java - 从命中/命中迁移到 TopDocs/TopDocCollector

Question

我有这样的现有代码:

final Term t = /* ... */;
final Iterator i = searcher.search( new TermQuery( t ) ).iterator();
while ( i.hasNext() ) {
    Hit hit = (Hit)i.next();
    // "FILE" is the field that recorded the original file indexed
    File f = new File( hit.get( "FILE" ) );
    // ...
}

我不清楚如何使用 TopDocs/TopDocCollector 重写代码以及如何迭代所有结果。

Answer 1

基本上，您必须决定对预期结果数量的限制。然后在生成的 TopDocs 中遍历所有 ScoreDoc。

final MAX_RESULTS = 10000;
final Term t = /* ... */;
final TopDocs topDocs = searcher.search( new TermQuery( t ), MAX_RESULTS );
for ( ScoreDoc scoreDoc : topDocs.scoreDocs ) {
    Document doc = searcher.doc( scoreDoc.doc )
    // "FILE" is the field that recorded the original file indexed
    File f = new File( doc.get( "FILE" ) );
    // ...
}

这基本上就是 Hits 类所做的，只是它将限制设置为 50 个结果，如果您迭代超过该限制，则会重复搜索，即通常很浪费。这就是它被弃用的原因。

添加:如果对结果的数量没有限制，则应使用 HitCollector:

final Term t = /* ... */;
final ArrayList<Integer> docs = new ArrayList<Integer>();
searcher.search( new TermQuery( t ), new HitCollector() {
    public void collect(int doc, float score) {
        docs.add(doc);
    }
});

for(Integer docid : docs) {
    Document doc = searcher.doc(docid);
    // "FILE" is the field that recorded the original file indexed
    File f = new File( doc.get( "FILE" ) );
    // ...
}