概述
我想实现一个Lucene Indexer / Searcher，它使用新的Payload功能，允许将元信息添加到文本中。在我的特定情况下，我将权重（可以理解为％概率，介于0和100之间）添加到概念标签，以便使用它们来覆盖标准的Lucene TF-IDF加权。我对这种行为感到困惑，我相信相似性课程有些问题，我覆盖了，但我无法理解。
示例
当我运行搜索查询（例如“concept：red”）时，我发现每个有效负载始终是通过MyPayloadSimilarity传递的第一个数字（在代码示例中，这是1.0）而不是1.0,50.0和100.0。结果，所有文档都获得相同的有效载荷和相同的分数。但是，数据应该是图片＃1，有效载荷为100.0，其次是图片＃2，其次是图片＃3和非常多样的分数。我无法听到我的声音。
以下是试运行的结果：
Query: concept:red
===> docid: 0 payload: 1.0
===> docid: 1 payload: 1.0
===> docid: 2 payload: 1.0
Number of results:3
-> docid: 3.jpg score: 0.2518424
-> docid: 2.jpg score: 0.2518424
-> docid: 1.jpg score: 0.2518424
有什么问题？我是否误解了Payloads的问题？
代码
附上我作为一个独立的示例共享我的代码，以便您在运行它时尽可能轻松，如果您考虑此选项。
public class PayloadShowcase {
public static void main(String s[]) {
PayloadShowcase p = new PayloadShowcase();
p.run();
}
public void run () {
// Step 1: indexing
MyPayloadIndexer indexer = new MyPayloadIndexer();
indexer.index();
// Step 2: searching
MyPayloadSearcher searcher = new MyPayloadSearcher();
searcher.search("red");
}
public class MyPayloadAnalyzer extends Analyzer {
private PayloadEncoder encoder;
MyPayloadAnalyzer(PayloadEncoder encoder) {
this.encoder = encoder;
}
@Override
protected TokenStreamComponents createComponents(String fieldName, Reader reader) {
Tokenizer source = new WhitespaceTokenizer(reader);
TokenStream filter = new LowerCaseFilter(source);
filter = new DelimitedPayloadTokenFilter(filter, '|', encoder);
return new TokenStreamComponents(source, filter);
}
}
public class MyPayloadIndexer {
public MyPayloadIndexer() {}
public void index() {
try {
Directory dir = FSDirectory.open(new File("D:/data/indices/sandbox"));
Analyzer analyzer = new MyPayloadAnalyzer(new FloatEncoder());
IndexWriterConfig iwconfig = new IndexWriterConfig(Version.LUCENE_4_10_1, analyzer);
iwconfig.setSimilarity(new MyPayloadSimilarity());
iwconfig.setOpenMode(IndexWriterConfig.OpenMode.CREATE);
// load mappings and classifiers
HashMap<String, String> mappings = this.loadDataMappings();
HashMap<String, HashMap> cMaps = this.loadData();
IndexWriter writer = new IndexWriter(dir, iwconfig);
indexDocuments(writer, mappings, cMaps);
writer.close();
} catch (IOException e) {
System.out.println("Exception while indexing: " + e.getMessage());
}
}
private void indexDocuments(IndexWriter writer, HashMap<String, String> fileMappings, HashMap<String, HashMap> concepts) throws IOException {
Set fileSet = fileMappings.keySet();
Iterator<String> iterator = fileSet.iterator();
while (iterator.hasNext()){
// unique file information
String fileID = iterator.next();
String filePath = fileMappings.get(fileID);
// create a new, empty document
Document doc = new Document();
// path of the indexed file
Field pathField = new StringField("path", filePath, Field.Store.YES);
doc.add(pathField);
// lookup all concept probabilities for this fileID
Iterator<String> conceptIterator = concepts.keySet().iterator();
while (conceptIterator.hasNext()){
String conceptName = conceptIterator.next();
HashMap conceptMap = concepts.get(conceptName);
doc.add(new TextField("concept", ("" + conceptName + "|").trim() + (conceptMap.get(fileID) + "").trim(), Field.Store.YES));
}
writer.addDocument(doc);
}
}
public HashMap<String, String> loadDataMappings(){
HashMap<String, String> h = new HashMap<>();
h.put("1", "1.jpg");
h.put("2", "2.jpg");
h.put("3", "3.jpg");
return h;
}
public HashMap<String, HashMap> loadData(){
HashMap<String, HashMap> h = new HashMap<>();
HashMap<String, String> green = new HashMap<>();
green.put("1", "50.0");
green.put("2", "1.0");
green.put("3", "100.0");
HashMap<String, String> red = new HashMap<>();
red.put("1", "100.0");
red.put("2", "50.0");
red.put("3", "1.0");
HashMap<String, String> blue = new HashMap<>();
blue.put("1", "1.0");
blue.put("2", "50.0");
blue.put("3", "100.0");
h.put("green", green);
h.put("red", red);
h.put("blue", blue);
return h;
}
}
class MyPayloadSimilarity extends DefaultSimilarity {
@Override
public float scorePayload(int docID, int start, int end, BytesRef payload) {
float pload = 1.0f;
if (payload != null) {
pload = PayloadHelper.decodeFloat(payload.bytes);
}
System.out.println("===> docid: " + docID + " payload: " + pload);
return pload;
}
}
public class MyPayloadSearcher {
public MyPayloadSearcher() {}
public void search(String queryString) {
try {
IndexReader reader = DirectoryReader.open(FSDirectory.open(new File("D:/data/indices/sandbox")));
IndexSearcher searcher = new IndexSearcher(reader);
searcher.setSimilarity(new PayloadSimilarity());
PayloadTermQuery query = new PayloadTermQuery(new Term("concept", queryString),
new AveragePayloadFunction());
System.out.println("Query: " + query.toString());
TopDocs topDocs = searcher.search(query, 999);
ScoreDoc[] hits = topDocs.scoreDocs;
System.out.println("Number of results:" + hits.length);
// output
for (int i = 0; i < hits.length; i++) {
Document doc = searcher.doc(hits[i].doc);
System.out.println("-> docid: " + doc.get("path") + " score: " + hits[i].score);
}
reader.close();
} catch (Exception e) {
System.out.println("Exception while searching: " + e.getMessage());
}
}
}
}
答案 0 :(得分：1)
在MyPayloadSimilarity，PayloadHelper.decodeFloat来电不正确。在这种情况下，还需要传递payload.offset param，如下所示：
pload = PayloadHelper.decodeFloat(payload.bytes, payload.offset);
我希望它有所帮助。