我想使用Lucene.Net 4.8实现可搜索的索引,该索引可以为用户提供针对单个单词和短语的建议/自动完成功能。
索引已成功创建;这些建议是我拖延的地方。
版本4.8似乎引入了许多重大更改,而我发现没有可用的示例可用。
LuceneVersion
是这样的:
private readonly LuceneVersion LuceneVersion = LuceneVersion.LUCENE_48;
解决方案1
I've tried this,但不能越过reader.Terms
:
public void TryAutoComplete()
{
var analyzer = new EnglishAnalyzer(LuceneVersion);
var config = new IndexWriterConfig(LuceneVersion, analyzer);
RAMDirectory dir = new RAMDirectory();
using (IndexWriter iw = new IndexWriter(dir, config))
{
Document d = new Document();
TextField f = new TextField("text","",Field.Store.YES);
d.Add(f);
f.SetStringValue("abc");
iw.AddDocument(d);
f.SetStringValue("colorado");
iw.AddDocument(d);
f.SetStringValue("coloring book");
iw.AddDocument(d);
iw.Commit();
using (IndexReader reader = iw.GetReader(false))
{
TermEnum terms = reader.Terms(new Term("text", "co"));
int maxSuggestsCpt = 0;
// will print:
// colorado
// coloring book
do
{
Console.WriteLine(terms.Term.Text);
maxSuggestsCpt++;
if (maxSuggestsCpt >= 5)
break;
}
while (terms.Next() && terms.Term.Text.StartsWith("co"));
}
}
}
reader.Terms
no longer exists。作为Lucene的新手,目前尚不清楚如何重构它。
解决方案2
尝试this时,我抛出了错误:
public void TryAutoComplete2()
{
using(var analyzer = new EnglishAnalyzer(LuceneVersion))
{
IndexWriterConfig config = new IndexWriterConfig(LuceneVersion, analyzer);
RAMDirectory dir = new RAMDirectory();
using(var iw = new IndexWriter(dir,config))
{
Document d = new Document()
{
new TextField("text", "this is a document with a some words",Field.Store.YES),
new Int32Field("id", 42, Field.Store.YES)
};
iw.AddDocument(d);
iw.Commit();
using (IndexReader reader = iw.GetReader(false))
using (SpellChecker speller = new SpellChecker(new RAMDirectory()))
{
//ERROR HERE!!!
speller.IndexDictionary(new LuceneDictionary(reader, "text"), config, false);
string[] suggestions = speller.SuggestSimilar("dcument", 5);
IndexSearcher searcher = new IndexSearcher(reader);
foreach (string suggestion in suggestions)
{
TopDocs docs = searcher.Search(new TermQuery(new Term("text", suggestion)), null, Int32.MaxValue);
foreach (var doc in docs.ScoreDocs)
{
System.Diagnostics.Debug.WriteLine(searcher.Doc(doc.Doc).Get("id"));
}
}
}
}
}
}
调试时,speller.IndexDictionary(new LuceneDictionary(reader, "text"), config, false);
会引发The object cannot be set twice!
错误,我无法解释。
欢迎任何想法。
我想返回给定输入的建议术语列表,而不是文档或其全部内容。
例如,如果文档包含“你好,我的名字叫克拉克。我来自亚特兰大”,而我提交了“ Atl”,那么“ Atlanta”应该作为建议。
答案 0 :(得分:1)
如果我对您的理解正确,则可能会使索引设计有些复杂。如果您的目标是使用Lucene自动完成完成,则希望创建一个您认为完成的术语的索引。然后只需使用带有部分单词或短语的PrefixQuery来查询索引。
using Lucene.Net.Analysis;
using Lucene.Net.Analysis.En;
using Lucene.Net.Documents;
using Lucene.Net.Index;
using Lucene.Net.Search;
using Lucene.Net.Store;
using Lucene.Net.Util;
using System;
using System.Linq;
namespace LuceneDemoApp
{
class LuceneAutoCompleteIndex : IDisposable
{
const LuceneVersion Version = LuceneVersion.LUCENE_48;
RAMDirectory Directory;
Analyzer Analyzer;
IndexWriterConfig WriterConfig;
private void IndexDoc(IndexWriter writer, string term)
{
Document doc = new Document();
doc.Add(new StringField(FieldName, term, Field.Store.YES));
writer.AddDocument(doc);
}
public LuceneAutoCompleteIndex(string fieldName, int maxResults)
{
FieldName = fieldName;
MaxResults = maxResults;
Directory = new RAMDirectory();
Analyzer = new EnglishAnalyzer(Version);
WriterConfig = new IndexWriterConfig(Version, Analyzer);
WriterConfig.OpenMode = OpenMode.CREATE_OR_APPEND;
}
public string FieldName { get; }
public int MaxResults { get; set; }
public void Add(string term)
{
using (var writer = new IndexWriter(Directory, WriterConfig))
{
IndexDoc(writer, term);
}
}
public void AddRange(string[] terms)
{
using (var writer = new IndexWriter(Directory, WriterConfig))
{
foreach (string term in terms)
{
IndexDoc(writer, term);
}
}
}
public string[] WhereStartsWith(string term)
{
using (var reader = DirectoryReader.Open(Directory))
{
IndexSearcher searcher = new IndexSearcher(reader);
var query = new PrefixQuery(new Term(FieldName, term));
TopDocs foundDocs = searcher.Search(query, MaxResults);
var matches = foundDocs.ScoreDocs
.Select(scoreDoc => searcher.Doc(scoreDoc.Doc).Get(FieldName))
.ToArray();
return matches;
}
}
public void Dispose()
{
Directory.Dispose();
Analyzer.Dispose();
}
}
}
运行此:
var indexValues = new string[] { "apple fruit", "appricot", "ape", "avacado", "banana", "pear" };
var index = new LuceneAutoCompleteIndex("fn", 10);
index.AddRange(indexValues);
var matches = index.WhereStartsWith("app");
foreach (var match in matches)
{
Console.WriteLine(match);
}
您得到了:
apple fruit
appricot