利用SOLR搭建企业搜索平台 之八（solr 实现去掉重复的搜索结果，打SOLR-236_collapsing.patch补丁）

引用Bory.Chanhttp://blog.chenlb.com/2009/04/apply-solr-collapsing-patch-remove-duplicate-result.html 
打上SOLR-236_collapsing.patch补丁，实现 solr 搜索结果折叠、除去重复的搜索结果，可以实现类似google搜索结果的“站内的其它相关信息 ”。solr collapsing patch 是用 hash 某个字段来实现折叠重复结果的。下面我演示下应用这个补丁并搜索试用下。 

其实 solr 上已经有了这功能的实现：solr 1.3 collapse patch， 请看：https://issues.apache.org/jira/browse/SOLR-236，我这里下载是了新的：https://issues.apache.org/jira/secure/attachment/12403590/SOLR-236_collapsing.patch。 

下载好后就需要打上补丁了，先准备一份源码在D:/apache-solr-1.3.0目录下。没有可以去下载：http://archive.apache.org/dist/lucene/solr/1.3.0/apache-solr-1.3.0.zip。把SOLR-236_collapsing.patch文件放在D:/apache-solr-1.3.0目录下， 打补丁有我知道的有两种：用linux工具 patch（windows 下有 cygwin）；用 ant 的 patch。 

windows cygwin 的 patch： 

D:\apache-solr-1.3.0>patch -p0 < SOLR-236_collapsing.patch
patching file src/test/org/apache/solr/search/TestDocSet.java
patching file src/java/org/apache/solr/search/CollapseFilter.java
patching file src/java/org/apache/solr/search/DocSet.java
patching file src/java/org/apache/solr/search/NegatedDocSet.java
patching file src/java/org/apache/solr/search/SolrIndexSearcher.java
patching file src/java/org/apache/solr/common/params/CollapseParams.java
patching file src/java/org/apache/solr/handler/component/CollapseComponent.java

ant patch，把下面的内容保存为 patch-build.xml 放到 D:\apache-solr-1.3.0 目录下： 

<?xml version="1.0" encoding="UTF-8"?>
<project name="solr-patch" default="apply-patch" basedir=".">

    <target name="apply-patch" description="Apply a patch file.  Set -Dpatch.file">
        <patch patchfile="${patch.file}" strip="0"/>
    </target>
</project>

  
ant 打补丁： 

D:\apache-solr-1.3.0>ant -Dpatch.file=SOLR-236_collapsing.patch -f patch-build.xml
Buildfile: patch-build.xml

apply-patch:
[patch] patching file src/test/org/apache/solr/search/TestDocSet.java
[patch] patching file src/java/org/apache/solr/search/CollapseFilter.java
[patch] patching file src/java/org/apache/solr/search/DocSet.java
[patch] patching file src/java/org/apache/solr/search/NegatedDocSet.java
[patch] patching file src/java/org/apache/solr/search/SolrIndexSearcher.java
[patch] patching file src/java/org/apache/solr/common/params/CollapseParams.java
[patch] patching file src/java/org/apache/solr/handler/component/CollapseComponent.java

BUILD SUCCESSFUL
Total time: 0 seconds

源码打上了补丁，然后用 ant 构建源码： 

D:\apache-solr-1.3.0>ant dist 

在 D:/apache-solr-1.3.0/dist 目录下可以找到编译好的 solr 了。然后把 solr 放到 tomcat 中去运行它，把下面的内容保存在 TOMCAT_HOME/conf/Catalina/localhost/solr.xml 文件中： 

<Context docBase="D:\apache-solr-1.3.0\dist\apache-solr-1.3.0.war" reloadable="true" >
    <Environment name="solr/home" type="java.lang.String" value="D:\apache-solr-1.3.0\example\solr" override="true" />
</Context>

修改 D:\apache-solr-1.3.0\example\solr\conf\solrconfig.xml 使 solr 可以支持 collapse。 

定义搜索组件，在 QueryComponent 附近： 

<searchComponent name="collapse" class="org.apache.solr.handler.component.CollapseComponent" />  
定义一个 handler 使用上面的搜索组件： 

<requestHandler name="collapse" class="solr.SearchHandler">
  <!-- default values for query parameters -->
   <lst name="defaults">
     <str name="echoParams">explicit</str>
   </lst>
  <arr name="components">
    <str>collapse</str>
    <str>debug</str>
  </arr>
</requestHandler>

安装启动 tomcat，现在提交一些数据给它，用官方的示例数据就可以了。运行： 

D:\apache-solr-1.3.0\example\exampledocs>java -Durl=http://localhost:8080/solr/update -Dcommit=yes -jar post.jar *.xml
SimplePostTool: version 1.2
SimplePostTool: WARNING: Make sure your XML documents are encoded in UTF-8, other encodings are not currently supported
SimplePostTool: POSTing files to http://localhost:8080/solr/update..
SimplePostTool: POSTing file hd.xml
SimplePostTool: POSTing file ipod_other.xml
SimplePostTool: POSTing file ipod_video.xml
SimplePostTool: POSTing file mem.xml
SimplePostTool: POSTing file monitor.xml
SimplePostTool: POSTing file monitor2.xml
SimplePostTool: POSTing file mp500.xml
SimplePostTool: POSTing file sd500.xml
SimplePostTool: POSTing file solr.xml
SimplePostTool: POSTing file spellchecker.xml
SimplePostTool: POSTing file utf8-example.xml
SimplePostTool: POSTing file vidcard.xml
SimplePostTool: COMMITting Solr index changes..

http://localhost:8080/solr/admin/stats.jsp 有结果了？ 有了。然后开始查询试试看。 

查询：http://localhost:8080/solr/select/?q=*%3A*&indent=on&qt=collapse&collapse=true&collapse.field=popularity&collapse.threshold=1 

结果： 

<?xml version="1.0" encoding="UTF-8"?>
<response>

<lst name="responseHeader">
 <int name="status">0</int>
 <int name="QTime">0</int>
 <lst name="params">
  <str name="collapse.field">popularity</str>
  <str name="fl">id</str>
  <str name="collapse.threshold">1</str>
  <str name="indent">on</str>
  <str name="q">*:*</str>
  <str name="qt">collapse</str>
  <str name="collapse">true</str>
 </lst>
</lst>
<lst name="collapse_counts">
 <str name="field">popularity</str>
 <lst name="doc">
  <int name="SP2514N">4</int>
  <int name="F8V7067-APL-KIT">1</int>
  <int name="MA147LL/A">1</int>
  <int name="TWINX2048-3200PRO">1</int>
  <int name="VS1GB400C3">3</int>
  <int name="1">10</int>
 </lst>
 <lst name="count">
  <int name="6">4</int>
  <int name="1">1</int>
  <int name="10">1</int>
  <int name="5">1</int>
  <int name="7">3</int>
  <int name="0">10</int>
 </lst>
 <str name="debug">HashDocSet(6) Time(ms): 0/0/0/0</str>
</lst>
<result name="response" numFound="6" start="0">
 <doc>
  <str name="id">SP2514N</str>
 </doc>
 <doc>
  <str name="id">F8V7067-APL-KIT</str>
 </doc>
 <doc>
  <str name="id">MA147LL/A</str>
 </doc>
 <doc>
  <str name="id">TWINX2048-3200PRO</str>
 </doc>
 <doc>
  <str name="id">VS1GB400C3</str>
 </doc>
 <doc>
  <str name="id">1</str>
 </doc>
</result>
</response>
可以看到 collapse_counts 相关的输出：

<lst name="collapse_counts">
 <str name="field">popularity</str>
 <lst name="doc">
  <int name="SP2514N">4</int>
...
 </lst>
 <lst name="count">
  <int name="6">4</int>
  <int name="1">1</int>
  <int name="10">1</int>
  <int name="5">1</int>
  <int name="7">3</int>
  <int name="0">10</int>
 </lst>
 <str name="debug">HashDocSet(6) Time(ms): 0/0/0/0</str>
</lst>

上面的 count 下的内容（它的顺序是result/doc的顺序），表示 popularity=6 相同的结果还有 4 个，与 popularity=1 相同的结果还有 1 个，依此类推。这样就可以显示给用户的界面里提示“相同的其它内容不有N个”。 

使用的参数有： 

#启用 collapse 组件  
collapse=true  
#用那个字段来 hash 去除重量内容  
collapse.field=popularity  
#要结果中可以最多出现几个相同的文档  
collapse.threshold=1  
当然还有其它参数，请看：org.apache.solr.common.params.CollapseParams 类。