Query vs. BooleanQuery

[Li Bing <lb...@gmail.com>]

Dear all,

I tried to search using two approaches, Query and BooleanQuery. To my
surprise, the two behaves different on the same index? Or I made
something wrong?

On the same index, Query can get results whereas BooleanQuery get NOTHING. Why?

The codes are shown as follows.

Using Query,

        ......
	IndexSearcher searcher = new IndexSearcher(fsDirectory);
	Analyzer chineseAnalyzer = new ChineseAnalyzer();
	QueryParser queryParser = new QueryParser(searchField, chineseAnalyzer);
	Query query = queryParser.Parse(DBTools.FilterKeyFieldValue(searchKeyword));
	Hits results = searcher.Search(query);
        ......

Using BooleanQuery,

        ......
	IndexSearcher searcher = new IndexSearcher(fsDirectory);
	Term term = new Term(searchField, searchKeyword);
	TermQuery termQuery = new TermQuery(term);
	BooleanQuery booleanQuery = new BooleanQuery();
	booleanQuery.Add(termQuery, BooleanClause.Occur.MUST);
	Hits results = searcher.Search(booleanQuery);
        ......

I think the codes should be correct. But why do they get different
results on the same index?

Thanks so much for your help!
LB