java - 为文档添加权重 Lucene 8

Question

我目前正在使用 Lucene 8 开发一个小型大学搜索引擎。我之前已经构建过它，但没有对文档应用任何权重。

我现在需要添加文档的 PageRank 作为每个文档的权重，并且我已经计算了 PageRank 值。如何在 Lucene 8 中向 Document 对象(不是查询词)添加权重？我在网上查了很多解决方案，但它们只适用于旧版本的Lucene。 Example source

这是我的(更新)代码，它从 File 对象生成 Document 对象:

public static Document getDocument(File f) throws FileNotFoundException, IOException {
    Document d = new Document();

    //adding a field
    FieldType contentType = new FieldType();
    contentType.setStored(true);
    contentType.setTokenized(true);
    contentType.setIndexOptions(IndexOptions.DOCS_AND_FREQS_AND_POSITIONS_AND_OFFSETS);
    contentType.setStoreTermVectors(true);

    String fileContents = String.join(" ", Files.readAllLines(f.toPath(), StandardCharsets.UTF_8));
    d.add(new Field("content", fileContents, contentType));

    //adding other fields, then...

    //the boost coefficient (updated):
    double coef = 1.0 + ranks.get(path);
    d.add(new DoubleDocValuesField("boost", coef));

    return d;

}

我当前方法的问题是我需要一个 CustomScoreQuery 对象来搜索文档，但这在 Lucene 8 中不可用。另外，我现在不想降级到 Lucene 7毕竟是我在Lucene 8中编写的代码。

<小时/>

编辑:

经过一些(冗长的)研究，我向每个持有提升的文档添加了一个 DoubleDocValuesField (请参阅上面更新的代码)，并按照建议使用 FunctionScoreQuery 进行搜索@埃里克拉沃。但是，现在我的所有文档的分数都与它们的提升完全一致，无论查询如何!我该如何解决这个问题？这是我的搜索功能:

public static TopDocs search(String query, IndexSearcher searcher, String outputFile) {
    try {
        Query q_temp = buildQuery(query); //the original query, was working fine alone

        Query q = new FunctionScoreQuery(q_temp, DoubleValuesSource.fromDoubleField("boost")); //the new query
        q = q.rewrite(DirectoryReader.open(bm25IndexDir));
        TopDocs results = searcher.search(q, 10);

        ScoreDoc[] filterScoreDosArray = results.scoreDocs;
        for (int i = 0; i < filterScoreDosArray.length; ++i) {
            int docId = filterScoreDosArray[i].doc;
            Document d = searcher.doc(docId);

            //here, when printing, I see that the document's score is the same as its "boost" value. WHY??
            System.out.println((i + 1) + ". " + d.get("path")+" Score: "+ filterScoreDosArray[i].score);
        }

        return results;
    }
    catch(Exception e) {
        e.printStackTrace();
        return null;
    }
}

//function that builds the query, working fine
public static Query buildQuery(String query) {
    try {
        PhraseQuery.Builder builder = new PhraseQuery.Builder();
        TokenStream tokenStream = new EnglishAnalyzer().tokenStream("content", query);
        tokenStream.reset();

        while (tokenStream.incrementToken()) {
          CharTermAttribute charTermAttribute = tokenStream.getAttribute(CharTermAttribute.class);
          builder.add(new Term("content", charTermAttribute.toString()));
        }

        tokenStream.end(); tokenStream.close();
        builder.setSlop(1000);
        PhraseQuery q = builder.build();

        return q;
    }
    catch(Exception e) {
        e.printStackTrace();
        return null;
    }
}

Answer 1

从Lucene 6.5.0开始:

Index-time boosts are deprecated. As a replacement, index-time scoring factors should be indexed into a doc value field and combined at query time using eg. FunctionScoreQuery. (Adrien Grand)

建议不要使用索引时间提升，而是将评分因素(即长度标准化因素)编码到文档值字段中。 (参见LUCENE-6819)