Java编程时间日期API实例解析

本文实例主要是关于Java8中的新特性，时间日期api的相关实例，具体如下：

package com.effective.common.base.date;
import java.time.Instant;
import java.time.LocalDate;
import java.time.LocalDateTime;
import java.time.LocalTime;
import java.time.Period;
import java.time.ZoneId;
import java.time.format.DateTimeFormatter;
import java.time.temporal.ChronoUnit;
import java.util.Date;
/**
 * 日期工具类
 * @author yanweiqi
 * @since 2016-5-6
 *
 */
public class LocalDateUtils {
    private static ZoneId zone = ZoneId.systemDefault();
    /**
   * 字符串转Date
   * @param date
   * @return
   * @throws Exception
   */
    public static Date convertToDate(String date) throws Exception{
        LocalDate localDate = null;
        if(null == date){
            throw new NullPointerException("date isn't null");
        } else {
            localDate = LocalDate.parse(date);
            return convertToDate(localDate);
        }
    }
    /**
   * 字符串转LocalDateTime
   * @param date
   * @return localDateTime
   */
    public static LocalDateTime convertToLocalDateTime(String date){
        LocalDateTime localDateTime = null;
        if(null == date){
            throw new NullPointerException("date isn't null");
        } else {
            localDateTime = LocalDateTime.parse(date);
            return localDateTime;
        }
    }
    /**
   * LocalDate转Date
   * @param localDate
   * @return Date
   */
    public static Date convertToDate(LocalDate localDate){
        Instant instant = localDate.atStartOfDay().atZone(zone).toInstant();
        return Date.from(instant);
    }
    /**
   * LocalDate转Date
   * @param localDateTime
   * @return Date
   */
    public static Date convertToDate(LocalDateTime localDateTime){
        Instant instant = localDateTime.atZone(zone).toInstant();
        return Date.from(instant);
    }
    /**
   * Date转LocalDate
   * @param date
   * @return localDate
   */
    public static LocalDate convertToLocalDate(Date date){
        Instant instant = date.toInstant();
        return convertToLocalDateTime(instant).toLocalDate();
    }
    /**
   * Date转LocalTime
   * @param date
   * @return localDate
   */
    public static LocalTime convertToLocalTime(Date date){
        Instant instant = date.toInstant();
        return convertToLocalDateTime(instant).toLocalTime();
    }
    /**
   * Date转LocalDatetime
   * @param date
   * @return localDate
   */
    public static LocalDateTime convertToLocalDateTime(Date date){
        Instant instant = date.toInstant();
        return convertToLocalDateTime(instant);
    }
    /**
   * Instant转LocalDateTime
   * @param instant
   * @return
   */
    public static LocalDateTime convertToLocalDateTime(Instant instant){
        return LocalDateTime.ofInstant(instant, zone);
    }
    /**
   * LocalDateTime转Instant
   * @param localDateTime
   * @return
   */
    public static Instant convertToInstant(LocalDateTime localDateTime){
        return localDateTime.atZone(zone).toInstant();
    }
    /**
   * LocalDate转Instant
   * @param localDate
   * @return
   */
    public static Instant convertToInstant(LocalDate localDate){
        return localDate.atStartOfDay(zone).toInstant();
    }
    /**
   * LocalDate转LocalDateTime
   * @param localDate
   * @return LocalDateTime
   */
    public static LocalDateTime convertToLocalDateTime(LocalDate localDate){
        return localDate.atStartOfDay();
    }
    /**
   * 日周期格式化
   * @param localDateTime
   * @param formatStyle
   * @return
   */
    public static String formatter(LocalDateTime localDateTime, String formatStyle){
        return DateTimeFormatter.ofPattern(formatStyle).format(localDateTime);
    }
    /**
   * 设置年
   * @param sourceDate
   * @param year
   * @return LocalDateTime
   */
    public static LocalDateTime setYear(LocalDateTime sourceDate, Integer year){
        return sourceDate.withYear(year);
    }
    /**
   * 设置月
   * @param sourceDate
   * @param month
   * @return LocalDateTime
   */
    public static LocalDateTime setMonth(LocalDateTime sourceDate, Integer month){
        return sourceDate.withMonth(month);
    }
    /**
   * 设置天
   * @param sourceDate
   * @param month
   * @return LocalDateTime
   */
    public static LocalDateTime setDayOfMonth(LocalDateTime sourceDate, Integer dayOfMonth){
        return sourceDate.withDayOfMonth(dayOfMonth);
    }
    /**
   * 设置小时
   * @param sourceDate
   * @param hour
   * @return
   */
    public static LocalDateTime setHour(LocalDateTime sourceDate,Integer hour){
        return sourceDate.withHour(hour);
    }
    /**
   * 设置分钟
   * @param sourceDate
   * @param minute
   * @return
   */
    public static LocalDateTime setMinute(LocalDateTime sourceDate,Integer minute){
        return sourceDate.withMinute(minute);
    }
    /**
   * 设置秒
   * @param sourceDate
   * @param second
   * @return
   */
    public static LocalDateTime setSecond(LocalDateTime sourceDate,Integer second){
        return sourceDate.withSecond(second);
    }
    /**
   * 修改年月日
   * @param sourceDate
   * @param year
   * @param month
   * @param dayOfMonth
   * @return
   */
    public static LocalDateTime setYMD(LocalDateTime sourceDate, Integer year, Integer month, Integer dayOfMonth) {
        return sourceDate.withYear(year).withMonth(month).withDayOfMonth(dayOfMonth);
    }
    /**
   * 修改时分秒
   * @param sourceDate
   * @param hour
   * @param minute
   * @param second
   * @return
   */
    public static LocalDateTime setHMS(LocalDateTime sourceDate,Integer hour, Integer minute, Integer second) {
        return sourceDate.withHour(hour).withMinute(minute).withSecond(second);
    }
    /**
   * 计算相差的天数
   * @param beginDate
   * @param endDate
   * @return
   */
    public static int getInteverDays(LocalDate beginDate,LocalDate endDate){
        Period period = Period.between(beginDate, endDate);
        return period.getDays();
    }
    /**
   * 日期加减
   * @param num 数量
   * @param unit 单位
   * @param LocalDate 原日期
   * @return LocalDate 增加后的日期
   */
    @SuppressWarnings("static-access")
      public static LocalDate addLocalDate(long num,ChronoUnit unit,final LocalDate localDate){
        LocalDate resultDate;
        if(num > 0){
            resultDate = localDate.now().plus(num, unit);
        } else {
            resultDate = localDate.now().minus(Math.abs(num), unit);
        }
        return resultDate;
    }
    /**
   * 日期时分秒加
   * @param num 数量
   * @param unit 单位
   * @param localDateTime 原日期
   * @return LocalDateTime 增加后的日期
   */
    @SuppressWarnings("static-access")
      public static LocalDateTime addLocalDateTime(long num,ChronoUnit unit,LocalDateTime localDateTime){
        LocalDateTime resultDateTime;
        if(num > 0){
            resultDateTime = localDateTime.now().plus(num, unit);
        } else {
            resultDateTime = localDateTime.now().minus(Math.abs(num),unit);
        }
        return resultDateTime;
    }
    /**
   * 时分秒加减
   * @param num 数量
   * @param unit 单位
   * @param localTime 原日期
   * @return LocalDateTime 增加后的日期
   */
    @SuppressWarnings("static-access")
      public static LocalTime addLocalTime(long num,ChronoUnit unit,LocalTime localTime){
        LocalTime resultTime;
        if(num > 0){
            resultTime = localTime.now().plus(num, unit);
        } else {
            resultTime = localTime.now().minus(Math.abs(num), unit);
        }
        return resultTime;
    }
    public static void main(String[] args){
        LocalDateTime time = LocalDateTime.now();
        String rr = formatter(time, "yyyy-MM-dd HH:mm:ss");
        System.out.println(rr);
        LocalDateTime time2 = addLocalDateTime(-2, ChronoUnit.HOURS, time);
        String yy = formatter(time2, "yyyy-MM-dd HH:mm:ss");
        System.out.println(yy);
    }

代码涉及时间日期类的使用等内容，具有简单注释，大家可自行参考。

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原文链接：http://www.cnblogs.com/ywqbj/p/5645910.html