Changing the index

[Drayfe]

Hi everybody!!!
I'm working with lucene but I have a problem.
In the past I had an index with the field "content" indexed with a sentence similar to this:

doc.add(new Field ("content", new FileReader(f), Field.TermVector.YES));

Now I have to change my index for a bigger one, but now the field "content" is a string. As you can imagine, I use the termvectors to get an array of terms and an array of frequencies for each document. But now, I really don't know how to search in that new field.
Could anybody guide me?

Thanks.