javaarraystype-conversionbytebufferbufferunderflowexception

How to convert a byte array to two long values?

I'm reading a 16 byte array (byte[16]) from a JDBC ResultSet with rs.getBytes("id") and now I need to convert it to two long values. How can I do that?

This is the code I have tried, but I probably didn't use ByteBuffer correctly.

byte[] bytes = rs.getBytes("id");
System.out.println("bytes: "+bytes.length); // prints "bytes: 16"

ByteBuffer buffer = ByteBuffer.allocate(16);
buffer = buffer.put(bytes);

// throws an java.nio.BufferUnderflowException
long leastSignificant = buffer.getLong();
long mostSignificant = buffer.getLong();

I stored the byte array to the database using:

byte[] bytes = ByteBuffer.allocate(16)
    .putLong(leastSignificant)
    .putLong(mostSignificant).array();
Solution

  • You can do

    ByteBuffer buffer = ByteBuffer.wrap(bytes);
long leastSignificant = buffer.getLong(); 
long mostSignificant = buffer.getLong();