[OmniFaces utilities 2.0/2.2] Get the HTTP request query string as parameter values map

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[OmniFaces utilities] The getRequestQueryStringMap() method returns the HTTP request query string as parameter values map. Note this method returns only the request URL (GET) parameters, as opposed to HttpServletRequest#getParameterMap(), which contains both the request URL (GET) parameters and and the request body (POST) parameters.

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Method (starting with OmniFaces 2.2, this method become mutable):

See also: Utils#isEmpty() | Utils#decodeURL() | Servlets#getRequestQueryString()

Usage:

·         inside a servlet filter or even a plain vanilla servlet (basically, when FacesContext is not available):

import org.omnifaces.util.Servlets;

...

@WebServlet("/MyServlet")

public class MyServlet extends HttpServlet {

 protected void processRequest(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

  // e.g. request: http://localhost:8080/MyApp/MyServlet?tech=JSF&lib=OmniFaces&lib=PrimeFaces&type=utility&type=components

  // map content: {tech=[JSF], lib=[OmniFaces, PrimeFaces], type=[utility, components]}

  Map<String, List<String>> paramMap = Servlets.getRequestQueryStringMap(request); 
 }

 ...

}

·         in JSF, when FacesContext is available use, Faces#getRequestQueryStringMap(), or more clumsy (not recommended):

import org.omnifaces.util.Servlets;

...

// or simply use, Faces#getRequest()

FacesContext context = FacesContext.getCurrentInstance();

ExternalContext externalContext = context.getExternalContext();

HttpServletRequest request = (HttpServletRequest) externalContext.getRequest();

// e.g. request: http://localhost:8080/MyApp/faces/index.xhtml?tech=JSF&lib=OmniFaces&lib=PrimeFaces&type=utility&type=components

// map content: {tech=[JSF], lib=[OmniFaces, PrimeFaces], type=[utility, components]}

// Note: in order to preserve the query parameters over a JSF POST you may need, <o:formincludeRequestParams="true"> 

Map<String, List<String>> paramMap = Servlets.getRequestQueryStringMap(request);

API GH