Sending XML to JAVA - Angular 2

Question

Guys, I’m trying to send an XML from my Angular 2 view to a Java backend. In java I have a Servlet that searches the xml for the parameter:

request.getParameter("xml")

And in my angular service I’m doing it this way:

let urlSearchParams = new URLSearchParams();

urlSearchParams.append('xml', params);

let body = urlSearchParams.toString();

return this._http.post(url, body).map(this.extractJson);

Where the params is xml, which comes as a function parameter. The URL is correct, debugging Java I get the request but the parameter is null. Something wrong that I’m doing?