Lucene搜索问题

Question

I have built an index on my database rows (Each row as a document) which are of unicode type in MySQL(ie Charset: utf8 and Collation: utf8-bin). But When I search any word English or non-English it gives me no answers. It says:

0 total matching documents

My code is the demo code of lucene for search except that I have changed field names to my inserted column names. Anyway, it prints this message before reaching that part of code. And also I have changed the read query encoding to UTF-8.

I have checked the reading of database part. It's OK.

What's the problem?

If it helps, here is my insertion code:

static void indexDocs(IndexWriter writer, Connection conn) throws SQLException, CorruptIndexException, IOException {
    String sql = "select id, name, description, text from users";
    Statement stmt = conn.createStatement();

    ResultSet rs = stmt.executeQuery(sql);
    while (rs.next()) {
        Document d = new Document();
        d.add(new Field("id", rs.getString("id"), Field.Store.YES, Field.Index.NOT_ANALYZED));
        d.add(new Field("name", rs.getString("name"), Field.Store.NO, Field.Index.NOT_ANALYZED));
        String tmp = rs.getString("description");
        if (tmp == null) {
            tmp = "";
        }
        d.add(new Field("description", tmp, Field.Store.NO, Field.Index.ANALYZED));
        tmp = rs.getString("text");
        if (tmp == null) {
            tmp = "";
        }
        d.add(new Field("text", tmp, Field.Store.NO, Field.Index.ANALYZED));
        writer.addDocument(d);
    }
}

Also this is my search code:

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Date;

import org.apache.lucene.analysis.Analyzer;
import org.apache.lucene.analysis.standard.StandardAnalyzer;
import org.apache.lucene.document.Document;
import org.apache.lucene.index.FilterIndexReader;
import org.apache.lucene.index.IndexReader;
import org.apache.lucene.queryParser.QueryParser;
import org.apache.lucene.search.Collector;
import org.apache.lucene.search.IndexSearcher;
import org.apache.lucene.search.Query;
import org.apache.lucene.search.ScoreDoc;
import org.apache.lucene.search.Scorer;
import org.apache.lucene.search.Searcher;
import org.apache.lucene.search.TopScoreDocCollector;
import org.apache.lucene.store.FSDirectory;
import org.apache.lucene.util.Version;

/** Simple command-line based search demo. */
public class Search {

    /** Use the norms from one field for all fields.  Norms are read into memory,
     * using a byte of memory per document per searched field.  This can cause
     * search of large collections with a large number of fields to run out of
     * memory.  If all of the fields contain only a single token, then the norms
     * are all identical, then single norm vector may be shared. */
    private static class OneNormsReader extends FilterIndexReader {

        private String field;

        public OneNormsReader(IndexReader in, String field) {
            super(in);
            this.field = field;
        }

        @Override
        public byte[] norms(String field) throws IOException {
            return in.norms(this.field);
        }
    }

    private Search() {
    }

    /** Simple command-line based search demo. */
    public static void main(String[] args) throws Exception {
        String usage =
                "Usage:\tjava org.apache.lucene.demo.SearchFiles [-index dir] [-field f] [-repeat n] [-queries file] [-raw] [-norms field] [-paging hitsPerPage]";
        usage += "\n\tSpecify 'false' for hitsPerPage to use streaming instead of paging search.";
        if (args.length > 0 && ("-h".equals(args[0]) || "-help".equals(args[0]))) {
            System.out.println(usage);
            System.exit(0);
        }

        String index = "index";
        String field = "contents";
        String queries = null;
        int repeat = 0;
        boolean raw = false;
        String normsField = null;
        boolean paging = true;
        int hitsPerPage = 10;

        for (int i = 0; i < args.length; i++) {
            if ("-index".equals(args[i])) {
                index = args[i + 1];
                i++;
            } else if ("-field".equals(args[i])) {
                field = args[i + 1];
                i++;
            } else if ("-queries".equals(args[i])) {
                queries = args[i + 1];
                i++;
            } else if ("-repeat".equals(args[i])) {
                repeat = Integer.parseInt(args[i + 1]);
                i++;
            } else if ("-raw".equals(args[i])) {
                raw = true;
            } else if ("-norms".equals(args[i])) {
                normsField = args[i + 1];
                i++;
            } else if ("-paging".equals(args[i])) {
                if (args[i + 1].equals("false")) {
                    paging = false;
                } else {
                    hitsPerPage = Integer.parseInt(args[i + 1]);
                    if (hitsPerPage == 0) {
                        paging = false;
                    }
                }
                i++;
            }
        }

        IndexReader reader = IndexReader.open(FSDirectory.open(new File(index)), true); // only searching, so read-only=true

        if (normsField != null) {
            reader = new OneNormsReader(reader, normsField);
        }

        Searcher searcher = new IndexSearcher(reader);
        Analyzer analyzer = new StandardAnalyzer(Version.LUCENE_CURRENT);

        BufferedReader in = null;
        if (queries != null) {
            in = new BufferedReader(new FileReader(queries));
        } else {
            in = new BufferedReader(new InputStreamReader(System.in, "UTF-8"));
        }
        QueryParser parser = new QueryParser(Version.LUCENE_CURRENT, field, analyzer);
        while (true) {
            if (queries == null) // prompt the user
            {
                System.out.println("Enter query: ");
            }

            String line = in.readLine();
            line = new String(line.getBytes("8859_1"), "UTF8");

            if (line == null || line.length() == -1) {
                break;
            }

            line = line.trim();
            if (line.length() == 0) {
                break;
            }

            Query query = parser.parse(line);
            System.out.println("Searching for: " + query.toString(field));


            if (repeat > 0) {                           // repeat & time as benchmark
                Date start = new Date();
                for (int i = 0; i < repeat; i++) {
                    searcher.search(query, null, 100);
                }
                Date end = new Date();
                System.out.println("Time: " + (end.getTime() - start.getTime()) + "ms");
            }

            if (paging) {
                doPagingSearch(in, searcher, query, hitsPerPage, raw, queries == null);
            } else {
                doStreamingSearch(searcher, query);
            }
        }
        reader.close();
    }

    /**
     * This method uses a custom HitCollector implementation which simply prints out
     * the docId and score of every matching document.
     *
     *  This simulates the streaming search use case, where all hits are supposed to
     *  be processed, regardless of their relevance.
     */
    public static void doStreamingSearch(final Searcher searcher, Query query) throws IOException {
        Collector streamingHitCollector = new Collector() {

            private Scorer scorer;
            private int docBase;

            // simply print docId and score of every matching document
            @Override
            public void collect(int doc) throws IOException {
                System.out.println("doc=" + doc + docBase + " score=" + scorer.score());
            }

            @Override
            public boolean acceptsDocsOutOfOrder() {
                return true;
            }

            @Override
            public void setNextReader(IndexReader reader, int docBase)
                    throws IOException {
                this.docBase = docBase;
            }

            @Override
            public void setScorer(Scorer scorer) throws IOException {
                this.scorer = scorer;
            }
        };

        searcher.search(query, streamingHitCollector);
    }

    /**
     * This demonstrates a typical paging search scenario, where the search engine presents
     * pages of size n to the user. The user can then go to the next page if interested in
     * the next hits.
     *
     * When the query is executed for the first time, then only enough results are collected
     * to fill 5 result pages. If the user wants to page beyond this limit, then the query
     * is executed another time and all hits are collected.
     *
     */
    public static void doPagingSearch(BufferedReader in, Searcher searcher, Query query,
            int hitsPerPage, boolean raw, boolean interactive) throws IOException {

        // Collect enough docs to show 5 pages
        TopScoreDocCollector collector = TopScoreDocCollector.create(
                5 * hitsPerPage, false);
        searcher.search(query, collector);
        ScoreDoc[] hits = collector.topDocs().scoreDocs;

        int numTotalHits = collector.getTotalHits();
        System.out.println(numTotalHits + " total matching documents");

        int start = 0;
        int end = Math.min(numTotalHits, hitsPerPage);

        while (true) {
            if (end > hits.length) {
                System.out.println("Only results 1 - " + hits.length + " of " + numTotalHits + " total matching documents collected.");
                System.out.println("Collect more (y/n) ?");
                String line = in.readLine();
                if (line.length() == 0 || line.charAt(0) == 'n') {
                    break;
                }

                collector = TopScoreDocCollector.create(numTotalHits, false);
                searcher.search(query, collector);
                hits = collector.topDocs().scoreDocs;
            }

            end = Math.min(hits.length, start + hitsPerPage);

            for (int i = start; i < end; i++) {
                if (raw) {                              // output raw format
                    System.out.println("doc=" + hits[i].doc + " score=" + hits[i].score);
                    continue;
                }

                Document doc = searcher.doc(hits[i].doc);
                String id = doc.get("id");
                if (id != null) {
                    System.out.println((i + 1) + ". " + id);
                    String name = doc.get("name");
                    if (name != null) {
                        System.out.println("   name: " + doc.get("name"));
                    }
                    String description = doc.get("description");
                    if (description != null) {
                        System.out.println("   description: " + doc.get("description"));
                    }
                    String text= doc.get("text");
                    if (text != null) {
                        System.out.println("   text: " + doc.get("text"));
                    }
                } else {
                    System.out.println((i + 1) + ". " + "No path for this document");
                }

            }

            if (!interactive) {
                break;
            }

            if (numTotalHits >= end) {
                boolean quit = false;
                while (true) {
                    System.out.print("Press ");
                    if (start - hitsPerPage >= 0) {
                        System.out.print("(p)revious page, ");
                    }
                    if (start + hitsPerPage < numTotalHits) {
                        System.out.print("(n)ext page, ");
                    }
                    System.out.println("(q)uit or enter number to jump to a page.");

                    String line = in.readLine();
                    if (line.length() == 0 || line.charAt(0) == 'q') {
                        quit = true;
                        break;
                    }
                    if (line.charAt(0) == 'p') {
                        start = Math.max(0, start - hitsPerPage);
                        break;
                    } else if (line.charAt(0) == 'n') {
                        if (start + hitsPerPage < numTotalHits) {
                            start += hitsPerPage;
                        }
                        break;
                    } else {
                        int page = Integer.parseInt(line);
                        if ((page - 1) * hitsPerPage < numTotalHits) {
                            start = (page - 1) * hitsPerPage;
                            break;
                        } else {
                            System.out.println("No such page");
                        }
                    }
                }
                if (quit) {
                    break;
                }
                end = Math.min(numTotalHits, start + hitsPerPage);
            }

        }

    }
}

Thank you.

Answer 1

I found out. I should specify the column which I want to search. eg For searching in text field I should say: "text:MyWord"