One more suggestion. Some of the REST API's endpoints support the Graph Store Protocol and the SPARQL Protocol. You can send turtle to the graph store protocol with any HTTP client... here's the curl for it:
curl -Hcontent-type:text/turtle \ -d@'nameofturtlefile.ttl' \ -X PUT URLFORHOST/v1/graphs?graph=nameofgraph.
That endpoint takes care of the translation to sem:triple elements; you should never have to see that XML representation of triples.
Translate the curl call to Apache HTTP Client and you have a way to ingest turtle. I've also used the Jena API (look up riot) to save turtle to MarkLogic.