問題描述

我想將 yyyy-MM-dd'T'HH:mm:ss 形式的時間戳解析為 LocalDateTime.這樣做時，如果它們是 00，它會去除秒數.

I want to parse a timestamp in the form of yyyy-MM-dd'T'HH:mm:ss as LocalDateTime. When doing so, it strips the seconds if they are 00.

如此處所述，我需要使用自定義格式化程序

As described here, I need to use a custom formatter

LocalDateTime date = LocalDateTime.parse("2008-10-02T12:30:00");
DateTimeFormatter f = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss");

String dateString = date.toString();
String dateFormatted = date.format(f);

System.out.println(dateString); // 2008-10-02T12:30

這個可行，但它返回一個 String:

This one works, but it returns a String:

System.out.println(dateFormatted); // 2008-10-02T12:30:00

當我將字符串解析為 LocalDateTime 時，它會再次剝離 00:

When I parse the string to LocalDateTime it strips the 00 again:

LocalDateTime dateLDT = LocalDateTime.parse(dateFormatted, f);
System.out.println(dateLDT); // 2008-10-02T12:30

那么如何將日期解析為 LocalDateTime，而不是 String，并在末尾保留 00?

So how can I parse a date as LocalDateTime, instead of String, and keep the 00 at the end?

推薦答案

你應該期待兩者之間的輸出差異

You should expect a difference in output between

LocalDateTime dateLDT = LocalDateTime.parse(dateFormatted, f);
System.out.println(dateLDT);

還有

System.out.println(dateLDT.format(f)) //or f.format(dateLDT)

System.out.println(dateLDT); 打印 dateLDT.toString() 的值，預計不會產生與您的模式相同的輸出.

System.out.println(dateLDT); prints the value of dateLDT.toString(), which is not expected to produce the same output as your pattern.

當您查看 LocalDateTime.toString() 時，您會看到它將時間部分委托給 LocalTime.toString()，它有條件地打印秒數:

When you look at LocalDateTime.toString(), you'll see that it delegates the time part to LocalTime.toString(), which prints seconds conditionally:

public String toString() {
    ...
    if (secondValue > 0 || nanoValue > 0) {
        buf.append(secondValue < 10 ? ":0" : ":").append(secondValue);
        ...
        }
    }
    return buf.toString();
}

如果它的值為0，它只是省略秒字段.

It simply omits the seconds field if its value is 0.

在這種情況下，如果您必須確定輸出/輸入格式，您需要始終使用 DateTimeFormatter 來格式化您的日期.

What you need to do in this case is always use a DateTimeFormatter to format your date if you have to be certain about the output/input format.

這篇關于將時間戳解析為 LocalDateTime的文章就介紹到這了，希望我們推薦的答案對大家有所幫助，也希望大家多多支持html5模板網！