Java LocalDateTime用法详解,日期时间处理不再难_Java

1. 简介

localdatetime、localdate、localtime 是java8全新的日期框架，较之前的util.date以及calander使用起来更加的方便直观，下面介绍几种常见的日期对象用法。

localdatetime：日期加时间的日期对象，包含年月日时分秒
localdate：日期类，包含年月日
localtime：时间类，包含时分秒

localdate、localtime、localdatetime、instant均为不可变对象，修改这些对象对象会返回一个副本。而并非在原对象上修改。

2. localdatetime用法

2.1 获取当前的时间

localdatetime now = localdatetime.now();

2.2 根据年月日格式化时间

localdatetime localdatetime = localdatetime.of(2021, 6, 16, 16, 37, 20, 814 * 1000 * 1000);
localdatetime ldt = localdatetime.now().withyear(2021).withmonth(6).withdayofmonth(16).withhour(10).withminute(10).withsecond(59).withnano(999 * 1000 * 1000);

注意：最后一个参数是纳秒

2.3 获取时区东八区的时间

localdatetime datetime = localdatetime.now(zoneid.of("asia/shanghai"));
localdatetime datetime2 = localdatetime.now(zoneid.of("+8"));

2.4 从localdatetime中获取年月日等时间信息

localdatetime now = localdatetime.now();
int year = now.getyear();
int month = now.getmonthvalue();
int dayofyear = now.getdayofyear();
int dayofmonth = now.getdayofmonth();

int hour = now.gethour();
int minute = now.getminute();
int second = now.getsecond();
int nano = now.getnano();

system.out.println(year + " " + month + " " + dayofyear + " " + dayofmonth);
system.out.println(hour + " " + minute + " " + second + " " + nano);

2.5 从localdatetime中获取localdate与localtime

localdate localdate = now.tolocaldate();
localtime localtime = now.tolocaltime();

2.6 日期计算

localdatetime now = localdatetime.now();
localdatetime tomorrow = now.plusdays(1l);
tomorrow = tomorrow.plushours(2l);
tomorrow = tomorrow.plusminutes(10l);

localdatetime yesterday = now.minus(duration.ofdays(1));
yesterday = yesterday.plushours(2l);
yesterday = yesterday.plusminutes(10l);

system.out.println(tomorrow);
system.out.println(yesterday);

注意：localdatetime、localdate、localtime 日期对象每次修改都会创建一个新的对象，而非在原有对象基础上修改

2.7 获取某天的整点时间，通过with修改值

localdatetime now = localdatetime.now();
localdatetime ldt1 = now.withhour(10).withminute(0).withsecond(0).withnano(0);

2.8 获取毫秒值

instant instant = instant.now();
long min = instant.toepochmilli();
system.out.println(min);

2.9 计算两个时间的时间差

下面这种方式可以获取两个时间点相差n年n月n日n时n分n秒

localdatetime fromdatetime = localdatetime.of(1992, 6, 11, 10, 23, 55);
localdatetime todatetime = localdatetime.now();
localdatetime tempdatetime = localdatetime.from(fromdatetime);

long years = tempdatetime.until(todatetime, chronounit.years);
tempdatetime = tempdatetime.plusyears(years);

long months = tempdatetime.until(todatetime, chronounit.months);
tempdatetime = tempdatetime.plusmonths(months);

long days = tempdatetime.until(todatetime, chronounit.days);
tempdatetime = tempdatetime.plusdays(days);

long hours = tempdatetime.until(todatetime, chronounit.hours);
tempdatetime = tempdatetime.plushours(hours);

long minutes = tempdatetime.until(todatetime, chronounit.minutes);
tempdatetime = tempdatetime.plusminutes(minutes);

long seconds = tempdatetime.until(todatetime, chronounit.seconds);

system.out.println("" + java.time.duration.between(tempdatetime, todatetime).tohours());
system.out.println(years + " years "
        + months + " months "
        + days + " days "
        + hours + " hours "
        + minutes + " minutes "
        + seconds + " seconds.");

如果只想获取两个时间相差的天数或者小时数，可以使用以下方法

localdatetime ldt1 = localdatetime.of(1992, 6, 11, 10, 23, 55);
localdatetime ldt2 = localdatetime.now();
system.out.println(duration.between(ldt1, ldt2).todays());
system.out.println(duration.between(ldt1, ldt2).tohours());

3. localdatetime与date、string互转

3.1 localdatetime 转 date

public static date localdatetime2date(localdatetime localdatetime) {
    return date.from(localdatetime.atzone(zoneid.systemdefault()).toinstant());
}

3.2 localdatetime 转 string

private static final datetimeformatter date_time_formatter = datetimeformatter.ofpattern("yyyy-mm-dd hh:mm:ss");
public static string localdatetime2string(localdatetime localdatetime) {
    return localdatetime.format(date_time_formatter);
}

注意：datetimeformatter是线程安全的类，可以将此类放到常量中。

3.3 string 转 localdatetime

private static final datetimeformatter date_time_formatter = datetimeformatter.ofpattern("yyyy-mm-dd hh:mm:ss");
public static localdatetime string2localdatetime(string str) {
    return localdatetime.parse(str, date_time_formatter);
}

3.4 string 转 date

public static date string2date(string str) throws parseexception {
    simpledateformat simpledateformat = new simpledateformat("yyyy-mm-dd hh:mm:ss");
    return simpledateformat.parse(str);
}

注意：simpledateformat是非线程安全的类，在多线程操作时会报错，所以此对象每次用的时候最好新建。或者作为方法入参传递进来。

3.5 date 转 localdatetime

public static localdatetime date2localdatetime(date date) {
    return date.toinstant()
            .atzone(zoneid.systemdefault())
            .tolocaldatetime();
}

3.6 date 转 string

public static string date2string(date date) {
    simpledateformat formatter = new simpledateformat("yyyy-mm-dd hh:mm:ss");
    return formatter.format(date);
}

总结

以上为个人经验，希望能给大家一个参考，也希望大家多多支持代码网。

Java LocalDateTime用法详解,日期时间处理不再难

2026年10月09日 • Java •我要评论