Spring rest json post null values

Question

I have a Spring rest endpoint doing a simple hello app. It should accept a {"name":"something"} and return "Hello, something".

My controller is:

@RestController
public class GreetingController { 

    private static final String template = "Hello, %s!";

    @RequestMapping(value="/greeting", method=RequestMethod.POST)
    public String greeting(Person person) {
        return String.format(template, person.getName());
    }

}

Person:

public class Person {

    private String name;

    public Person() {
        this.name = "World";
    }

    public Person(String name) {
        this.name = name;
    }

    public String getName() {
        return this.name;
    }

    public void setName(String name) {
        this.name = name;
    }
}

When I make a request to the service like

curl -X POST -d '{"name": "something"}' http://localhost:8081/testapp/greeting

I get

Hello, World!

Looks like it isn't deserializing the json into the Person object properly. It's using the default constructor and then not setting the name. I found this: How to create a POST request in REST to accept a JSON input? so I tried adding an @RequestBody on the controller but that causes some error about "Content type 'application/x-www-form-urlencoded;charset=UTF-8' not supported". I see that is covered here: Content type 'application/x-www-form-urlencoded;charset=UTF-8' not supported for @RequestBody MultiValueMap which suggests removing the @RequestBody

I have tried removing the default constructor which it doesn't like either.

This question covers null values REST webservice using Spring MVC returning null while posting JSON but it suggests adding @RequestBody but that conflicts with above...

Answer 1

You must set 'produces' with @RequestMapping(value="/greeting", method=RequestMethod.POST)

use below code

@RequestMapping(value="/greeting", method=RequestMethod.POST, produces = { MediaType.APPLICATION_JSON_VALUE, MediaType.APPLICATION_XML_VALUE })
 public String greeting(@RequestBody Person person) {
        return String.format(template, person.getName());
    }

Answer 2

You must set the @RequestBody to tell to Spring what should be use to set your personparam.

 public Greeting greeting(@RequestBody Person person) {
    return new Greeting(counter.incrementAndGet(), String.format(template, person.getName()));
}