如何在QueryParser中合并多个字段?

问题描述

Dim qp1 As New QueryParser("filename", New StandardAnalyzer())
Dim qp2 As New QueryParser("filetext", New StandardAnalyzer())
.
.

我正在使用'Lucene.Net'库，并且有以下问题.

I am using the 'Lucene.Net' library and have the following question.

不是创建两个单独的QueryParser对象并使用它们来获取两个Hits对象，而是可以使用单个QueryParser对象在两个字段上执行搜索，因此我只有一个Hits对象，这给了我每个文档的总分?

Instead of creating two separate QueryParser objects and using them to obtain two Hits objects, is it possible perform a search on both fields using a single QueryParser object, so that I have only one Hits object which gives me the overall score of each Document?

推荐答案

共有3种方法.

第一种方法是手动构造查询，这是QueryParser在内部执行的操作.这是执行此操作最强大的方法，并且意味着如果要阻止访问QueryParser的某些更奇特的功能，则不必解析用户输入:

The first way is to construct a query manually, this is what QueryParser is doing internally. This is the most powerful way to do it, and means that you don't have to parse the user input if you want to prevent access to some of the more exotic features of QueryParser:

IndexReader reader = IndexReader.Open("<lucene dir>");
Searcher searcher = new IndexSearcher(reader);

BooleanQuery booleanQuery = new BooleanQuery();
Query query1 = new TermQuery(new Term("filename", "<text>"));
Query query2 = new TermQuery(new Term("filetext", "<text>"));
booleanQuery.add(query1, BooleanClause.Occur.SHOULD);
booleanQuery.add(query2, BooleanClause.Occur.SHOULD);
// Use BooleanClause.Occur.MUST instead of BooleanClause.Occur.SHOULD
// for AND queries
Hits hits = searcher.Search(booleanQuery);

第二种方法是使用MultiFieldQueryParser，其行为类似于QueryParser，除了可以搜索多个字段之外，还可以访问其具有的所有功能.

The second way is to use MultiFieldQueryParser, this behaves like QueryParser, allowing access to all the power that it has, except that it will search over multiple fields.

IndexReader reader = IndexReader.Open("<lucene dir>");
Searcher searcher = new IndexSearcher(reader);

Analyzer analyzer = new StandardAnalyzer();
MultiFieldQueryParser queryParser = new MultiFieldQueryParser(
                                        new string[] {"filename", "filetext"},
                                        analyzer);

Hits hits = searcher.Search(queryParser.parse("<text>"));

最后一种方法是使用QueryParser的特殊语法请参见此处.

The final way is to use the special syntax of QueryParser see here.

IndexReader reader = IndexReader.Open("<lucene dir>");
Searcher searcher = new IndexSearcher(reader);

Analyzer analyzer = new StandardAnalyzer();
QueryParser queryParser = new QueryParser("<default field>", analyzer);
// <default field> is the field that QueryParser will search if you don't
// prefix it with a field.
string special = "filename:" + text + " OR filetext:" + text;

Hits hits = searcher.Search(queryParser.parse(special));

您的另一种选择是在索引名为filename和text的内容时创建一个新字段，您可以在其中放置 filename和filetext的内容，然后只需要搜索一个字段即可.

Your other option is to create new field when you index your content called filenameandtext, into which you can place the contents of both filename and filetext, then you only have to search one field.

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