title: Stream reading from database using spark streaming
body: <p>I want to use spark streaming to read data from RDBMS database like mysql.</p>
  
  <p>but I don't know how to do this using JavaStreamingContext</p>
  
  <pre><code> JavaStreamingContext jssc = new JavaStreamingContext(conf, Durations.milliseconds(500));
  DataFrame df = jssc. ??
  </code></pre>
  
  <p>I search in the internet but I didn't find anything</p>
  
  <p>thank you in advance.</p>