One of our project, we have to get the data from Cassandra tables and populate it in JSON format in response. What are the possible ways to do it for the same? Some time, we require to get the data from more than one Cassandra table. What are possible ways available for the same especially what are the ways to connect Cassandra?
You can query your data and retrieve a JSON string with the following type of queries:
SELECT JSON keyspace_name, durable_writes FROM system_schema.keyspaces ;
This will return you a json string that maps the keys (column name) with the corresponding value. See the doc here: http://cassandra.apache.org/doc/latest/cql/json.html
Then you could re-insert the json string in Cassandra, if that's what you want.
If you need to do that at scale, or as a streaming job, you would want to look at using Spark on top of Cassandra: Load your Cassandra data into spark, use spark to transform that into a JSON string, and reinsert into Cassandra or another db.