call url in service web java spring

I need call a web services in an url and later modify json that I recieve, but I dont obtain the result correct. I use spring mvc.

I have this code java:

@RequestMapping(value = "/test", produces = "application/json")
@ResponseBody
public String infoSist() throws Exception {
    base = new URL("http://localhost:" + port + "/metrics");
    template = new RestTemplate();
    ResponseEntity<String> infoSist =  template.getForEntity(base.toString(), String.class);
    System.out.printf("Exit: \n\n  %s",infoSist.getBody()); 
    return infoSist.getBody();  
}

I dont obtain infoSist the json of return the URL, this show the code html of login page. What is the problem?

thank you very much!