SALESFORCE1(AURA PLATFORM): How to pass values from a client-side-code(JavaScript code) to server-side-code(APEX)?

Question

I am working on Salesforce1 (Aura platform). I am trying to pass values from client-side (javascript) to server-side controller(Apex-code). I tried by using setParams(); in JavaScript and @key annotation in Apex but @key is not supported in Apex.

Thanks in advance.

I am giving sample code here...

APPLICATION code:

     <aura:application>
      <PlumQ:example/>
     </aura:application>

COMPONENT code:

<aura:component model="PlumQ.ExampleServerSideController">

  <aura:attribute name="firstName" type="String" default="HELLO worlD"/>

  <ui:inputtext label="Name" aura:id="id1" value="{!v.firstName}" placeholder = "enter name" />

   <ui:button label="Native Aura Button" press="{!c.echo}"/>

</aura:component>

**client-side-controller(JAVASCRIPT):**

 ({
   "echo" : function(component) {

          alert('in client-Side-process');

          var b =component.get("v.firstName");
          alert('firstnaaaaame:::::::::::::'+b);
           var a = component.get("m.serverEcho");
           alert('After ServerSide Process');
          a.setParams({ firstName : component.get("v.firstName") });



           a.setCallback(this, function(action) {

                        if (action.getState() === "ERROR") {
                                     alert("Server Error: " + action.getError()[0].message);
                          }
                        else{

                                     alert("From server: " + action.getReturnValue());

                       }
});

             $A.enqueueAction(a);

} })

server-side-controller(APEX CLASS):

  public class ExampleServerSideController {


  @AuraEnabled
  public static String serverEcho(@Key("firstName") String firstName){

  System.out.println("In Example Trival controllerrrrr"+firstName);

  return ("From server: " +firstName);

   }

  }

Answer 1

Your code is almost right. You only need to put quotation marks(") around firstName and remove @Key annotation from your apex controller. So your JS would look like:

a.setParams({
  "firstName" : component.get("v.firstName")
});

And your apex:

public static String serverEcho(String firstName)