创建了LowercaseKeywordAnalyzer和不返回结果的TermQuery

本文关键字：结果 TermQuery 返回 LowercaseKeywordAnalyzer 创建 | 更新日期: 2023-09-27 18:04:28

我正在使用PerFieldAnalyzer设置ExactTitle使用新的LowercaseKeywordAnalyzer:

private Analyzer GetDefaultAnalyzer()
    {
        var perFieldAnalyzer = new PerFieldAnalyzerWrapper(new StandardAnalyzer(Version.LUCENE_30));
        perFieldAnalyzer.AddAnalyzer(ReportFields.ExactTitle, new LowercaseKeywordAnalyzer());
...

我正在建立索引，添加字段:

var exactTitleField = new Field(ReportFields.ExactTitle, report.PortalReportTitle, Field.Store.NO,
                                            Field.Index.NOT_ANALYZED);
            exactTitleField.Boost = 10.0f;
            reportDoc.Add(exactTitleField);

当我使用2字示例"test abc"搜索它时，当我对它进行TermQuery搜索时，它无法找到它:

var term = new Term(exactField, "test abc");
var exactQuery = new TermQuery(term);
query.Add(exactQuery,Occur.SHOULD);
var hits = searcher.Search(query, null, HitsLimit, Sort.RELEVANCE);

如果我搜索"Test Abc"，它可以工作。我怎么做才能使这个大小写不敏感的关键字/术语搜索工作?

分析器:

public class LowercaseKeywordAnalyzer : Analyzer
{
    public override TokenStream TokenStream(string fieldName, System.IO.TextReader reader)
    {
        TokenStream tokenStream = new KeywordTokenizer(reader);
        tokenStream = new LowerCaseFilter(tokenStream);
        return tokenStream;
    }
}

创建了LowercaseKeywordAnalyzer和不返回结果的TermQuery

当您在创建字段时指定Field.Index.NOT_ANALYZED时，分析器将不会运行，并且文本将不会转换为小写

切换到Field.Index.ANALYZED

编辑

也许你的索引代码有问题，也不要忘记，如果你在索引时小写，你也将在搜索时小写输入以获得匹配。

由于您手动构建查询，因此您需要自己处理它。理想情况下，您希望在搜索时构建Term之前在字符串上运行相同的Analyzer。

我提供了一个快速的小示例，它可以做你似乎想做的事情，也许它会帮助你找出问题所在。

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using Lucene.Net.Analysis;
using Lucene.Net.Analysis.Standard;
using Lucene.Net.Documents;
using Lucene.Net.Index;
using Lucene.Net.Search;
using Lucene.Net.Store;
namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            RAMDirectory dir = new RAMDirectory();
            var perFieldAnalyzer = new PerFieldAnalyzerWrapper(new StandardAnalyzer(Lucene.Net.Util.Version.LUCENE_30));
            perFieldAnalyzer.AddAnalyzer("ExactTitle", new LowercaseKeywordAnalyzer());
            IndexWriter indexWriter = new IndexWriter(dir, perFieldAnalyzer, IndexWriter.MaxFieldLength.UNLIMITED);
            Document reportDoc = new Document();
            Field exactTitleField = new Field("ExactTitle", 
                                                "Test Abc", 
                                                Field.Store.NO,
                                                Field.Index.ANALYZED);
            reportDoc.Add(exactTitleField);
            indexWriter.AddDocument(reportDoc);
            indexWriter.Commit();
            IndexSearcher searcher = new IndexSearcher(indexWriter.GetReader());
            var term = new Term("ExactTitle", "test abc"); //note: for this to work this way you need to always lower case the search too
            var exactQuery = new TermQuery(term);
            var hits = searcher.Search(exactQuery, null, 25, Sort.RELEVANCE);
            Console.WriteLine(hits.TotalHits); // prints "1"
            Console.ReadLine();
            indexWriter.Close();
        }
        public class LowercaseKeywordAnalyzer : Analyzer
        {
            public override TokenStream TokenStream(string fieldName, System.IO.TextReader reader)
            {
                TokenStream tokenStream = new KeywordTokenizer(reader);
                tokenStream = new LowerCaseFilter(tokenStream);
                return tokenStream;
            }
        }
    }
}
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