Points To Remember

Add the following dependency to the gradle project.

compile('com.fasterxml.jackson.core:jackson-databind:2.7.1-1')

Read JSON in Filter and bind it to POJO class

So, in this way you can read JSON from the request and bind it to the any custom class.

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();