import java.time.Instant;import java.time.LocalDateTime;import java.time.ZoneId;import java.time.format.DateTimeFormatter;import java.time.temporal.ChronoUnit;import java.time.temporal.TemporalAccessor;import java.util.Date;public class DateUtil {    /**    *@description(将 date 转换成指定格式的字符串)    *@date 2018/4/27 11:20    *@param date, format    *@return java.lang.String    */    public static String formatDate(Date date,String format){        LocalDateTime localDateTime=LocalDateTime.ofInstant(date.toInstant(),ZoneId.systemDefault());        DateTimeFormatter formatter=DateTimeFormatter.ofPattern(format);        return localDateTime.format(formatter);    }    /**    *@description(间隔天数)    *@date 2018/6/4 17:42     *@param [start, end]    *@return long     */    public static long betweenDays(Date start,Date end){        LocalDateTime nowDateTime= LocalDateTime.ofInstant(start.toInstant(), ZoneId.systemDefault());        LocalDateTime thirdDateTime= LocalDateTime.ofInstant(end.toInstant(), ZoneId.systemDefault());        long between = ChronoUnit.DAYS.between(nowDateTime, thirdDateTime);        return between;    }    /**    *@Description(将带T 的字符串，转成 date类型)    *@Date 2018/4/23    *@Param [str]    *@return java.util.Date     * 请使用 org.apache.commons.lang3.time.FastDateFormat ,更加方便    */    @Deprecated    public static Date parseDate(String str){        TemporalAccessor date = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss").withZone(ZoneId.systemDefault()).parse(str);        return Date.from(Instant.from(date));    }    /*添加时间*/    public static Date addTime(Date date, long num, ChronoUnit timeUnit){        return Date.from(Instant.ofEpochMilli(date.getTime()).plus(num,timeUnit));    }  }

 apache lang3 实现日期转换

import org.apache.commons.lang3.time.FastDateFormat;import java.text.ParseException;import java.util.Date;public class JVMTest {    public static String format(Date date,String format)  {        FastDateFormat pattern=FastDateFormat.getInstance(format);        return pattern.format(date);    }    public static Date parse(String dateStr,String format) throws ParseException {        FastDateFormat pattern=FastDateFormat.getInstance(format);        return pattern.parse(dateStr);    }}