java - 如何使用 Java 将字符串日期和字符串时间组合成单个即时日期时间？

Question

这个问题已经有答案了:

How to combine date and time into a single object? (3 个回答)

已关闭 3 年前。

我想将字符串日期(“19801115”)和字符串时间(“1530”)组合成一个即时日期时间。

例如:有两个字符串变量:

String applicationDate = "19801115";
String applicationTime = "1530";

并将它们组合成applicationDateTime (即时类型，例如:“1980-11-15T15:30:00Z”)。我该如何实现这一目标？谢谢。

Answer 1

String dateString = "19801115";
String timeString = "1530";

Date date = null;
try {
    date = new SimpleDateFormat("yyyyMMddhhmm").parse(dateString + timeString);
} catch (ParseException e) {
    e.printStackTrace();
}
Instant reqInstant = date.toInstant();
System.out.println(reqInstant); // time here depends on your local settings, may differ from 15:30

// this way you adjust an Instant to a time zone you need
ZonedDateTime zdt = ZonedDateTime.ofInstant(reqInstant, ZoneId.systemDefault() /*<- needed time zone here*/);
System.out.println(zdt.toInstant()/*returns an Instant*/);

此外，与 DateTimeFormatter 具有类似的功能:

    String dateString = "19801115";
    String timeString = "1530";

    DateTimeFormatter dtf = new DateTimeFormatterBuilder()
            .appendPattern("yyyyMMddHHmm")
            .toFormatter()
            .withZone(ZoneId.systemDefault() /*<- needed time zone here*/);
    ZonedDateTime zdtOriginal = ZonedDateTime.parse(dateString + timeString, dtf);

    System.out.println(zdtOriginal.toInstant()/*returns an Instant*/);

    // this way you adjust an Instant to a time zone you need
    ZonedDateTime zdt = zdtOriginal.withZoneSameLocal(ZoneId.of("GMT") /*<- needed time zone here*/);
    System.out.println(zdt.toInstant()/*returns an Instant*/);