Using the @RequestMapping annotation, it is straightforward to define REST APIs using a richer set of HTTP methods to specify the semantics of each operation, for example GET, POST, PUT, and DELETE.

To maintain compatibility with clients which support only GET and POST such as older browsers, Spring provides a filter org.springframework.web.filter.HiddenHttpMethodFilter to effectively tunnel any HTTP method through a POST request. If you intend to make use of HTTP methods other than GET and POST in your handler mappings, add this filter to your CAE web application's web.xml or web-fragment.xml:

<filter>
  <filter-name>HTTP Method Filter</filter-name>
  <filter-class>
    org.springframework.web.filter.HiddenHttpMethodFilter
  </filter-class>
</filter>

<filter-mapping>
  <filter-name>HTTP Method Filter</filter-name>
  <url-pattern>/*</url-pattern>
</filter-mapping>

With this filter in place, to signal the use of a particular HTTP method from the client, you may send a POST request with an additional parameter indicating the HTTP method to use. By default, the filter expects a parameter named _method. Note that only POST requests will be handled by this filter.

<form action="${url}" method="POST">
  <input type="hidden" name="_method" value="PUT"/>

  ...
</form>

Of course, clients supporting the HTTP method PUT, may send a PUT request directly, without adding the _method parameter.