基于jdk8的日期时间计算工具类

以下是一个基于jdk8的日期时间计算工具类的示例代码：

import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.Period;
import java.time.format.DateTimeFormatter;

public class DateUtil {
    
    private static final DateTimeFormatter DATE_FORMAT = DateTimeFormatter.ofPattern("yyyy-MM-dd");
    private static final DateTimeFormatter TIME_FORMAT = DateTimeFormatter.ofPattern("HH:mm:ss");
    private static final DateTimeFormatter DATE_TIME_FORMAT = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss");
    
    public static String formatDate(LocalDate date) {
        return DATE_FORMAT.format(date);
    }
    
    public static String formatTime(LocalTime time) {
        return TIME_FORMAT.format(time);
    }
    
    public static String formatDateTime(LocalDateTime dateTime) {
        return DATE_TIME_FORMAT.format(dateTime);
    }
    
    public static LocalDate parseDate(String dateStr) {
        return LocalDate.parse(dateStr, DATE_FORMAT);
    }
    
    public static LocalTime parseTime(String timeStr) {
        return LocalTime.parse(timeStr, TIME_FORMAT);
    }
    
    public static LocalDateTime parseDateTime(String dateTimeStr) {
        return LocalDateTime.parse(dateTimeStr, DATE_TIME_FORMAT);
    }
    
    public static LocalDate addDays(LocalDate date, int days) {
        return date.plusDays(days);
    }
    
    public static LocalDateTime addHours(LocalDateTime dateTime, int hours) {
        return dateTime.plusHours(hours);
    }
    
    public static LocalDateTime addMinutes(LocalDateTime dateTime, int minutes) {
        return dateTime.plusMinutes(minutes);
    }
    
    public static LocalDateTime addSeconds(LocalDateTime dateTime, int seconds) {
        return dateTime.plusSeconds(seconds);
    }
    
    public static Period getPeriod(LocalDate startDate, LocalDate endDate) {
        return Period.between(startDate, endDate);
    }
    
    public static long getSeconds(LocalDateTime startDateTime, LocalDateTime endDateTime) {
        return startDateTime.until(endDateTime, java.time.temporal.ChronoUnit.SECONDS);
    }
    
    public static long getMinutes(LocalDateTime startDateTime, LocalDateTime endDateTime) {
        return startDateTime.until(endDateTime, java.time.temporal.ChronoUnit.MINUTES);
    }
    
    public static long getHours(LocalDateTime startDateTime, LocalDateTime endDateTime) {
        return startDateTime.until(endDateTime, java.time.temporal.ChronoUnit.HOURS);
    }
    
    public static long getDays(LocalDate startDate, LocalDate endDate) {
        return startDate.until(endDate, java.time.temporal.ChronoUnit.DAYS);
    }
    
}

这个工具类包含了日期时间格式化、解析、加减、差值计算等常用操作。使用该工具类可以方便地处理日期时间计算相关的业务需求。