solr拼写检查(spellCheck)

xuyaxiu

　　拼写检查(spellCheck)
　　首先配置 solrconfig.xml，文件可能已经有这两个元素(如果没有添加即可)，需要根据我们自己的系统环境做些适当的修改。

  <searchComponent name="spellcheck" class="solr.SpellCheckComponent">
<lst name="spellchecker">
<str name="name">default</str>
<!--这里指明需要根据哪个字段的索引为依据进行拼写检查。现配置 名为 name 的字段-->
<str name="field">name</str>
<!--拼写检查索引的目录-->
<str name="spellcheckIndexDir">spellchecker</str>
<!--当commit的时候，对拼写检查索引进行构建。(只有构建后，拼写检查才有效果)-->
<!--当然，也可以选择在optimize的时候，进行构建。那么只需要将"buildOnCommint"换为 "buildOnOptimize"-->
<str name="buildOnCommit">true</str>
</lst>
</searchComponent>
<requestHandler name="/spell" class="solr.SearchHandler" startup="lazy">
<!--默认参数-->
<lst name="defaults">
<str name="spellcheck.onlyMorePopular">false</str>
<str name="spellcheck.extendedResults">false</str>
<!--配置拼写检查提示结果的个数(可以根据需要适当加大)-->
<str name="spellcheck.count">1</str>
</lst>
<arr name="last-components">
<str>spellcheck</str>
</arr>
</requestHandler>

　　配置完之后，需要重新建遍索引才能有效。然后我们这以请求 http://localhost:8080/solr/spell?q=name:王麻字&spellcheck=true
 查询如果如下:

<?xml version="1.0" encoding="UTF-8"?>
<response>
<lst name="responseHeader">
<int name="status">0</int>
<int name="QTime">0</int>
</lst>
<result name="response" numFound="0" start="0"/>
<lst name="spellcheck">
<lst name="suggestions">
<lst name="王麻字">
<int name="numFound">1</int>
<int name="startOffset">0</int>
<int name="endOffset">3</int>
<arr name="suggestion">
<str>王麻子</str>
</arr>
</lst>
</lst>
</lst>
</response>
　　有时候我们需要以多个字段为依据进行拼写检查，但上面的配置只能设一个字段。为了达到同样的效果，
我能只能另行其道了。需要用到 coptyField 技术。比如我们在 schema.xml 中定义了

<field name="a" .../>
<field name="b" .../>
<field name="ab" multiValued="true" .../>
<copyField source="a" dest="ab" />
<copyField source="b" dest="ab" />
　　
然后配置 SpellCheckComponent 的字段为 ab 即可。
　　
要作用Solr的SpellCheck功能，需要以下配置：
1. 在solrConfig.xml最后加入以下片段：

<!-- spell -->
<searchComponent name="spellcheck" class="org.apache.solr.handler.component.SpellCheckComponent">

<lst name="spellchecker">
<!--
Optional, it is required when more than one spellchecker is configured.
Select non-default name with spellcheck.dictionary in request handler.
name是可选的，如果只有一个spellchecker可以不写name
如果有多个spellchecker，需要在Request Handler中指定spellcheck.dictionary
-->
<str name="name">default</str>
<!-- The classname is optional, defaults to IndexBasedSpellChecker -->
<str name="classname">solr.IndexBasedSpellChecker</str>
<!--
Load tokens from the following field for spell checking,
analyzer for the field's type as defined in schema.xml are used
下面这个field名字指的是拼写检查的依据，也就是说要根据哪个Field来检查用户输入。
-->
<str name="field">name_t</str>
<!-- Optional, by default use in-memory index (RAMDirectory)
SpellCheck索引文件的存放位置，是可选的，如果不写默认使用内存模式RAMDirectory。
./spellchecker1指的是：corex\data\spellchecker1
-->
<str name="spellcheckIndexDir">./spellchecker1</str>
<!-- Set the accuracy (float) to be used for the suggestions. Default is 0.5 -->
<str name="accuracy">0.7</str>
<!--何时创建拼写索引：buildOnCommit/buildOnOptimize -->
<str name="buildOnCommit">true</str>
</lst>
<!-- 另一个拼写检查器，使用JaroWinklerDistance距离算法 -->
<lst name="spellchecker">
<str name="name">jarowinkler</str>
<str name="classname">solr.IndexBasedSpellChecker</str>
<str name="field">name_t</str>
<!-- Use a different Distance Measure -->
<str name="distanceMeasure">org.apache.lucene.search.spell.JaroWinklerDistance</str>
<str name="spellcheckIndexDir">./spellchecker2</str>
<str name="buildOnCommit">true</str>
</lst>
<!-- 另一个拼写检查器，使用文件内容为检查依据 -->
<lst name="spellchecker">
<str name="classname">solr.FileBasedSpellChecker</str>
<str name="name">file</str>
<str name="sourceLocation">spellings.txt</str>
<str name="characterEncoding">UTF-8</str>
<str name="spellcheckIndexDir">./spellcheckerFile</str>
<str name="buildOnCommit">true</str>
</lst>
<!-- This field type's analyzer is used by the QueryConverter to tokenize the value for "q" parameter
-->
<str name="queryAnalyzerFieldType">text</str>

</searchComponent>
<!--
The SpellingQueryConverter to convert raw (CommonParams.Q) queries into tokens.  Uses a simple regular expression
to strip off field markup, boosts, ranges, etc. but it is not guaranteed to match an exact parse from the query parser.

Optional, defaults to solr.SpellingQueryConverter
-->
<queryConverter name="queryConverter" class="solr.SpellingQueryConverter"/>

<!--  Add to a RequestHandler
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
NOTE:  YOU LIKELY DO NOT WANT A SEPARATE REQUEST HANDLER FOR THIS COMPONENT.  THIS IS DONE HERE SOLELY FOR
THE SIMPLICITY OF THE EXAMPLE.  YOU WILL LIKELY WANT TO BIND THE COMPONENT TO THE /select STANDARD REQUEST HANDLER.
下面这个Handler不是必需的，写在这里只是一个简单的例子，可以把相应的设置放到Standard request handler中就可以。
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
-->
<requestHandler name="/spell" class="solr.SearchHandler">
<lst name="defaults">
<!-- Optional, must match spell checker's name as defined above, defaults to "default" -->
<str name="spellcheck.dictionary">file</str>
<!-- omp = Only More Popular -->
<str name="spellcheck.onlyMorePopular">true</str>
<!-- exr = Extended Results -->
<str name="spellcheck.extendedResults">true</str>
<!--  The number of suggestions to return -->
<str name="spellcheck.count">1</str>
</lst>
<!--  Add to a RequestHandler
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
REPEAT NOTE:  YOU LIKELY DO NOT WANT A SEPARATE REQUEST HANDLER FOR THIS COMPONENT.  THIS IS DONE HERE SOLELY FOR
THE SIMPLICITY OF THE EXAMPLE.  YOU WILL LIKELY WANT TO BIND THE COMPONENT TO THE /select STANDARD REQUEST HANDLER.
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
-->
<arr name="last-components">
<str>spellcheck</str>
</arr>
</requestHandler>

　　
2. 如果使用File的方式，需要在spell.txt中加入相应的拼写建议，每个拼写建议占一行。
　　3. 配置文件修改完后，需要重做索引，这样会在索引目录里出现下面的目录
　　
分别对应拼写组件中每个SpellChecker对应的索引文件。
　　4. 在需要拼写检查的页面加入如下方法：

/**
*
* get spell suggestion from core
*
*
* @param keyword
* @param coreName
* @return
* @throws Exception
*/
private Collection<String> getSpellCheckFromCore(String keyword,String coreName) throws Exception {
Collection<String> suggestion = new ArrayList<String>();
CoreContainer container = SearchManager.getCoreContainer();
SolrCore core = container.getCore(coreName);
SearchComponent speller = core.getSearchComponent("spellcheck");

ModifiableSolrParams params = new ModifiableSolrParams();
params.add(CommonParams.QT, "/spell");
params.add(SpellCheckComponent.SPELLCHECK_BUILD, "true");
params.add(CommonParams.Q, keyword);
params.add(SpellCheckComponent.COMPONENT_NAME, "true");
params.add(SpellCheckComponent.SPELLCHECK_COLLATE, "true");

SolrRequestHandler handler = core.getRequestHandler("/spell");
SolrQueryResponse rsp = new SolrQueryResponse();
rsp.add("responseHeader", new SimpleOrderedMap());
handler.handleRequest(new LocalSolrQueryRequest(core, params), rsp);
NamedList values = rsp.getValues();
NamedList spellCheck = (NamedList) values.get("spellcheck");
NamedList suggestions = (NamedList) spellCheck.get("suggestions");
Boolean correctlySpelled = (Boolean) suggestions.get("correctlySpelled");
if(correctlySpelled == null){
String collation = (String) suggestions.get("collation");
suggestion.add(collation);
}

return suggestion;
}

　　可以把返回的结果直接显示到页面相应的地方。