title: how to get the row key from hbase scan result
body: <p>when scan the hbase table row by row, how can i get the row key? here is my code:</p>
  
  <pre><code>for (Result rr : scanner) {
     System.out.println(rr);
  }
  </code></pre>
  
  <p>is there any method like getKey() that i can use? thanks. </p>