Java8为LocalDateTime添加时间不起作用 [英] Java8 Adding Hours To LocalDateTime Not Working

问题描述

我尝试过如下，但在两种情况下它都显示同一时间？我做错了。

I tried like below, but in both the cases it is showing same time? What i am doing wrong.

    LocalDateTime currentTime = LocalDateTime.now(ZoneId.of("UTC"));
    Instant instant = currentTime.toInstant(ZoneOffset.UTC);
    Date currentDate = Date.from(instant);
    System.out.println("Current Date = " + currentDate);
    currentTime.plusHours(12);
    Instant instant2 = currentTime.toInstant(ZoneOffset.UTC);
    Date expiryDate = Date.from(instant2);
    System.out.println("After 12 Hours = " + expiryDate);

当前日期时间与12小时后相同......

"Current Date" Time is showing Same as "After 12 Hours"...

推荐答案

LocalDateTime 的文档指定 LocalDateTime <的实例/ code>是不可变的，例如 plusHours

The documentation of LocalDateTime specifies the instance of LocalDateTime is immutable, for example plusHours

public LocalDateTime plusHours（长时间）

返回指定的 LocalDateTime 的副本已添加
小时数。

Returns a copy of this LocalDateTime with the specified number of hours added.

此实例不可变且不受此方法调用的影响。

This instance is immutable and unaffected by this method call.

参数：

小时 - 要添加的小时数，可能为负数

退货：

a LocalDateTime基于此日期时间添加小时数，而不是null

投掷：

DateTimeException - 如果结果超出支持的日期范围

Parameters:
hours - the hours to add, may be negative
Returns:
a LocalDateTime based on this date-time with the hours added, not null
Throws:
DateTimeException - if the result exceeds the supported date range

那么，你创建一个新的 LocalDateTime实例执行加号操作时，需要按如下方式赋值：

So, you create a new instance of LocalDateTime when you execute plus operation, you need to assign this value as follows:

LocalDateTime nextTime = currentTime.plusHours(12);
Instant instant2 = nextTime.toInstant(ZoneOffset.UTC);
Date expiryDate = Date.from(instant2);
System.out.println("After 12 Hours = " + expiryDate);

我希望它对您有所帮助。

I hope it can be helpful for you.

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