how to convert json string to dataframe on spark
<p>I want to convert string variable below to dataframe on spark.</p>

<pre><code>val jsonStr = "{ "metadata": { "key": 84896, "value": 54 }}"
</code></pre>

<p>I know how to create dataframe from json file. </p>

<pre><code>sqlContext.read.json("file.json")
</code></pre>

<p>but I don't know how to create dataframe from string variable.</p>

<p>How can I convert json String variable to dataframe.</p>