title: Spring data mongodb Find by nested attribute in document
body: <p>Im using Spring data mongodb, and I was wondering how can I make a find using a nested attribute documents, using Repositories.
  Let´s imagine that I have this document:</p>
  
  <pre><code>{
      A:"val",
      B:{a:1, b:"test"},
      B:{a:1, b:"test"}
  }
  </code></pre>
  
  <p>And what I would like is make a find like <code>findByAa(int a);</code></p>
  
  <p>But that does not works, somebody can help me please!</p>
  
  <p>PS:I willing to not use mongoTemplate but repository.</p>
  
  <p>Thanks</p>