如何将dos日期时间转换为Unix时间？

Question

Unix时间是从1970年开始算起的数字秒。Java文件时间是1970年后的毫秒数。都是格林威治时区。但是dos datetime是位字段格式，几位表示日、月、年和时间hh、mm、ss、本地时区。将Unix时间转换为文件时间很容易- mul。1000。从Dos datetime到Unix的转换很困难。存档库UnAceV2具有Dos datetime格式。如何将其转换为Unix？

Answer 1

查看java.util.zip.ZipEntry.dosToJavaTime(long)和java.util.zip.ZipEntry.javaToDosTime(long)的源代码

Answer 2

    /** Converts DOS time to Java time (number of milliseconds since epoch). */
    private long dosToJavaTime(long dosTime) {
        Calendar cal = Calendar.getInstance();
        cal.set(Calendar.YEAR, (int) ((dosTime >> 25) & 0x7f) + 1980);
        cal.set(Calendar.MONTH, (int) ((dosTime >> 21) & 0x0f) - 1);
        cal.set(Calendar.DATE, (int) (dosTime >> 16) & 0x1f);
        cal.set(Calendar.HOUR_OF_DAY, (int) (dosTime >> 11) & 0x1f);
        cal.set(Calendar.MINUTE, (int) (dosTime >> 5) & 0x3f);
        cal.set(Calendar.SECOND, (int) (dosTime << 1) & 0x3e);
        cal.set(Calendar.MILLISECOND, 0);
        return cal.getTime().getTime();
    }