Tokenize,使用Lucene和Java删除停用词

Question

我试图用Lucene标记并删除txt文件中的停用词.我有这个:

public String removeStopWords(String string) throws IOException {

Set<String> stopWords = new HashSet<String>();
    stopWords.add("a");
    stopWords.add("an");
    stopWords.add("I");
    stopWords.add("the");

    TokenStream tokenStream = new StandardTokenizer(Version.LUCENE_43, new StringReader(string));
    tokenStream = new StopFilter(Version.LUCENE_43, tokenStream, stopWords);

    StringBuilder sb = new StringBuilder();

    CharTermAttribute token = tokenStream.getAttribute(CharTermAttribute.class);
    while (tokenStream.incrementToken()) {
        if (sb.length() > 0) {
            sb.append(" ");
        }
        sb.append(token.toString());
    System.out.println(sb);    
    }
    return sb.toString();
}}

我的主要看起来像这样:

    String file = "..../datatest.txt";

    TestFileReader fr = new TestFileReader();
    fr.imports(file);
    System.out.println(fr.content);

    String text = fr.content;

    Stopwords stopwords = new Stopwords();
    stopwords.removeStopWords(text);
    System.out.println(stopwords.removeStopWords(text));

这给了我一个错误,但我无法弄清楚为什么.

Answer 1

我有同样的问题.要使用Lucene您删除停用词,可以使用该方法使用默认停止设置EnglishAnalyzer.getDefaultStopSet();.否则,您可以创建自己的自定义停用词列表.

下面的代码显示了您的正确版本removeStopWords():

public static String removeStopWords(String textFile) throws Exception {
    CharArraySet stopWords = EnglishAnalyzer.getDefaultStopSet();
    TokenStream tokenStream = new StandardTokenizer(Version.LUCENE_48, new StringReader(textFile.trim()));

    tokenStream = new StopFilter(Version.LUCENE_48, tokenStream, stopWords);
    StringBuilder sb = new StringBuilder();
    CharTermAttribute charTermAttribute = tokenStream.addAttribute(CharTermAttribute.class);
    tokenStream.reset();
    while (tokenStream.incrementToken()) {
        String term = charTermAttribute.toString();
        sb.append(term + " ");
    }
    return sb.toString();
}

要使用自定义停用词列表,请使用以下命令:

//CharArraySet stopWords = EnglishAnalyzer.getDefaultStopSet(); //this is Lucene set 
final List<String> stop_Words = Arrays.asList("fox", "the");
final CharArraySet stopSet = new CharArraySet(Version.LUCENE_48, stop_Words, true);

Answer 2

您可以尝试在调用 tokenStream.incrementToken() 之前调用 tokenStream.reset()