如何用SolrJ索引pdf的内容？

import static org.apache.solr.handler.extraction.ExtractingParams.LITERALS_PREFIX;
import static org.apache.solr.handler.extraction.ExtractingParams.MAP_PREFIX;
import static org.apache.solr.handler.extraction.ExtractingParams.UNKNOWN_FIELD_PREFIX;

import org.apache.solr.client.solrj.SolrServer;
import org.apache.solr.client.solrj.SolrServerException;
import org.apache.solr.client.solrj.impl.CommonsHttpSolrServer;
import org.apache.solr.client.solrj.request.AbstractUpdateRequest;
import org.apache.solr.client.solrj.request.ContentStreamUpdateRequest;
import org.apache.solr.common.util.NamedList;
...
public static void indexFilesSolrCell(String fileName) throws IOException, SolrServerException {

  String urlString = \"http://localhost:8080/solr\"; 
  SolrServer server = new CommonsHttpSolrServer(urlString);

  ContentStreamUpdateRequest up = new ContentStreamUpdateRequest(\"/update/extract\");
  up.addFile(new File(fileName));
  String id = fileName.substring(fileName.lastIndexOf(\'/\')+1);
  System.out.println(id);

  up.setParam(LITERALS_PREFIX + \"id\", id);
  up.setParam(LITERALS_PREFIX + \"location\", fileName); // this field doesn\'t exists in schema.xml, it\'ll be created as attr_location
  up.setParam(UNKNOWN_FIELD_PREFIX, \"attr_\");
  up.setParam(MAP_PREFIX + \"content\", \"attr_content\");
  up.setAction(AbstractUpdateRequest.ACTION.COMMIT, true, true);

  NamedList<Object> request = server.request(up);
  for(Entry<String, Object> entry : request){
    System.out.println(entry.getKey());
    System.out.println(entry.getValue());
  }
}

<doc>
  <arr name=\"attr_content\">
    <str>            </str>
  </arr>
  <arr name=\"attr_location\">
    <str>/home/alex/Documents/lsp.pdf</str>
  </arr>
  <arr name=\"attr_meta\">
    <str>stream_size</str>
    <str>31203</str>
    <str>Content-Type</str>
    <str>application/pdf</str>
  </arr>
  <arr name=\"attr_stream_size\">
    <str>31203</str>
  </arr>
  <arr name=\"content_type\">
    <str>application/pdf</str>
  </arr>
  <str name=\"id\">lsp.pdf</str>
</doc>