How do I convert a Foxpro 8-byte datetime into a Java Date object?
I saw the same question on the site here:
How can i interpret "FoxPro" dbf file date time field (eight-byte) in my c++ program?
but that answer is in C++, and I don't know how to apply it to Java.
I don't have much data for testing, but here is a class that gives me the correct answer based on the example given in the comments to the question you mentioned.
It is worth mentioning that the answer to the C++ question is wrong. The value is not a double. This solution is based on the information given in this question (though not on its answer), which tells us that the date actually consists of two integers.
import java.nio.ByteBuffer;
import java.util.Date;
class FoxProDateConverter {
private static final long BASE_FOXPRO_MILLIS = 210866803200000L;
private static final long DAY_TO_MILLIS_FACTOR = 24L * 60L * 60L * 1000L;
public static Date convert( byte[] foxProDate ) {
if ( foxProDate.length != 8 ) {
throw new IllegalArgumentException("FoxPro date must be 8 bytes long");
}
// FoxPro date is stored with bytes reversed.
byte[] reversedBytes = new byte[8];
for ( int i = 0; i < 8; i++ ) {
reversedBytes[i] = foxProDate[8 - i - 1];
}
// Grab the two integer fields from the byte array
ByteBuffer buf = ByteBuffer.wrap(reversedBytes);
long timeFieldMillis = buf.getInt();
long dateFieldDays = buf.getInt();
// Convert to Java date by converting days to milliseconds and adjusting
// to Java epoch.
return new Date(dateFieldDays * DAY_TO_MILLIS_FACTOR - BASE_FOXPRO_MILLIS + timeFieldMillis);
}
public static void main(String[] args) {
byte[] bytes = {0x0E, 0x61, 0x25, 0x00, (byte)0xF8, (byte) 0xBF, (byte) 0xEA, 0x02};
Date d = FoxProDateConverter.convert(bytes);
System.out.println( d );
}
}
