You can search multiple indexes at once using a MultiReader
. Just open readers normally on each of the indexes, and create the MultiReader
, passing those readers into the constructor, like:
IndexReader reader1 = DirectoryReader.open(directory1);
IndexReader reader2 = DirectoryReader.open(directory2);
MultiReader multiReader = new MultiReader(reader1, reader2);
IndexSearcher searcher = new IndexSearcher(multiReader);