title: Spring Rest Controller find by id/ids methods
body: <p>I have the following method in my Spring RestController:</p>
  
  <pre><code>@RequestMapping(value = "/{decisionId}", method = RequestMethod.GET)
      public DecisionResponse findById(@PathVariable @NotNull @DecimalMin("0") Long decisionId) {
  ....
  }
  </code></pre>
  
  <p>Right now I need to add the possibility to find a set of DecisionResponse  by <code>{decisionIds}</code>.. something like this:</p>
  
  <pre><code>@RequestMapping(value = "/{decisionIds}", method = RequestMethod.GET)
      public List&lt;DecisionResponse&gt; findByIds(@PathVariable @NotNull @DecimalMin("0") Set&lt;Long&gt; decisionIds) {
  ....
  }
  </code></pre>
  
  <p>The following two methods don't work together.</p>
  
  <p>What is a correct way of implementing this functionality? Should I leave only one method(second) that waits for <code>{decisionIds}</code> and returns a collection even when I need only 1 <code>Decision</code> object? Is there another proper way to implement this?</p>