Now am doing analyzing on solr 4.1 version .In which,new Feature "SOLR-4271: Add support for PostingsHighlighter." has been given.
From the following link, http://lucene.apache.org/solr/4_1_0/solr-core/org/apache/solr/highlight/PostingsSolrHighlighter.html I found how to configure PostingHighlighter.
So I configured my PostingHighLighter as follows,
< searchComponent class="solr.HighlightComponent" name="highlight">
< highlighting class="org.apache.solr.highlight.PostingsSolrHighlighter"
preTag="<em_testing>"
postTag="</em_testing>"
ellipsis="... "
/>
< /searchComponent>
I used the following query to test highlighter;
solr/collection1/query?q=electronics&shard.keys=customerB!&wt=xml&hl=true&hl.fl=cat
But my result was, following one < lst name="highlighting">
< lst name="F8V7067-APL-KIT">
< arr name="cat">
< str>
< em>electronics< /em>
< /str>
< /arr>
The expected result is < em_testing> instead of < em>.
So Whats wrong with my configuration or what is the actual use of PostingSolrHighlighter.