[FIXED] How to use RestTemplate for a POST request for a complex body in Java?

Issue

I'm working with RestTemplate in a Spring Boot project and I try to call a POST. And I'm using this code:

HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);

MultiValueMap<String, String> map= new LinkedMultiValueMap<String, String>();
map.add("email", "[email protected]");
map.add("id", "1234567");

HttpEntity<MultiValueMap<String, String>> request = new HttpEntity<MultiValueMap<String, String>>(map, headers);

ResponseEntity<Employ> response = restTemplate.postForEntity(
        "url", request , Employ.class );

Now I want to use RestTemplate to consume a POST request but for a complex object. So the body should look like this:

{
"SomeThing":{
  "Expr":"cdjhcdjh" 
},
"SomeInfo":{
 "Progr":"EVZpoiuyt",
 "Other": "{code: \"abcd\", password:\"12345\"}"
 }
}

How can I create the Map for this body? Any feedback will be apreciated. Thank you!

Solution

You should create Java objects (POJO) representing the data you would like to send via RestTemplate.

For example:

public class ObjectToPost {
  private SomeThing someThing;
  private SomeInfo someInfo;

 // getters & setters
}

public class SomeThing {
 private String expr;
     
 // getters & setters
}

public class SomeInfo {
  private String progr;
  private String other;
     
  // getters & setters
}

Then you could use this object in your RestTemplate.

ObjectToPost obj = new ObjectToPost();
obj.setSomeThing(...)
obj.setSomeInfo(...)
restTemplate.postForEntity("url", obj , Employ.class);

You could also use a Map but it will make it quite complex. If you really would like to achieve it with a Map you should create a <String,Object> map like:

  MultiValueMap<String, Object> map= new LinkedMultiValueMap<String, Object>();
  MultiValueMap<String, MultiValueMap<String, Object>> somethingMap = new LinkedMultiValueMap<String, Object>();
  something.put("SomeThing", Map.of("Expr","cdjhcdjh");
  map.put(somethingMap);

Answered By - MevlütÖzdemir
Answer Checked By - Mildred Charles (JavaFixing Admin)