title: Spring Cloud Feign Client @RequestParam with List parameter creates a wrong request
body: <p>I have a Spring Clound Feign Client mapping defined as following</p>
  
  <pre><code>@RequestMapping(method = RequestMethod.GET, value = "/search/findByIdIn")
  Resources&lt;MyClass&gt; get(@RequestParam("ids") List&lt;Long&gt; ids);
  </code></pre>
  
  <p>when I call</p>
  
  <pre><code>feignClient.get(Arrays.asList(1L,2L,3L))
  </code></pre>
  
  <p>according to what I can see in the debugger, the feign-core library forms the following request:</p>
  
  <pre><code>/search/findByIdIn?ids=1&amp;ids=2&amp;ids=3
  </code></pre>
  
  <p>instead of expected</p>
  
  <pre><code>/search/findByIdIn?ids=1,2,3
  </code></pre>
  
  <p>which would be correct for the server Spring Data REST endpoint declared in the same way as my Feign client method.</p>
  
  <p>Thus, because of this issue, the request always returns empty set.</p>
  
  <p>I have seen similar <a href="https://stackoverflow.com/questions/32098906/spring-cloud-feign-client-duplicate-list-values">question</a>, but it looks like the Feign client was working as I expect back in 2015.</p>
  
  <p>I am using:</p>
  
  <ul>
  <li>spring-cloud-starter-feign version 1.2.4.RELEASE</li>
  <li>feign-httpclient version 9.4.0</li>
  <li>feign-core version 9.4.0</li>
  </ul>
  
  <p>Is there a way to correct the behaviour and "marry" the Spring Cloud Feign Client with the Spring Data REST defined endpoints?</p>