在Lucene中对位置匹配词的访问

Question

给定文档中的术语匹配，访问匹配词的最佳方式是什么？我读过这篇文章http://searchhub.org//2009/05/26/accessing-words-around-a-position-match-in-lucene/，但问题是Lucene API自这篇文章（2009）以来完全改变了，有人能告诉我在Lucene的新版本中如何做到这一点吗，比如Lucene4.6.1？

编辑：

public class TermVectorFun {
  public static String[] DOCS = {
    "The quick red fox jumped over the lazy brown dogs.",
    "Mary had a little lamb whose fleece was white as snow.",
    "Moby Dick is a story of a whale and a man obsessed.",
    "The robber wore a black fleece jacket and a baseball cap.",
    "The English Springer Spaniel is the best of all dogs.",
    "The fleece was green and red",
        "History looks fondly upon the story of the golden fleece, but most people don't agree"
  };

  public static void main(String[] args) throws IOException {
    RAMDirectory ramDir = new RAMDirectory();
    IndexWriterConfig config = new IndexWriterConfig(Version.LUCENE_46, new StandardAnalyzer(Version.LUCENE_46));
    config.setOpenMode(IndexWriterConfig.OpenMode.CREATE);
    //Index some made up content
    IndexWriter writer = new IndexWriter(ramDir, config);
    for (int i = 0; i < DOCS.length; i++) {
      Document doc = new Document();
      Field id = new Field("id", "doc_" + i, Field.Store.YES, Field.Index.NOT_ANALYZED_NO_NORMS);
      doc.add(id);
      //Store both position and offset information
      Field text = new Field("content", DOCS[i], Field.Store.NO, Field.Index.ANALYZED, Field.TermVector.WITH_POSITIONS_OFFSETS);
      doc.add(text);
      writer.addDocument(doc);
    }
    writer.close();
    //Get a searcher

    DirectoryReader dirReader = DirectoryReader.open(ramDir);
    IndexSearcher searcher = new IndexSearcher(dirReader);
    // Do a search using SpanQuery
    SpanTermQuery fleeceQ = new SpanTermQuery(new Term("content", "fleece"));
    TopDocs results = searcher.search(fleeceQ, 10);
    for (int i = 0; i < results.scoreDocs.length; i++) {
      ScoreDoc scoreDoc = results.scoreDocs[i];
      System.out.println("Score Doc: " + scoreDoc);
    }
    IndexReader reader = searcher.getIndexReader();
    Spans spans = fleeceQ.getSpans(reader.leaves().get(0), null, new LinkedHashMap<Term, TermContext>());
    int window = 2;//get the words within two of the match
    while (spans.next() == true) {
      int start = spans.start() - window;
      int end = spans.end() + window;
      Map<Integer, String> entries = new TreeMap<Integer, String>();

      System.out.println("Doc: " + spans.doc() + " Start: " + start + " End: " + end);
      Fields fields = reader.getTermVectors(spans.doc());
      Terms terms = fields.terms("content");

      TermsEnum termsEnum = terms.iterator(null);
      BytesRef text;
      while((text = termsEnum.next()) != null) {        
        //could store the BytesRef here, but String is easier for this example
        String s = new String(text.bytes, text.offset, text.length);
        DocsAndPositionsEnum positionsEnum = termsEnum.docsAndPositions(null, null);
        if (positionsEnum.nextDoc() != DocIdSetIterator.NO_MORE_DOCS) {
          int i = 0;
          int position = -1;
          while (i < positionsEnum.freq() && (position = positionsEnum.nextPosition()) != -1) {
            if (position >= start && position <= end) {
              entries.put(position, s);
            }
            i++;
          }
        }
      }
      System.out.println("Entries:" + entries);
    }
  }
}

Answer 1

使用荧光笔。highlighter.getBestFragment可用于获取包含最佳匹配的文本的一部分。类似于：

TopDocs docs = searcher.search(query, maxdocs);
Document firstDoc = search.doc(docs.scoreDocs[0].doc);

Scorer scorer = new QueryScorer(query)
Highlighter highlighter = new Highlighter(scorer);
highlighter.GetBestFragment(myAnalyzer, fieldName, firstDoc.get(fieldName));