Lucene：不首先显示完全匹配

Question

我正在使用演示 IndexFiles 和 SearchFiles 类来索引和搜索 org.apache.lucene.demo 数据包中的内容。

我的问题是，当我使用包含多个单词的查询时，我没有得到完全匹配的结果。例如：

Enter query:
"natural language"
Searching for: "natural language"
298 total matching documents
1. download\researchers.uq.edu.au\fields-of-research\natural-language-processing
.txt
2. download\researchers.uq.edu.au\research-project\16267.txt
3. download\researchers.uq.edu.au\research-project\16279.txt
4. download\researchers.uq.edu.au\research-project\18361.txt
5. download\www.uq.edu.au\news\%3Farticle%3D2187.txt
6. download\researchers.uq.edu.au\researcher\2115.txt
7. download\ceit.uq.edu.au\content\2013-2014-summer-research-scholarship-project
s-dr-alan-cody%3Fpage%3D1.txt
8. download\ceit.uq.edu.au\content\2013-2014-summer-research-scholarship-project
s-dr-alan-cody%3Fpage%3D2.txt
9. download\ceit.uq.edu.au\content\2013-2014-summer-research-scholarship-project
s-dr-alan-cody.txt
10. download\www.ceit.uq.edu.au\content\2013-2014-summer-research-scholarship-pr
ojects-dr-alan-cody.txt
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与以下结果不同：

Enter query:
natural language
Searching for: natural language
54307 total matching documents
1. download\cyberschool.library.uq.edu.au\display_resource.phtml%3Frid%3D190.txt

2. download\cyberschool.library.uq.edu.au\display_resource.phtml%3Frid%3D576.txt

3. download\cyberschool.library.uq.edu.au\display_resource.phtml%3Frid%3D46.txt
4. download\espace.library.uq.edu.au\view\UQ%3A166163.txt
5. download\cyberschool.library.uq.edu.au\display_resource.phtml%3Frid%3D108.txt

6. download\cyberschool.library.uq.edu.au\display_resource.phtml%3Frid%3D70.txt
7. download\cyberschool.library.uq.edu.au\display_resource.phtml%3Frid%3D708.txt

8. download\researchers.uq.edu.au\fields-of-research\natural-language-processing
.txt
9. download\researchers.uq.edu.au\research-project\16267.txt
10. download\cyberschool.library.uq.edu.au\display_resource.phtml%3Frid%3D117.tx
t
Press (n)ext page, (q)uit or enter number to jump to a page.

例如第一个匹配的文档甚至不包含“语言”关键字。

如果我在IndexSearcher 类中使用explain() 方法，那么我将得到第一个结果：

1. download\cyberschool.library.uq.edu.au\display_resource.phtml%3Frid%3D190.txt
0.70643383 = (MATCH) sum of:
  0.5590494 = (MATCH) weight(contents:natural in 62541) [DefaultSimilarity], result of:
    0.5590494 = score(doc=62541,freq=4.0 = termFreq=4.0
), product of:
      0.8091749 = queryWeight, product of:
        4.4216847 = idf(docFreq=13111, maxDocs=401502)
        0.18300149 = queryNorm
      0.6908882 = fieldWeight in 62541, product of:
        2.0 = tf(freq=4.0), with freq of:
          4.0 = termFreq=4.0
        4.4216847 = idf(docFreq=13111, maxDocs=401502)
        0.078125 = fieldNorm(doc=62541)
  0.1473844 = (MATCH) weight(contents:language in 62541) [DefaultSimilarity], result of:
    0.1473844 = score(doc=62541,freq=1.0 = termFreq=1.0
), product of:
      0.5875679 = queryWeight, product of:
        3.2107275 = idf(docFreq=44012, maxDocs=401502)
        0.18300149 = queryNorm
      0.25083807 = fieldWeight in 62541, product of:
        1.0 = tf(freq=1.0), with freq of:
          1.0 = termFreq=1.0
        3.2107275 = idf(docFreq=44012, maxDocs=401502)
        0.078125 = fieldNorm(doc=62541)

如果我点击下一步并找到这样的结果：

19. download\www.uq.edu.au\news\%3Farticle%3D2187.txt
0.47449595 = (MATCH) sum of:
  0.2795247 = (MATCH) weight(contents:natural in 35173) [DefaultSimilarity], result of:
    0.2795247 = score(doc=35173,freq=4.0 = termFreq=4.0
), product of:
      0.8091749 = queryWeight, product of:
        4.4216847 = idf(docFreq=13111, maxDocs=401502)
        0.18300149 = queryNorm
      0.3454441 = fieldWeight in 35173, product of:
        2.0 = tf(freq=4.0), with freq of:
          4.0 = termFreq=4.0
        4.4216847 = idf(docFreq=13111, maxDocs=401502)
        0.0390625 = fieldNorm(doc=35173)
  0.19497125 = (MATCH) weight(contents:language in 35173) [DefaultSimilarity], result of:
    0.19497125 = score(doc=35173,freq=7.0 = termFreq=7.0
), product of:
      0.5875679 = queryWeight, product of:
        3.2107275 = idf(docFreq=44012, maxDocs=401502)
        0.18300149 = queryNorm
      0.33182758 = fieldWeight in 35173, product of:
        2.6457512 = tf(freq=7.0), with freq of:
          7.0 = termFreq=7.0
        3.2107275 = idf(docFreq=44012, maxDocs=401502)
        0.0390625 = fieldNorm(doc=35173)

哪个页面本身包含确切的关键字“自然语言”。所以我的问题是：

1) 为什么 Lucene 不首先显示完全匹配？

2) 为什么 Lucene 显示的结果甚至不包含关键字？

3) 我可以在哪里/如何更改它，以便它首先显示完全匹配的，然后显示更相关的？

Answer 1

1 - 不打算这样做。请参阅Lucene query syntax 上的文档。查询natural language 是由两个词组成的查询。就其本身而言，Lucene 并不倾向于将这些术语放在一起。如果你想找到完全匹配，短语查询是正确的方法，比如"natural language"

2 - 您包含解释的两个结果都包含两个术语的匹配项，请参阅：

0.2795247 = (MATCH) weight(contents:natural in 35173) [DefaultSimilarity], result of:
  0.2795247 = score(doc=35173,freq=4.0 = termFreq=4.0
...
0.19497125 = (MATCH) weight(contents:language in 35173) [DefaultSimilarity], result of:
  0.19497125 = score(doc=35173,freq=7.0 = termFreq=7.0

根据 Lucene，它在该文档中找到了 4 次“自然”一词，在内容字段（我假设这是您的默认字段）中找到了 7 次“语言”。

3 - 查看查询解析器语法，看看什么对您最有意义。听起来您可能会发现 Proximity Searches 很有用。

如果您只想简单地获得短语匹配，然后是其他人，您可以使用以下内容：

"natural language" natural language