问题
I am trying to tokenize and remove stop words from a txt file with Lucene. I have this:
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();
}}
My main looks like this:
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));
This is giving me an error but I can't figure out why.
回答1:
I had The same problem. To remove stop-words using Lucene
you could either use their Default Stop Set using the method EnglishAnalyzer.getDefaultStopSet();
. Otherwise, you could create your own custom stop-words list.
The code below shows the correct version of your 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();
}
To use a custom list of stop words use the following:
//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);
回答2:
you may try to call tokenStream.reset() before calling tokenStream.incrementToken()
来源:https://stackoverflow.com/questions/17625385/tokenize-remove-stop-words-using-lucene-with-java