Points To Remember

You need to add the following dependency to your project to use Spring Rest Template.

compile('org.springframework:spring-web:3.0.2.RELEASE')

How to get response from a server by HTTP GET call

Following are the methods that can be used to get the response from a url using HTTP GET method.

• getForObject()

  This method takes a URL, Response class (it tells that the response should be bound to this class).

  RestTemplate restTemplate = new RestTemplate();
  String response = restTemplate.getForObject("http://localhost:8080/someUrl",String.class);

  
  Following method will make a Http GET call with params.
  

  Map<String,String> params = new LinkedHashMap<String, String>();
  params.put("userId","1");
          
  RestTemplate restTemplate = new RestTemplate();
  String response = restTemplate.getForObject("http://localhost:8080/someUrl",String.class,params);

  
  
  This method does not give the following
  

  • Http status code for the GET call
  • Http headers of the response from the server

  In case you need these headers and status code then you might need to use the getForEntity() or exchange() methods.

• getForEntity()

  This method can be used to send a HTTP GET request to a url.

  RestTemplate restTemplate = new RestTemplate();
  ResponseEntity<String> response = restTemplate.getForEntity("http://localhost:8080/someUrl",String.class);

  Following method will make a Http GET call with params.
  

  Map params = new LinkedHashMap();
  params.put("userId","1");
  
  RestTemplate restTemplate = new RestTemplate();
  ResponseEntity<String> response = restTemplate.getForEntity("http://localhost:8080/someUrl",String.class);

  
  
  You can get the response as follows

  • Response Headers : response.getHeaders();
  • Status Code : response.getStatusCode();
  • Response Body : response.getBody();