[OmniFaces utilities] The 
getParams() returns an unmodifiable map with all request query string or view parameters, appended with all child 
UIParameter components (
<f|o:param>) of the given parent component. Those with 
disabled=true or an empty name or an empty value are skipped. The 
<f|o:param> will override any included view or request parameters on the same name.
Method:
Usage:
Let's suppose that we have the following page:
<f:metadata>
 <f:viewParam
name="playernameparam"
value="#{playersBean.playerName}"/>            
 <f:viewParam
name="playersurnameparam"
value="#{playersBean.playerSurname}"/> 
</f:metadata>
<h:head>
 <title></title>
</h:head>   
<h:body>     
 <h:panelGrid columns="2">
  <h:form id="form">
   <h:commandButton id="submit"
value="Get all params"
action="#{playersBean.allParams()}">    
   
<f:param name="ageParam" value="29"/>
   
<o:param name="playParam" value="left"/>
   </h:commandButton>
  </h:form>                  
 </h:panelGrid>
</h:body>
Further, we can use the 
Components#getParams()
utility to programmatically collect the 
UIParameters 
(
<f|o:param/>)
nested in the above 
<h:commandButton/>
and the view parameters. This can be accomplish in different JSF
artifacts; for example, in a bean (obviously, there are several ways to
identify the parent 
UIComponent
of the 
UIParameters
that we want to collect - the 
UIComponent
that should be passed to the 
#getParams()
should be obtained in a convenient manner depending on your circumstances;
below, we simply used the 
Components#findComponent()
utility):
import
org.omnifaces.util.Components;
...
public void
allParams() {
               
 UIComponent uc = Components.findComponent("form:submit");
 Map<String, List<String>>
paramsMap = Components.getParams(uc, false, true);
 for (Map.Entry<String,
List<String>> entry : paramsMap.entrySet()) {
      System.out.println("Param: "+
entry.getKey() + "/" + entry.getValue());
 }
}
Let's suppose that we start the application with an URL like this:
http://myapp/?playernameparam=rafael&playersurnameparam=nadal
After we press the Get
all params button the server log will reveal the following output:
Param:
playernameparam/[rafael]
Param:
playersurnameparam/[nadal]
Param:
ageParam/[29]
Param:
playParam/[left]