Solrj Api Use in Java code - solr

Question

Anybody pleasee help.I am new to Solr.My project uses Solrj api to access solr in java code.I don't understand the different steps in querying with solr and solrj.I got ths following code from net.Can anyone please describe the importance of these statements.?
public class SolrJSearcher {
public static void main(String[] args) throws MalformedURLException, SolrServerException {
HttpSolrServer solr = new HttpSolrServer("http://localhost:8983/solr");
SolrQuery query = new SolrQuery();
query.setQuery("sony digital camera");
query.addFilterQuery("cat:electronics","store:amazon.com");
query.setFields("id","price","merchant","cat","store");
query.setStart(0);
query.set("defType", "edismax");
QueryResponse response = solr.query(query);
SolrDocumentList results = response.getResults();
for (int i = 0; i < results.size(); ++i) {
System.out.println(results.get(i));
}
}
}

Answer 1

You'll have to read up on Solr concepts to actually use SolrJ for anything useful, so that you're able to tell what the different parts of the API are. I'm not going to go into any detail here, and you should really research a concept more before posting a very broad and basic question. I'll answer it for further reference for anyone stumbling across this post from the Internet anyway, or if anyone need to reference it from another post.
setQuery - The actual query to send to Solr. This is what usually goes in the q parameter when reading the Solr documentation. The format of the query depends on which query parser you're using (which is edismax here, I'll get back to that). Lucene query syntax in general is field:value.
addFilterQuery - Filter the search result by the values supplied. This is what you'll see in the fq parameter in the Solr docs. A filter query doesn't affect scoring, it just filters the search result returned by Solr by removing any documents that doesn't match the filter query.
setFields - Which fields to return from the index. If you don't need all the fields, you can cut down the size of the response from Solr by just requesting the fields you need.
setStart - The offset of the query result, which document hit to start retrieving data from. Useful for pagination.
set - Set any parameter that isn't available through dedicated methods. Here the parameter defType is set, which tells Solr which query parser to use. edismax is one such query parser, that accepts queries in a natural format like you'd expect most people to be familiar with from general search engines.
query - Performs the actual query on the Solr server, and retrieves the result. The response is returned, and then used to get the list of documents in the result (getResults ).
The results are then printed out one by one.