来自Date的LocalTime [英] LocalTime from Date

问题描述

我正在尝试将 Date 实例转换为 LocalTime 实例。

I'm trying to convert a Date instance to a LocalTime instance.

// Create the Date
Date date = format.parse("2011-02-18 05:00:00.0");    

// Convert to Calendar
Calendar cal = Calendar.getInstance();
cal.setTime(date);

// Convert Calendar to LocalTime
Instant instant = Instant.ofEpochMilli(cal.getTimeInMillis());
LocalTime convert = LocalDateTime.ofInstant(instant, ZoneId.systemDefault()).toLocalTime();

我没有收到编译器错误，但 LocalTime 实例值错误。

I don't get a compiler error but the LocalTime instance values are wrong.

我认为它不起作用，因为日期将时间存储在 fasttime 而不是 cdate 。

I think it does not work because Date stores time in fasttime instead of cdate.

我正在使用JDK 1.8版。

I'm using JDK version 1.8.

推荐答案

您的输入实际上是 LocalDateTime 。简单地将其解析为 LocalDateTime 然后从中获取 LocalTime 会简单得多。没有时区可以担心，没有一些遗留类别（尽可能避免日期和日历）

Your input is effectively a LocalDateTime. It would be much simpler to simply parse that to a LocalDateTime and then get the LocalTime from that. No time zones to worry about, no somewhat-legacy classes (avoid Date and Calendar where possible...)

import java.time.*;
import java.time.format.*;
import java.util.*;

public class Test {

    public static void main(String[] args) {
        DateTimeFormatter formatter =
            DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss.S", Locale.US);

        String text = "2011-02-18 05:00:00.0";
        LocalDateTime localDateTime = LocalDateTime.parse(text, formatter);
        LocalTime localTime = localDateTime.toLocalTime();
        System.out.println(localTime);
    }
}

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