我想在名为"a“和"b”的两个字段上搜索我的索引。我得到了像Freud -- theories of psychology
这样的搜索,我想执行以下查询:
(a="Freud" AND b="theories of psychology") OR (b="Freud" AND a="theories of psychology")
我该怎么做呢?到目前为止,我让Lucene使用MultiFieldQueryParser
构建了两个部分(firstHalf
和secondHalf
),然后我将它们与
BooleanQuery combined = new BooleanQuery();
combined.add(firstHalf, BooleanClause.Occur.SHOULD);
combined.add(secondHalf, BooleanClause.Occur.SHOULD);
但是combined
允许在只找到“理论”而不是“心理学”的地方返回结果,而我肯定想要这两个词。看起来Lucene正在将“心理学理论”分成三个单词,并将它们分别与OR组合在一起。我如何防止这种情况发生?
firstHalf
看起来像这样:
Query firstHalf = MultiFieldQueryParser.parse(Version.LUCENE_33,
new String[]{"Freud", "theories of psychology"},
new String[]{"a", "b"},
new BooleanClause.Occur[]{BooleanClause.Occur.MUST, BooleanClause.Occur.MUST},
analyzer);
其中analyzer
只是一个StandardAnalyzer
对象。
发布于 2011-11-29 04:10:30
我自己想出来了,但现在代码明显变长了;如果有人知道更优雅的解决方案,请张贴,我很乐意奖励。:) (尽管我将把它变成一个方法shortly...but,但这里是所发生的事情的完整版本...)
QueryParser parser = new QueryParser(Version.LUCENE_33, "a", analyzer);
parser.setDefaultOperator(QueryParser.AND_OPERATOR);
Query a_0 = parser.parse("Freud");
parser = new QueryParser(Version.LUCENE_33, "b", analyzer);
parser.setDefaultOperator(QueryParser.AND_OPERATOR);
Query b_1 = parser.parse("theories of psychology");
BooleanQuery firstHalf = new BooleanQuery();
firstHalf.add(a_0, BooleanClause.Occur.MUST);
firstHalf.add(b_1, BooleanClause.Occur.MUST);
parser = new QueryParser(Version.LUCENE_33, "b", analyzer);
parser.setDefaultOperator(QueryParser.AND_OPERATOR);
Query b_0 = parser.parse("Freud");
parser = new QueryParser(Version.LUCENE_33, "a", analyzer);
parser.setDefaultOperator(QueryParser.AND_OPERATOR);
Query a_1 = parser.parse("theories of psychology");
BooleanQuery secondHalf = new BooleanQuery();
secondHalf.add(b_0, BooleanClause.Occur.MUST);
secondHalf.add(a_1, BooleanClause.Occur.MUST);
BooleanQuery combined = new BooleanQuery();
combined.add(firstHalf, BooleanClause.Occur.SHOULD);
combined.add(secondHalf, BooleanClause.Occur.SHOULD);
事实证明,SHOULD
确实按照我需要的方式在这里工作。希望有人发现这对我有帮助,我不仅仅是在公共场合自言自语;)
发布于 2011-11-24 06:13:14
标准分析器将进行标记化。因此,查询theories of psychology
等同于theories OR of OR psychology
。
如果你想搜索短语“心理学理论”,使用PhraseQuery,或者注意默认的QueryParser会将引号解释为一个短语的意思(例如,将你的代码改为"\"theories of psychology\""
)。
是的,Lucene在某种意义上没有使用布尔逻辑,但它是技术上的,在这里并不是真正相关。
发布于 2013-05-30 17:34:53
我写了下面的类来生成链式模糊查询,其中一个术语必须在多个字段中进行搜索。可以通过调用GetQuery()
方法来检索组合查询。
public class QueryParam
{
public string[] Fields { get; set; }
public string Term { get; set; }
private QueryParam _andOperandSuffix;
private QueryParam _orOperandSuffix;
private readonly BooleanQuery _indexerQuery = new BooleanQuery();
public QueryParam(string term, params string[] fields)
{
Term = term;
Fields = fields;
}
public QueryParam And(QueryParam queryParam)
{
_andOperandSuffix = queryParam;
return this;
}
public QueryParam Or(QueryParam queryParam)
{
_orOperandSuffix = queryParam;
return this;
}
public BooleanQuery GetQuery()
{
foreach (var field in Fields)
_indexerQuery.Add(new FuzzyQuery(new Term(field, Term)), Occur.SHOULD);
if (_andOperandSuffix != null)
_indexerQuery.Add(_andOperandSuffix.GetQuery(),Occur.MUST);
if (_orOperandSuffix != null)
_indexerQuery.Add(_orOperandSuffix.GetQuery(), Occur.SHOULD);
return _indexerQuery;
}
}
示例:
var leftquery = new QueryParam("Freud", "a").And(new QueryParam("theories of psychology", "b"));
var rightquery = new QueryParam("Freud", "b").And(new QueryParam("theories of psychology", "a"));
var query = leftquery.Or(rightquery);
https://stackoverflow.com/questions/8246790
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