how to convert json string to dataframe on spark

Question

I want to convert string variable below to dataframe on spark.

val jsonStr = \"{ \"metadata\": { \"key\": 84896, \"value\": 54 }}\"

I know

Answer 1

simple_json = '{"results":[{"a":1,"b":2,"c":"name"},{"a":2,"b":5,"c":"foo"}]}'
rddjson = sc.parallelize([simple_json])
df = sqlContext.read.json(rddjson)

The reference to the answer is https://stackoverflow.com/a/49399359/2187751