Add auto generated field to Solr 4

11.       Define new type :

fieldType name="uuid" class="solr.UUIDField" indexed="true" />

22.       Add new field

<field name="rami" type="uuid" indexed="true" stored="true" default="NEW"/>

(parameter – default-“NEW” does the trick!)

33.                       <updateRequestProcessorChain name="uuid">

<processor class="solr.UUIDUpdateProcessorFactory">

<str name="fieldName">rami</str>

</processor>

<processor class="solr.RunUpdateProcessorFactory" />

</updateRequestProcessorChain>

44.       To the relevant handler add the chain

Example: for /update/extract

  <requestHandler name="/update/extract"

                  startup="lazy"

                  class="solr.extraction.ExtractingRequestHandler" >

    <lst name="defaults">

      <str name="lowernames">true</str>

      <str name="uprefix">ignored_</str>

      <!-- capture link hrefs but ignore div attributes -->

      <str name="captureAttr">true</str>

      <str name="fmap.a">links</str>

      <str name="fmap.div">ignored_</str>

                  <str name="update.chain">uuid</str>

    </lst>

  </requestHandler>

Now u can executer / update/extract without passing filed “rami” and it will be automatically generated.