Call a rest service in a WADL via browser

Question

I have to call a rest service declared in a WADL but i dont know how to read the file on the description.

This is the file description for the service :

-<resources base="http://xxxxxxxxxxxx:8000/webservices/rest/User/">
-<resource path="change_user_name/">
-<method name="POST" id="CHANGE_USER_NAME">
-<request>
<representation type="CHANGE_USER_NAME_Input" mediaType="application/xml"/>
<representation type="CHANGE_USER_NAME_Input" mediaType="application/json"/>
</request>
</method>
</resource>
-<resource path="isuseractive__1/">
-<method name="POST" id="ISUSERACTIVE__1">
-<request>
<representation type="ISUSERACTIVE__1_Input" mediaType="application/xml"/>
<representation type="ISUSERACTIVE__1_Input" mediaType="application/json"/>
</request>
-<response>
<representation type="ISUSERACTIVE__1_Output" mediaType="application/xml"/>
<representation type="ISUSERACTIVE__1_Output" mediaType="application/json"/>
</response>
</method>
</resource>

And this is the detail description for that method

<import schemaLocation="http://xxxxxxxxxxxxxxx:8000/webservices/rest/User/?XSD=RESTHeader.xsd" namespace="http://xmlns.oracle.com/apps/fnd/rest/header"/>
-<element name="InputParameters">
-<complexType>
-<sequence>
<element db:type="VARCHAR2" type="string" name="P_USERNAME" nillable="true" minOccurs="0" db:index="1"/>
</sequence>
</complexType>
</element>

I have tried calling the service with POSTMAN :

http://xxxxxxxxxxxx:8000/webservices/rest/User/Isuseractive__1/ISUSERACTIVE__1

authoritation:

user:xxxx
password:xxx

body:

{
    "root":{
        "P_USERNAME":"Perico"
    }
}

and it works fine.

But when i try it with a browser call, i get a 400 error page.

I tried

http://xxxxxxxxxxxx:8000/webservices/rest/User/Isuseractive__1/ISUSERACTIVE__1?P_USERNAME=PERICO

http://xxxxxxxxxxxx:8000/webservices/rest/User/Isuseractive__1/ISUSERACTIVE__1?P_USERNAME="PERICO"

and more combinations, but nothing worked.