I'm very new to lucene.net. I wrote this simple console app in C# which indexes some fake data. I then wanted to be able to search the index for various terms using a booleanquery.
I never get any results back. Here is the code. Any help would be greatly appreciated. Thanks.
static void Main(string[] args)
{
StandardAnalyzer analyzer = new StandardAnalyzer();
IndexWriter writer = new IndexWriter("Test", analyzer, true);
Console.WriteLine("Creating index");
for (int i = 0; i < 1500; i++)
{
Lucene.Net.Documents.Document doc = new Lucene.Net.Documents.Document();
doc.Add(new Lucene.Net.Documents.Field("A", i.ToString(), Lucene.Net.Documents.Field.Store.YES, Lucene.Net.Documents.Field.Index.NO));
doc.Add(new Lucene.Net.Documents.Field("B", "LALA" + i.ToString(), Lucene.Net.Documents.Field.Store.YES, Lucene.Net.Documents.Field.Index.NO));
doc.Add(new Lucene.Net.Documents.Field("C", "DODO" + i.ToString(), Lucene.Net.Documents.Field.Store.YES, Lucene.Net.Documents.Field.Index.NO));
doc.Add(new Lucene.Net.Documents.Field("D", i.ToString() + " MMMMM", Lucene.Net.Documents.Field.Store.YES, Lucene.Net.Documents.Field.Index.NO));
writer.AddDocument(doc);
}
writer.Optimize();
writer.Close();
BooleanQuery query = new BooleanQuery();
query.Add(new WildcardQuery(new Term("B", "lala*")), Lucene.Net.Search.BooleanClause.Occur.MUST);
query.Add(new WildcardQuery(new Term("C", "DoDo1*")), Lucene.Net.Search.BooleanClause.Occur.MUST);
IndexSearcher searcher = new IndexSearcher("Test");
Hits hits = searcher.Search(query);
if (hits.Length() > 0)
{
for (int i = 0; i < hits.Length(); i++)
{
Console.WriteLine("{0} - {1} - {2} - {3}",
hits.Doc(i).GetField("A").StringValue(),
hits.Doc(i).GetField("B").StringValue(),
hits.Doc(i).GetField("C").StringValue(),
hits.Doc(i).GetField("D").StringValue());
}
}
searcher.Close();
Console.WriteLine("Done");
Console.ReadLine();
}
I then got it to work by using MultiFieldQueryParser Like so:
static void Main(string[] args)
{
StandardAnalyzer analyzer = new StandardAnalyzer();
IndexWriter writer = new IndexWriter("Test", analyzer, true);
Console.WriteLine("Creating index");
for (int i = 0; i < 1500; i++)
{
Lucene.Net.Documents.Document doc = new Lucene.Net.Documents.Document();
doc.Add(new Lucene.Net.Documents.Field("A", i.ToString(), Lucene.Net.Documents.Field.Store.YES, Lucene.Net.Documents.Field.Index.TOKENIZED));
doc.Add(new Lucene.Net.Documen开发者_如何学JAVAts.Field("B", "LALA" + i.ToString(), Lucene.Net.Documents.Field.Store.YES, Lucene.Net.Documents.Field.Index.TOKENIZED));
doc.Add(new Lucene.Net.Documents.Field("C", "DODO" + i.ToString(), Lucene.Net.Documents.Field.Store.YES, Lucene.Net.Documents.Field.Index.TOKENIZED));
doc.Add(new Lucene.Net.Documents.Field("D", i.ToString() + " MMMMM", Lucene.Net.Documents.Field.Store.YES, Lucene.Net.Documents.Field.Index.TOKENIZED));
writer.AddDocument(doc);
}
writer.Optimize();
writer.Close();
BooleanQuery.SetMaxClauseCount(5000);
Query query = MultiFieldQueryParser.Parse(new string[] { "LALA*", "DODO*" }, new string[] { "B", "C" }, analyzer);
IndexSearcher searcher = new IndexSearcher("Test");
Hits hits = searcher.Search(query);
if (hits.Length() > 0)
{
for (int i = 0; i < hits.Length(); i++)
{
Console.WriteLine("{0} - {1} - {2} - {3}",
hits.Doc(i).GetField("A").StringValue(),
hits.Doc(i).GetField("B").StringValue(),
hits.Doc(i).GetField("C").StringValue(),
hits.Doc(i).GetField("D").StringValue());
}
}
searcher.Close();
Console.WriteLine("Done");
Console.ReadLine();
}
This is possibly the best article I've found for any new lucene developers: http://www.ifdefined.com/blog/post/2009/02/Full-Text-Search-in-ASPNET-using-LuceneNET.aspx
I think there is a problem when building your index. You add four fields to each document, all of them are stored but none of them is indexed (=> Lucene.Net.Documents.Field.Index.NO). You should index at least on field.
Beware that the StandardAnalyzer tokenize each field index in the following way: lowercasing and splitting with common english stop words. So when building your query, use LOWERCASE prefix in order to have hits:
query.Add(new PrefixQuery(new Term("B", "lala")), BooleanClause.Occur.MUST);
query.Add(new PrefixQuery(new Term("C", "dodo")), BooleanClause.Occur.MUST);
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