KeywordAnalyzer and LowerCaseFilter/LowerCaseTokenizer

问题

I want to build my own analyzer that uses both filters/tokenizers.

I mean, the same field is Keyword (entire stream as a single token) and lowercase

If KeywordAnalyzer use only, the value of field keeps the case-insensitive. If I use LowerCaseTokenizer or LowerCaseFilter I have to combine them with other analyzers that do the same thing KeywordAnalyzer (separated by no letter, by spaces, remove stop-words, etc.)

The question is: Is there any way to make that field as Keyword (entire stream as a single token) and that lowercase using filters or analyzers Lucene or tokenizers?

(google translated, sorry about errors)

回答1:

This should work:

public final class YourAnalyzer extends ReusableAnalyzerBase { 

  @Override
  protected TokenStreamComponents createComponents(final String fieldName, final Reader reader) {
    final TokenStream source = new KeywordTokenizer(reader);
    return new TokenStreamComponents(source, new LowercaseFilter(Version.LUCENE_36, source));
  }
}

回答2:

In Lucene 3.6.2 it must look like this:

import org.apache.lucene.analysis.KeywordAnalyzer;
import org.apache.lucene.analysis.KeywordTokenizer;
import org.apache.lucene.analysis.LowerCaseFilter;
import org.apache.lucene.analysis.LowerCaseTokenizer;
import org.apache.lucene.analysis.ReusableAnalyzerBase;
import org.apache.lucene.analysis.Tokenizer;
import org.apache.lucene.util.Version;

public class YourAnalyzer extends ReusableAnalyzerBase {

    private final Version version;

    public YourAnalyzer(final Version version) {
        super();
        this.version = version;
    }

    @Override
    protected TokenStreamComponents createComponents(final String fieldName, final Reader reader) {
        final Tokenizer source = new KeywordTokenizer(reader);
        return new TokenStreamComponents(source, new LowerCaseFilter(this.version, source));
    }

}

来源：https://stackoverflow.com/questions/11782783/keywordanalyzer-and-lowercasefilter-lowercasetokenizer