public class Callouts {
    public  static pageReference  makeGetCallout() {
        Http http = new Http();
        HttpRequest request = new HttpRequest();
        request.setEndpoint('http://www.xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx');
        request.setMethod('GET');
    
         
        HttpResponse response = http.send(request);
        // If the request is successful, parse the JSON response.
        if (response.getStatusCode() == 200) {
            // Deserializes the JSON string into collections of primitive data types.
            Map<String, Object> results = (Map<String, Object>) JSON.deserializeUntyped(response.getBody());
      
            List<Object> values = (List<Object>) results.get('values');
            System.debug('Received the following values:');
            for (Object value: values) {
                System.debug(value);
            }
        }
        return null;
    }
    public static pageReference makePostCallout() {
    String S ='{"Deduction": [{"Cxatxegoxry_Tyxpe": "xV","xxx": 125.00}],"isOxxnlinexxxxxr": true}';   
        Http http = new Http();
        HttpRequest request = new HttpRequest();
        request.setEndpoint(' http://xxxxxxxxxxxxxxxxxxxxxxxxxx');
        request.setMethod('POST');
        request.setHeader('Content-Type', 'application/json;charset=UTF-8');
        
           request.setHeader('ip', '2xxxxxxxxxx');
        request.setBody('S');
        HttpResponse response = http.send(request);
        // Parse the JSON response
        if (response.getStatusCode() != 201) {
            System.debug('The status code returned was not expected: ' +
                response.getStatusCode() + ' ' + response.getStatus());
        } else {
            System.debug(response.getBody());
        }
        return null;
    }        
}


v.f page is :
<apex:page controller="Callouts" > 
                   <apex:form >
                <apex:pageBlock >
   <apex:pageBlockSection >
       <apex:commandButton value="GET" action="{!makeGetCallout}"/>
       <apex:commandButton value="POST" action="{!makePostCallout}"/>
          </apex:pageBlockSection>
       </apex:pageBlock>
   </apex:form>

</apex:page>


iam not getting the response on clicking the button may i know where is the mistake?