title: How to insert a map<Integer, String> as @RequestParam with Postman
body: <p>first of all, sorry for my english, it's not my main language, and I'm not sure the question is fully understandable.</p>
  
  <p>I need to do some queries after receiving a Map as a @RequestParam of a Rest Web Service.</p>
  
  <p>I'm trying to call the web service with Postman, and here is the full POST request
      <a href="http://localhost:8080/CDRestApi/rest/cd/esibizione/getIdUdFromIstanzaMetadatoByMap/5/map?25=ALAN&amp;26=IANESELLI" rel="nofollow noreferrer">http://localhost:8080/CDRestApi/rest/cd/esibizione/getIdUdFromIstanzaMetadatoByMap/5/map?25=ALAN&amp;26=IANESELLI</a></p>
  
  <p>This is my WS code:</p>
  
  <pre><code>    @RequestMapping(value = { "/getIdUdFromIstanzaMetadatoByMap/{id}/map" }, method = RequestMethod.POST, produces = {
          MediaType.APPLICATION_JSON_VALUE })
  @ResponseBody
  public String selectIstanzaMetadato(@PathVariable Long id,
                                      @RequestParam (value="map", required=true) Map&lt;Integer,String&gt; mapQuery) {
  
      Integer key = 25;
      System.out.println(mapQuery.get(key));
      return mapQuery.get(key).toString();
  }
  </code></pre>
  
  <p>And this is the postman answer:</p>
  
  <pre><code>{
  "timestamp": 1505834218902,
  "status": 500,
  "error": "Internal Server Error",
  "exception": "java.lang.NullPointerException",
  "message": "No message available",
  "path": "/CDRestApi/rest/cd/esibizione/getIdUdFromIstanzaMetadatoByMap/5/map"
  </code></pre>
  
  <p>}</p>
  
  <p>the System.out print is:</p>
  
  <pre><code>17:16:58,891 INFO  [stdout] (default task-4) null
  </code></pre>
  
  <p>I suppose the mapQuery object has no value, because it is not correctly valorized</p>
  
  <p>I have already seen those posts, but they were not useful to me:
  <a href="https://stackoverflow.com/questions/22916923/mapstring-string-as-requestparam-in-spring-mvc">Map&lt;String, String&gt; as @RequestParam in Spring MVC</a> 
  and 
  <a href="https://stackoverflow.com/questions/16355168/spring-mvc-requestparam-as-map-get-url-array-parameters-not-working">Spring MVC + RequestParam as Map + get URL array parameters not working</a> </p>
  
  <p>Do I miss the correct Postman POST request ? or it is a problem of the webservice itself ?</p>