Question

鉴于文档{'foo'，'bar'，'baz'}，我想使用SpanNearQuery与令牌匹配{'baz'，'extra'}

但这失败了。

我该如何解决这个问题？

样品测试（使用lucene 2.9.1），结果如下：

givenSingleMatch - PASS
givenTwoMatches - PASS
givenThreeMatches - PASS
givenSingleMatch_andExtraTerm - FAIL

...

import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.document.Field;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.index.IndexWriter;
import org.apache.lucene.index.Term;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.TopDocs;
import org.apache.lucene.search.spans.SpanNearQuery;
import org.apache.lucene.search.spans.SpanQuery;
import org.apache.lucene.search.spans.SpanTermQuery;
import org.apache.lucene.store.RAMDirectory;
import org.apache.lucene.util.Version;
import org.junit.After;
import org.junit.Assert;
import org.junit.Before;
import org.junit.Test;

import java.io.IOException;

public class SpanNearQueryTest {

    private RAMDirectory directory = null;

    private static final String BAZ = "baz";
    private static final String BAR = "bar";
    private static final String FOO = "foo";
    private static final String TERM_FIELD = "text";

    @Before
    public void given() throws IOException {
        directory = new RAMDirectory();
        IndexWriter writer = new IndexWriter(
                directory,
                new StandardAnalyzer(Version.LUCENE_29),
                IndexWriter.MaxFieldLength.UNLIMITED);

        Document doc = new Document();
        doc.add(new Field(TERM_FIELD, FOO, Field.Store.NO, Field.Index.ANALYZED));
        doc.add(new Field(TERM_FIELD, BAR, Field.Store.NO, Field.Index.ANALYZED));
        doc.add(new Field(TERM_FIELD, BAZ, Field.Store.NO, Field.Index.ANALYZED));

        writer.addDocument(doc);
        writer.commit();
        writer.optimize();
        writer.close();
    }

    @After
    public void cleanup() {
        directory.close();
    }

    @Test
    public void givenSingleMatch() throws IOException {

        SpanNearQuery spanNearQuery = new SpanNearQuery(
                new SpanQuery[] {
                        new SpanTermQuery(new Term(TERM_FIELD, FOO))
                }, Integer.MAX_VALUE, false);

        TopDocs topDocs = new IndexSearcher(IndexReader.open(directory)).search(spanNearQuery, 100);

        Assert.assertEquals("Should have made a match.", 1, topDocs.scoreDocs.length);
    }

    @Test
    public void givenTwoMatches() throws IOException {

        SpanNearQuery spanNearQuery = new SpanNearQuery(
                new SpanQuery[] {
                        new SpanTermQuery(new Term(TERM_FIELD, FOO)),
                        new SpanTermQuery(new Term(TERM_FIELD, BAR))
                }, Integer.MAX_VALUE, false);

        TopDocs topDocs = new IndexSearcher(IndexReader.open(directory)).search(spanNearQuery, 100);

        Assert.assertEquals("Should have made a match.", 1, topDocs.scoreDocs.length);
    }

    @Test
    public void givenThreeMatches() throws IOException {

        SpanNearQuery spanNearQuery = new SpanNearQuery(
                new SpanQuery[] {
                        new SpanTermQuery(new Term(TERM_FIELD, FOO)),
                        new SpanTermQuery(new Term(TERM_FIELD, BAR)),
                        new SpanTermQuery(new Term(TERM_FIELD, BAZ))
                }, Integer.MAX_VALUE, false);

        TopDocs topDocs = new IndexSearcher(IndexReader.open(directory)).search(spanNearQuery, 100);

        Assert.assertEquals("Should have made a match.", 1, topDocs.scoreDocs.length);
    }

    @Test
    public void givenSingleMatch_andExtraTerm() throws IOException {

        SpanNearQuery spanNearQuery = new SpanNearQuery(
                new SpanQuery[] {
                        new SpanTermQuery(new Term(TERM_FIELD, BAZ)),
                        new SpanTermQuery(new Term(TERM_FIELD, "EXTRA"))
                },
                Integer.MAX_VALUE, false);

        TopDocs topDocs = new IndexSearcher(IndexReader.open(directory)).search(spanNearQuery, 100);

        Assert.assertEquals("Should have made a match.", 1, topDocs.scoreDocs.length);
    }
}

Answer 1

SpanNearQuery可让您查找彼此相距一定距离的术语。

示例（来自http://www.lucidimagination.com/blog/2009/07/18/the-spanquery/）：

假设我们想在5以内找到lucene 道格的位置，道格跟随 lucene（订购事项） - 你可以使用以下SpanQuery：

new SpanNearQuery(new SpanQuery[] {
  new SpanTermQuery(new Term(FIELD, "lucene")),
  new SpanTermQuery(new Term(FIELD, "doug"))},
  5,
  true);

alt text http://www.lucidimagination.com/blog/wp-content/uploads/2009/07/spanquery-dia1.png

在这个示例文本中，Lucene在其中道格的3个

但是对于你的例子，我能看到的唯一匹配是你的查询和目标文档都有“cd”（我假设所有这些术语都在一个字段中）。在这种情况下，您不需要使用任何特殊的查询类型。使用标准机制，您将获得一些非零加权，因为它们在同一个字段中都包含相同的术语。

编辑3 - 为了回应最新评论，答案是你不能使用SpanNearQuery做除了预期之外的任何事情，这是为了找出是否多个文档中的术语出现在彼此的特定数量的位置内。我不知道你的具体用例/预期结果是什么（随意发布），但在最后一种情况下，你只想知道一个或多个（“BAZ”，“EXTRA”）是否在文档，BooleanQuery将正常工作。

编辑4 - 现在你已经发布了你的用例，我明白你想要做什么。您可以通过以下方式执行此操作：使用上述BooleanQuery组合您想要的各个字词以及SpanNearQuery，并在SpanNearQuery上设置提升。

因此，文本形式的查询看起来像：

BAZ OR EXTRA OR "BAZ EXTRA"~100^5

（作为一个例子 - 这将匹配包含“BAZ”或“EXTRA”的所有文件，但是对于“BAZ”和“EXTRA”在彼此的100个地方之间发生的文件分配更高的分数;调整位置这个例子来自Solr食谱，因此它可能不会在Lucene中解析，或者可能会产生不良结果。这没关系，因为在下一节我将向您展示如何使用API构建它。

以编程方式，您可以按如下方式构建它：

Query top = new BooleanQuery();

// Construct the terms since they will be used more than once
Term bazTerm = new Term("Field", "BAZ");
Term extraTerm = new Term("Field", "EXTRA");

// Add each term as "should" since we want a partial match
top.add(new TermQuery(bazTerm), BooleanClause.Occur.SHOULD);
top.add(new TermQuery(extraTerm), BooleanClause.Occur.SHOULD);

// Construct the SpanNearQuery, with slop 100 - a document will get a boost only
// if BAZ and EXTRA occur within 100 places of each other.  The final parameter means
// that BAZ must occur before EXTRA.
SpanNearQuery spanQuery = new SpanNearQuery(
                              new SpanQuery[] { new SpanTermQuery(bazTerm), 
                                                new SpanTermQuery(extraTerm) }, 
                              100, true);

// Give it a boost of 5 since it is more important that the words are together
spanQuery.setBoost(5f);

// Add it as "should" since we want a match even when we don't have proximity
top.add(spanQuery, BooleanClause.Occur.SHOULD);

希望有所帮助！在将来，尝试通过准确发布您期望的结果开始 - 即使对您来说显而易见，也可能不是读者，并且明确可以避免必须来回多次。

Lucene SpanNearQuery部分匹配

1 个答案: