Spring Boot @RestController cannot auto convert response to JSON

Question

I am running into a small trouble here with a Spring Boot Application. As per my understanding, Jackson dependency is auto configured with the spring-boot-starter-web and serialize/deserialize objects into json for the classes annotated as @RestController.

The issue is it is not having the same behavior as expected instead it is returning the response back in plain/text format.

Below are the code snippet that i am trying to execute.

@GetMapping(value = "/user/",produces = "application/JSON")
public List<String> getUser(){

    List<String> newUsers = new ArrayList<String>();
    newUsers.add("User 1");
    newUsers.add("User 2");
    newUsers.add("User 3");
    return newUsers;
}

Response: Can someone please tell me what exactly i am doing wrong here?

Thanks J

Answer 1

Yup , just a JSON array is also a valid JSON . If you want to output the JSON in the object form like :

{
   "users":["User 1","User 2","User 3"]
}

You can do :

@GetMapping(value = "/user/",produces = "application/JSON")
public Map<String,Object> getUser(){
    Map<String,Object> result = new HashMap<String,Object>();
    List<String> newUsers = new ArrayList<String>();
    newUsers.add("User 1");
    newUsers.add("User 2");
    newUsers.add("User 3");
    result.put("users" , newUsers);
    return result;
}