尝试使用 Lucene 4.0 计算词频.我的文档频率工作得很好,但不知道如何使用 API 来做词频.这是我的代码:
Trying to calculate term frequency using Lucene 4.0. I got document frequency working just fine, but can't figure out how to do term frequency using the API. Here's the code I have:
private static void addDoc(IndexWriter writer, String content) throws IOException {
FieldType fieldType = new FieldType();
fieldType.setStoreTermVectors(true);
fieldType.setStoreTermVectorPositions(true);
fieldType.setIndexed(true);
fieldType.setIndexOptions(IndexOptions.DOCS_AND_FREQS);
fieldType.setStored(true);
Document doc = new Document();
doc.add(new Field("content", content, fieldType));
writer.addDocument(doc);
}
public static void main(String[] args) throws IOException, ParseException {
Directory directory = new RAMDirectory();
Analyzer analyzer = new WhitespaceAnalyzer(Version.LUCENE_40);
IndexWriterConfig config = new IndexWriterConfig(Version.LUCENE_40, analyzer);
IndexWriter writer = new IndexWriter(directory, config);
addDoc(writer, "Lucene is stupid");
addDoc(writer, "Java is great");
writer.close();
IndexReader reader = DirectoryReader.open(directory);
System.out.println(reader.docFreq(new Term("content", "Lucene")));
reader.close();
}
我尝试过执行类似 reader.getTermVector(0, "content")...
的操作,但找不到仅获取该文档中特定术语频率的方法.
I've tried doing something like reader.getTermVector(0, "content")...
but can't find a method to just get the frequency of a particular term in that document.
谢谢!
K,想通了.您可以从 MultiFields
获取 DocsEnum
对象,然后对其进行迭代.
K, figured it out. You can get a DocsEnum
object from MultiFields
, and then iterate over that.
private static void addDoc(IndexWriter writer, String content) throws IOException {
FieldType fieldType = new FieldType();
fieldType.setStoreTermVectors(true);
fieldType.setStoreTermVectorPositions(true);
fieldType.setIndexed(true);
fieldType.setIndexOptions(IndexOptions.DOCS_AND_FREQS);
fieldType.setStored(true);
Document doc = new Document();
doc.add(new Field("content", content, fieldType));
writer.addDocument(doc);
}
public static void main(String[] args) throws IOException, ParseException {
Directory directory = new RAMDirectory();
Analyzer analyzer = new WhitespaceAnalyzer(Version.LUCENE_40);
IndexWriterConfig config = new IndexWriterConfig(Version.LUCENE_40, analyzer);
IndexWriter writer = new IndexWriter(directory, config);
addDoc(writer, "bla bla bla bleu bleu");
addDoc(writer, "bla bla bla bla");
writer.close();
DirectoryReader reader = DirectoryReader.open(directory);
DocsEnum de = MultiFields.getTermDocsEnum(reader, MultiFields.getLiveDocs(reader), "content", new BytesRef("bla"));
int doc;
while((doc = de.nextDoc()) != DocsEnum.NO_MORE_DOCS) {
System.out.println(de.freq());
}
reader.close();
}
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