java8中的LocalDate，LocalTime，LocalDateTime與Date的轉換和使用

dream21st發表於2018-06-12
JavaLDA
package com.wangwenjun.java8;


import java.time.Duration;
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.ZonedDateTime;
import java.time.format.DateTimeFormatter;
import java.util.Date;


public class LocalDateUtil {


private final static String FORMAT_PATTERN1="yyyy-MM-dd HH:mm:ss";
private final static String FORMAT_PATTERN2="yyyyMMddHHmmss";
private final static String FORMAT_PATTERN3="yyyy-MM-dd";
private final static String FORMAT_PATTERN4="yyyyMMdd";

public static void main(String[] args) {
Date date1=new Date();
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
System.out.println(localDateFormat(LocalDate.now(),FORMAT_PATTERN3));
System.out.println(localDateTimeFormat(LocalDateTime.now(),FORMAT_PATTERN1));
System.out.println(localDateTimeFormat(LocalDateTime.now(),FORMAT_PATTERN2));
System.out.println(localDateTimeToDate(LocalDateTime.now()));
System.out.println(dateFormat(new Date(),FORMAT_PATTERN4));
System.out.println(minusToMillsLocalDateTime(LocalDateTime.now(),LocalDateTime.now().minusSeconds(1)));
System.out.println(minusToMillsDate(date1,new Date()));
System.out.println(localDateParse("2018-06-12",FORMAT_PATTERN3));
System.out.println(localDateTimeParse("2018-06-12 16:04:43",FORMAT_PATTERN1));
Period p=periodDate(date1,new Date());
System.out.println("year:"+p.getYears()+"month:"+p.getMonths()+"day:"+p.getDays());
System.out.println("----------------------------------------------------------------");
Date date2=localDateToDate(LocalDate.now().minusMonths(1).minusDays(2));
Date date3=localDateToDate(LocalDate.now());
Period p2=periodDate(date2,date3);
System.out.println("year:"+p2.getYears()+"month:"+p2.getMonths()+"day:"+p2.getDays());
System.out.println("----------------------------------------------------------------");
Period p1=periodLocalDate(LocalDate.now().minusDays(2),LocalDate.now());
System.out.println("year:"+p1.getYears()+"month:"+p1.getMonths()+"day:"+p1.getDays());
}

/**
* 將localDate 按照一定的格式轉換成String
* @param localDate
* @param pattern
* @return
*/
public static String localDateFormat(LocalDate localDate,String pattern){
return localDate.format(DateTimeFormatter.ofPattern(pattern));
}

/**
* 將localDateTime 按照一定的格式轉換成String
* @param localDateTime
* @param pattern
* @return
*/
public static String localDateTimeFormat(LocalDateTime localDateTime,String pattern){
return localDateTime.format(DateTimeFormatter.ofPattern(pattern));
}

/**
* 將String 按照pattern 轉換成LocalDate
* @param time
* @param pattern
* @return
*/
public static LocalDate localDateParse(String time,String pattern){
return LocalDate.parse(time,DateTimeFormatter.ofPattern(pattern));
}

/**
* 將String 按照pattern 轉換成LocalDateTime
* @param time
* @param pattern
* @return
*/
public static LocalDateTime localDateTimeParse(String time,String pattern){
return LocalDateTime.parse(time,DateTimeFormatter.ofPattern(pattern));
}

/**
* 將date轉換成String
* @param date
* @param pattern
* @return
*/
public static String dateFormat(Date date,String pattern){
return localDateTimeFormat(dateToLocalDateTime(date),pattern);
}

/**
* 將LocalDate 轉換成 Date
* @param localDate
* @return
*/
public static Date localDateToDate(LocalDate localDate){
ZoneId zoneId = ZoneId.systemDefault();
        ZonedDateTime zdt = localDate.atStartOfDay(zoneId);
return Date.from(zdt.toInstant());
}

/**
* 將LocalDateTime 轉換成 Date
* @param localDateTime
* @return
*/
public static Date localDateTimeToDate(LocalDateTime localDateTime){
ZoneId zoneId = ZoneId.systemDefault();
        ZonedDateTime zdt = localDateTime.atZone(zoneId);
return Date.from(zdt.toInstant());
}

/**
* 將 Date 轉換成LocalDate
* atZone()方法返回在指定時區從此Instant生成的ZonedDateTime。
* @param date
* @return
*/
public static LocalDate dateToLocalDate(Date date){
Instant instant = date.toInstant();
        ZoneId zoneId = ZoneId.systemDefault();
return instant.atZone(zoneId).toLocalDate();
}

/**
* 將 Date 轉換成LocalDateTime
* atZone()方法返回在指定時區從此Instant生成的ZonedDateTime。
* @param date
* @return
*/
public static LocalDateTime dateToLocalDateTime(Date date){
Instant instant = date.toInstant();
        ZoneId zoneId = ZoneId.systemDefault();
return instant.atZone(zoneId).toLocalDateTime();
}

/**
* 計算兩個LocalDateTime 之間的毫秒數
* @param time1
* @param time2
* @return
*/
public static Long minusToMillsLocalDateTime(LocalDateTime time1,LocalDateTime time2){
return Duration.between(time1, time2).toMillis();
}

/**
* 計算兩個LocalTime 之間的毫秒數
* @param time1
* @param time2
* @return
*/
public static Long minusToMillsLocalTime(LocalTime time1,LocalTime time2){
return Duration.between(time1, time2).toMillis();
}

/**
* 計算兩個LocalDate 之間的毫秒數
* @param time1
* @param time2
* @return
*/
public static Long minusToMillsLocalDate(LocalDate time1,LocalDate time2){
return Duration.between(time1, time2).toMillis();
}
/**
* 計算兩個LocalDate 之間的Period
* @param time1
* @param time2
* @return
*/
public static Period periodLocalDate(LocalDate time1,LocalDate time2){
return Period.between(time1,time2);
}
/**
* 計算兩個Date 之間的Period
* @param date1
* @param date2
* @return
*/
public static Period periodDate(Date date1,Date date2){
return periodLocalDate(dateToLocalDate(date1),dateToLocalDate(date2));
}
/**
* 計算兩個Date之間的 Period
* @param time1
* @param time2
* @return
*/
public static Long minusToMillsDate(Date time1,Date time2){
return minusToMillsLocalDateTime(dateToLocalDateTime(time1),dateToLocalDateTime(time2));
}
}

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