Lucene.net Textfield未被索引

Question

使用.NET 6.0和Nuget的Lucene.net-4.8.0-Beta00016，

我正在实施 QuickStart示例来自网站。在文档中使用TextField时，该字段未索引。稍后在BuildIndex方法中搜索未检索任何结果。如果TextField更改为StringField，则该示例有效，搜索将返回有效的结果。

为什么StringField工作和Textfield不工作？我读到Stringfield尚未分析，但是Textfield是，所以也许与Standardanalyzer有关？

public class LuceneFullTextSearchService {

private readonly IndexWriter _writer;
private readonly Analyzer _standardAnalyzer;

public LuceneFullTextSearchService(string indexName)
{
    // Compatibility version
    const LuceneVersion luceneVersion = LuceneVersion.LUCENE_48;
    string indexPath = Path.Combine(Environment.CurrentDirectory, indexName);
    Directory indexDir = FSDirectory.Open(indexPath);

    // Create an analyzer to process the text 
    _standardAnalyzer = new StandardAnalyzer(luceneVersion);

    // Create an index writer
    IndexWriterConfig indexConfig = new IndexWriterConfig(luceneVersion, _standardAnalyzer)
    {
        OpenMode = OpenMode.CREATE_OR_APPEND,
    };
    _writer = new IndexWriter(indexDir, indexConfig);
}

public void BuildIndex(string searchPath)
{
    Document doc = new Document();
    
    TextField docText = new TextField("title", "Apache", Field.Store.YES); 
    doc.Add(docText);
    
    _writer.AddDocument(doc);

    //Flush and commit the index data to the directory
    _writer.Commit();
    
    // Parse the user's query text
    Query query = new TermQuery(new Term("title", "Apache"));
    
    // Search
    using DirectoryReader reader = _writer.GetReader(applyAllDeletes: true);
    IndexSearcher searcher = new IndexSearcher(reader);
    TopDocs topDocs = searcher.Search(query, n: 2);

    // Show results
    Document resultDoc = searcher.Doc(topDocs.ScoreDocs[0].Doc);
    string title = resultDoc.Get("title");
}
}

Answer 1

StandardAnalyzer 包括

但是，当您构建查询时，您使用的文本是“ Apache”而不是“ Apache”，因此不会产生任何命中。

// Parse the user's query text
Query query = new TermQuery(new Term("title", "Apache"));

选项1

较低的搜索词。

// Parse the user's query text
Query query = new TermQuery(new Term("title", "Apache".ToLowerInvariant()));

选项2

使用a 使用相同分析仪，您可以用来构建索引。

QueryParser parser = new QueryParser(luceneVersion, "title", _standardAnalyzer);
Query query = parser.Parse("Apache");

The Lucene.Net.QueryParser package contains several实现（上面的示例使用 lucene.net.queryparsers.classic.queryparser ）。