title: How to create multiple cache key in @Cacheable when parameter value is null
body: <p>I am trying to create a cache key with multiple parameter values.</p>
  
  <pre><code>@Cacheable(cacheNames = "cache_name_", key = "#name + '_' + #id")
  private JSONObject getData(String name, String id) throws Exception {
  </code></pre>
  
  <p>From the above scenario, I name is a mandatory field while id is optional. I want to create key in such a way that,</p>
  
  <ol>
  <li>If name = "test" and id = null, cache key must be cache_name_test</li>
  <li>If name = "test" and id = "2", cache key must be cache_name_test_2</li>
  </ol>
  
  <p>Currently, the key is forming something like "cache_name_test_null" if the id is not passed in the parameter value</p>
  
  <p>Is it possible to create such key with @Cacheable annotation?</p>