SpanFirstQuery not working in lucene

问题

I'm trying to use SpanFirstQuery to match beginning of a field in lucene. But it just doesn't seem to work. here's code i'm using.

Map<String, Analyzer> searchAnalyzers = new HashMap<String, Analyzer>();
searchAnalyzers.put(NAME, new KeywordAnalyzer());
searchAnalyzers.put(ORGANIZATION_NAME, new KeywordAnalyzer());
searchAnalyzers.put(ORGANIZATION_POSITION, new KeywordAnalyzer());
PerFieldAnalyzerWrapper perFieldAnalyzerWrapper = new PerFieldAnalyzerWrapper(new KeywordAnalyzer(), searchAnalyzers);
MultiFieldQueryParser multiFieldQueryParser = new MultiFieldQueryParser(Version.LUCENE_40, mSearchFields, perFieldAnalyzerWrapper); //mSearchFiels is array of fiels
multiFieldQueryParser.setDefaultOperator(QueryParser.Operator.AND);
Query query = (Utils.isEmpty(queryString)) ? new MatchAllDocsQuery() : multiFieldQueryParser.parse(QueryParser.escape(queryString)); //queryString is text to be searched

Term term = new Term(NAME, queryString);
SpanFirstQuery spanFirstQuery = new SpanFirstQuery(new SpanTermQuery(term), 5);
spanFirstQuery.setBoost(5.0f);
BooleanQuery booleanQuery = new BooleanQuery();
booleanQuery.add(spanFirstQuery, BooleanClause.Occur.SHOULD);
booleanQuery.add(query, BooleanClause.Occur.MUST);
indexSearcher.search(booleanQuery, 100);

it returns results when only single character is passed in queryString. but doesn't work when i pass string. always totalHits count is 0.

来源：https://stackoverflow.com/questions/41447005/spanfirstquery-not-working-in-lucene