java – 考虑到夏令时,将本地时间转换为UTC时间,反之亦然

>是的.
>你不需要转换,你只需要分配正确的TimeZone.
>你需要一篇文章？好的,我正在做这件事,但现在让我在这里给出答案.

第一件事先.您的程序应该在UTC TimeZone内部存储Date(或Calendar).那么事实上在GMT,因为Java没有闰秒,但这是另一个故事.
当你需要“转换”的唯一的地方是当你要给用户显示时间.这也是发送电子邮件.在这两种情况下,您需要格式化日期以获取其文本表示.为此,您将使用DateFormat并分配正确的TimeZone：

// that's for desktop application
    // for web application one needs to detect Locale
    Locale locale = Locale.getDefault();
    // again,this one works for desktop application
    // for web application it is more complicated
    TimeZone currentTimeZone = TimeZone.getDefault();
    // in fact I Could skip this line and get just DateTime instance,// but I wanted to show how to do that correctly for
    // any time zone and locale
    DateFormat formatter = DateFormat.getDateTimeInstance(
            DateFormat.DEFAULT,DateFormat.DEFAULT,locale);
    formatter.setTimeZone(currentTimeZone);

    // Dates "conversion"
    Date currentDate = new Date();
    long sixMonths = 180L * 24 * 3600 * 1000;
    Date inSixMonths = new Date(currentDate.getTime() + sixMonths);

    System.out.println(formatter.format(currentDate));
    System.out.println(formatter.format(inSixMonths));
    // for me it prints
    // 2011-05-14 16:11:29
    // 2011-11-10 15:11:29

    // Now for "UTC"
    formatter.setTimeZone(TimeZone.getTimeZone("UTC"));
    System.out.println(formatter.format(currentDate));
    System.out.println(formatter.format(inSixMonths));
    // 2011-05-14 14:13:50
    // 2011-11-10 14:13:50

可以看到,Java关心处理DST.您当然可以手动处理,只需阅读TimeZone related JavaDoc.