Indexing JSON in Solr 3.1
Lucid Imagination ยป Indexing JSON in Solr 3.1
Solr has been able to produce JSON results for a long time, by adding wt=json to any query. A new capability has recently been added to allow indexing in JSON, as well as issuing other update commands such as deletes and commits.

All of the functionality that was available through XML update commands can now be given in JSON.