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小编典典

如何在Hibernate Search / Lucene中禁用默认评分/增强功能？

hibernate

我想为用户提供最相关，最好的结果。例如，我要奖励标题，说明，所附照片等较大的记录。对于上下文：记录是自行车路线，路线点（坐标）和元数据（例如照片，评论等）。

现在，我已经使用索引了这些记录Hibernate，然后使用Lucenein 在索引中搜索Hibernate Search。为了对结果进行评分，我根据文档属性构建查询，并boostedTo()在中使用增强查询should BooleanJunction clause：

bj.should(qb.range().onField("descriptionLength").above(3000).createQuery()).boostedTo(3.0f);   
bj.should(qb.range().onField("views.views").above(5000).createQuery()).boostedTo(3.0f);     
bj.should(qb.range().onField("nameLength").above(20).createQuery()).boostedTo(1.0f);     
bj.should(qb.range().onField("picturesLength").above(0).createQuery()).boostedTo(5.0f);
bj.should(qb.keyword().onField("routePoints.poi.participant").matching("true").createQuery()).boostedTo(10.0f);

为了尝试禁用Lucene的评分，我重写了DefaultSimilarity该类，将所有比较设置为1.0f，并通过Hibernate配置启用了它：

public class IgnoreScoringSimilarity extends DefaultSimilarity {
    @Override
    public float idf(long docFreq, long numDocs) {
        return 1.0f;
    }

    @Override
    public float tf(float freq) {
        return 1.0f;
    }

    @Override
    public float coord(int overlap, int maxOverlap) {
        return 1.0f;
    }

    @Override
    public float lengthNorm(FieldInvertState state) {
        return 1.0f;
    }

    @Override
    public float queryNorm(float sumOfSquaredWeights) {
        return 1.0f;
    }
}

hibernate配置：

<property name="hibernate.search.default.similarity" value="com.search.IgnoreScoringSimilarity"/>

这种方法在90％的时间内都有效，但是，我仍然看到一些奇怪的结果，看起来似乎不合适。我认识到的模式是这些路由（文档）的大小非常大。一条普通路线大约有20-30个路线点，但这些错位结果却有100-150。这使我相信默认的Lucene评分仍在发生（由于文档大小，评分更高）。

在禁用Lucene的评分时，我做错什么了吗？可能还有其他解释吗？


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2020-06-20

共1个答案

小编典典

我可以建议另一种基于自定义结果排序的方法。您可以在答案中阅读它。这个答案有些过时，因此我根据Lucene API 4.10.1修改了此示例。比较器

public abstract class CustomComparator extends FieldComparator<Double> {
    double[] scoring;
    double bottom;
    double topValue;
    private FieldCache.Ints[] currentReaderValues;
    private String[] fields;

    protected abstract double getScore(int[] value);

    public CustomComparator(int hitNum, String[] fields) {
        this.fields = fields;
        scoring = new double[hitNum];
    }

    int[] fromReaders(int doc) {
        int[] result = new int[currentReaderValues.length];
        for (int i = 0; i < result.length; i++) {
            result[i] = currentReaderValues[i].get(doc);
        }
        return result;
    }

    @Override
    public int compare(int slot1, int slot2) {
        return Double.compare(scoring[slot1], scoring[slot2]);
    }

    @Override
    public void setBottom(int slot) {
        this.bottom = scoring[slot];
    }

    @Override
    public void setTopValue(Double top) {
        topValue = top;
    }

    @Override
    public int compareBottom(int doc) throws IOException {
        double v2 = getScore(fromReaders(doc));
        return Double.compare(bottom, v2);
    }

    @Override
    public int compareTop(int doc) throws IOException {
        double docValue = getScore(fromReaders(doc));
        return Double.compare(topValue, docValue);
    }

    @Override
    public void copy(int slot, int doc) throws IOException {
        scoring[slot] = getScore(fromReaders(doc));
    }

    @Override
    public FieldComparator<Double> setNextReader(AtomicReaderContext atomicReaderContext) throws IOException {
        currentReaderValues = new FieldCache.Ints[fields.length];
        for (int i = 0; i < fields.length; i++) {
            currentReaderValues[i] = FieldCache.DEFAULT.getInts(atomicReaderContext.reader(), fields[i], null, false);
        }
        return this;
    }

    @Override
    public Double value(int slot) {
        return scoring[slot];
    }
}

搜索示例

public class SortExample {

    public static void main(String[] args) throws IOException {

        final String[] fields = new String[]{"descriptionLength", "views.views", "nameLength"};

        Sort sort = new Sort(
                new SortField(
                        "",
                        new FieldComparatorSource() {
                            public FieldComparator newComparator(String fieldname, int numHits, int sortPos, boolean reversed) throws IOException {
                                return new CustomComparator(numHits, fields) {
                                    @Override
                                    protected double getScore(int[] value) {
                                        int descriptionLength = value[0];
                                        int views = value[1];
                                        int nameLength = value[2];
                                        return -((descriptionLength > 2000.0 ? 5.0 : 0.0) +
                                                (views > 5000.0 ? 3.0 : 0.0) +
                                                (nameLength > 20.0 ? 1.0 : 0.0));
                                    }
                                };
                            }
                        }
                )
        );

        IndexWriterConfig indexWriterConfig = new IndexWriterConfig(Version.LUCENE_4_10_4, new StandardAnalyzer());
        Directory directory = new RAMDirectory();
        IndexWriter indexWriter = new IndexWriter(directory, indexWriterConfig);

        addDoc(indexWriter, "score 0", 1000, 1000, 10);
        addDoc(indexWriter, "score 5", 3000, 1000, 10);
        addDoc(indexWriter, "score 3", 1000, 6000, 10);
        addDoc(indexWriter, "score 1", 1000, 1000, 30);
        addDoc(indexWriter, "score 4", 1000, 6000, 30);
        addDoc(indexWriter, "score 6", 5000, 1000, 30);
        addDoc(indexWriter, "score 9", 5000, 6000, 30);

        final IndexReader indexReader = DirectoryReader.open(indexWriter, false);
        IndexSearcher indexSearcher = new IndexSearcher(indexReader);
        Query query = new TermQuery(new Term("all", "all"));
        int nDocs = 100;

        final TopDocs search = indexSearcher.search(query, null, nDocs, sort);
        System.out.println("Max " + search.scoreDocs.length + " " + search.getMaxScore());
        for (ScoreDoc sd : search.scoreDocs) {
            Document document = indexReader.document(sd.doc);
            System.out.println(document.getField("name").stringValue());
        }

    }

    private static void addDoc(IndexWriter indexWriter, String name, int descriptionLength, int views, int nameLength) throws IOException {
        Document doc = new Document();
        doc.add(new TextField("name", name, Field.Store.YES));
        doc.add(new TextField("all", "all", Field.Store.YES));
        doc.add(new IntField("descriptionLength", descriptionLength, Field.Store.YES));
        doc.add(new IntField("views.views", views, Field.Store.YES));
        doc.add(new IntField("nameLength", nameLength, Field.Store.YES));
        indexWriter.addDocument(doc);
    }
}

代码将输出

score 9
score 6
score 5
score 4
score 3
score 1
score 0
2020-06-20