SimpleDateFormat getHors()返回不正确的值

2022-08-24 00:00:00 android simpledateformat java

为什么"09:50"的getHour()返回8? 代码:

SimpleDateFormat sdf = new SimpleDateFormat("HH:mm");
Date date = sdf.parse("09:50");
int hours = date.getHours(); // return 8 instead of 9 ???

解决方案

您的SimpleDateFormat可能尚未设置为默认时区。 呼叫:

sdf.setTimeZone(TimeZone.getDefault());

在解析文字之前,应该可以解决您的问题。 我测试了以下代码:

...
    public static final SimpleDateFormat CDfTimestamp = new SimpleDateFormat(
            "yyyy-MM-dd HH:mm:ss");
...
    Date da1 = null;
    for (String dl1 : new String[] { "1970-01-01 12:34:56",
            "2016-01-01 12:34:56" }) {
        try {
            CDfTimestamp.setTimeZone(TimeZone.getTimeZone("GMT+05:00"));
            da1 = CDfTimestamp.parse(dl1);
            System.out.printf("parse GMT+05:00 %s -> %d %d %d (os=%d)
", dl1, da1
                    .getHours(), da1.getMinutes(), da1.getSeconds(), CDfTimestamp
                    .getTimeZone().getOffset(0));
            CDfTimestamp.setTimeZone(TimeZone.getTimeZone("UTC"));
            da1 = CDfTimestamp.parse(dl1);
            System.out.printf("parse UTC       %s -> %d %d %d (os=%d)
", dl1, da1
                    .getHours(), da1.getMinutes(), da1.getSeconds(), CDfTimestamp
                    .getTimeZone().getOffset(0));
            CDfTimestamp.setTimeZone(TimeZone.getDefault());
            da1 = CDfTimestamp.parse(dl1);
            System.out.printf("parse default   %s -> %d %d %d (os=%d)
", dl1, da1
                    .getHours(), da1.getMinutes(), da1.getSeconds(), CDfTimestamp
                    .getTimeZone().getOffset(0));
        } catch (ParseException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
...

获取以下输出:

parse GMT+05:00 1970-01-01 12:34:56 -> 8 34 56 (os=18000000)
parse UTC       1970-01-01 12:34:56 -> 13 34 56 (os=0)
parse default   1970-01-01 12:34:56 -> 12 34 56 (os=3600000)
parse GMT+05:00 2016-01-01 12:34:56 -> 8 34 56 (os=18000000)
parse UTC       2016-01-01 12:34:56 -> 13 34 56 (os=0)
parse default   2016-01-01 12:34:56 -> 12 34 56 (os=3600000)

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