Cassandra 2.0.4
I’m using blobs to save and retrieve images in cassanda. However the blob I
get back is not the blob I saved !
I’m saving to CQL like this:
byte[] b= {(byte)10,(byte)20,(byte)30};
int length=b.length;
ByteBuffer buffer =ByteBuffer.wrap(b);
Session session = cluster.connect("keyspace2");
PreparedStatement ps = session.prepare("insert into tweets ( image, user,
interaction_time,imagelength) values(?,?,?,?)");
BoundStatement boundStatement = new BoundStatement(ps);
session.execute( boundStatement.bind( buffer, "majed",
convertor.getTimeUUID(),length));
and retrieving like this:
Session session = cluster.connect("keyspace2");
PreparedStatement ps = session.prepare("select image,user,imagelength from
tweets where user =?");
BoundStatement boundStatement = new BoundStatement(ps);
ResultSet rs =session.execute(boundStatement.bind( "majed"));
ByteBuffer bImage=null;
for (Row row : rs) {
bImage = row.getBytes("image") ;
System.out.println ("Image ");
for (int i=0; i< 40;i++){
System.out.print(String.format("%x ",bImage.get(i)));
if ((i+1)%16 ==0) System.out.println();
}
System.out.println();
}
session.close();
So, I should be saving byte array of 3 long, and the buffer in the save
section is correct. However when I run the retrieve section I’m getting back
the following:
82 0 0 8 0 0 0 28 0 0 0 2 0 0 0 5
0 0 0 3 0 0 0 1 0 0 0 3 a 14 1e
You can see the saved bytes are the last three and there is extra padding at
the front.
Worse if I change the Select statement to:
PreparedStatement ps = session.prepare("select user,image,imagelength from
tweets where user =?”);
I get back:
82 0 0 8 0 0 0 28 0 0 0 2 0 0 0 5
0 0 0 3 0 0 0 1 0 0 0 5 6d 61 6a 65
64 0 0 0 3 a 14 1e
If you look you can see the username “majed” in the returned blob (6d 61 6a 65
64).
any ideas whats going on here ?
Many thanks
Andy
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