Calendar.DAY_OF_MONTH), 0, 0, 0);
    calendar.set(Calendar.MILLISECOND, 0);
    return new Timestamp(calendar.getTimeInMillis());
}

//获取某个日期的结束时间
public static Timestamp getDayEndTime(Date d) {
    Calendar calendar = Calendar.getInstance();
    if(null != d) calendar.setTime(d);
    calendar.set(calendar.get(Calendar.YEAR), calendar.get(Calendar.MONTH),    calendar.get(Calendar.DAY_OF_MONTH), 23, 59, 59);
    calendar.set(Calendar.MILLISECOND, 999);
    return new Timestamp(calendar.getTimeInMillis());
}

4、获取明天的开始时间和结束时间

//获取明天的开始时间
public static Date getBeginDayOfTomorrow() {
    Calendar cal = new GregorianCalendar();
    cal.setTime(getDayBegin());
    cal.add(Calendar.DAY_OF_MONTH, 1);

    return cal.getTime();
}

//获取明天的结束时间
public static Date getEndDayOfTomorrow() {
    Calendar cal = new GregorianCalendar();
    cal.setTime(getDayEnd());
    cal.add(Calendar.DAY_OF_MONTH, 1);
    return cal.getTime();
}

5、获取昨天的开始时间和结束时间

//获取昨天的开始时间
public static Date getBeginDayOfYesterday() {
    Calendar cal = new GregorianCalendar();
    cal.setTime(getDayBegin());
    cal.add(Calendar.DAY_OF_MONTH, -1);
    return cal.getTime();
}
 
//获取昨天的结束时间
public static Date getEndDayOfYesterDay() {
    Calendar cal = new GregorianCalendar();
    cal.setTime(getDayEnd());
    cal.add(Calendar.DAY_OF_MONTH, -1);
    return cal.getTime();
}

6、获取今天的开始时间和结束时间

//获取当天的开始时间
public static java.util.Date getDayBegin() {
    Calendar cal = new GregorianCalendar();
    cal.set(Calendar.HOUR_OF_DAY, 0);
    cal.set(Calendar.MINUTE, 0);
    cal.set(Calendar.SECOND, 0);
    cal.set(Calendar.MILLISECOND, 0);
    return cal.getTime();
}

//获取当天的结束时间
public static java.util.Date getDayEnd() {
    Calendar cal = new GregorianCalendar();
    cal.set(Calendar.HOUR_OF_DAY, 23);
    cal.set(Calendar.MINUTE, 59);
    cal.set(Calendar.SECOND, 59);
    return cal.getTime();
}

7、给时间加上几天/几小时/几分钟

/**
 * 1、返回String
 * 给时间date加上天数，小时，分钟
 * @param date   //原本时间
 * @param day    //要加的天数
 * @param hour   //要加的小时
 * @param minute //要加的分钟
 */
public static String addDateTime(Date date, int day, int hour, int minute) {
    SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    cal.add(Calendar.DATE, day);// 24小时制,加天
    cal.add(Calendar.HOUR, hour);// 24小时制 ,加小时
    cal.add(Calendar.MINUTE, minute);// 24小时制,加分钟
    date = cal.getTime();
    String str_date = format.format(date);
    return str_date;
}


/**
 * 2、返回date
 * 给时间date加上天数，小时，分钟
 * @param date   //需要加的时间
 * @param day    //要加的天数
 * @param hour   //要加的小时
 * @param minute //要加的分钟
 * 返回date
 */
public static Date addDateTime(Date date, int day, int hour, int minute) {
    Calendar cal = Calendar.getInstance();
    cal.setTime(date);
    cal.add(Calendar.DATE, day);// 24小时制,加天
    cal.add(Calendar.HOUR, hour);// 24小时制 ,加小时
    cal.add(Calendar.MINUTE, minute);// 24小时制,加分钟
    date = cal.getTime();
    return date;
}