CODEWITHSUNDEEP
javajsonspringspring-mvc
user2219247
user2219247

Reputation: 1313

Renaming JSON objects returned to ResponseBody in Spring MVC

Lets say I have a list of objects like this: LinkedList<JsonAssessment> jsonAssessments....

It is returned to this kind of method:

@RequestMapping(value = "mapping", method = RequestMethod.POST)
public
@ResponseBody
List<JsonAssessment> doSomething(....) {
    .....
}

I am making AJAX call to this controller everything is working correctly as expected but I don't like the naming my JSON is returned. In firebug I am seeing:

{"LinkedList":[{"assessmentName":"........

The question is how can I rename that root element LinkedList? Is there any config I have to set?

EDIT

I do not want to use any wrapper objects.

EDIT

My ObjectMapper:

public class JsonObjectMapper extends ObjectMapper {

    public JsonObjectMapper() {
        super();
        this.configure(DeserializationFeature.UNWRAP_ROOT_VALUE, true);
        this.configure(SerializationFeature.WRAP_ROOT_VALUE, true);
        this.setSerializationInclusion(JsonInclude.Include.NON_NULL);
    }

}

Spring: 3.2.4.RELEASE Jackson: 2.1.2

EDIT

This object mapper is declared in MVC message converters:

<mvc:annotation-driven content-negotiation-manager="contentNegotiationManager">
    <mvc:message-converters>
        <bean class="org.springframework.http.converter.json.MappingJackson2HttpMessageConverter">
            <property name="objectMapper" ref="jsonObjectMapper"/>
        </bean>
    </mvc:message-converters>
</mvc:annotation-driven>

And that is what I've tried with naming strategy:

public class JsonPropertyNamingStrategy extends PropertyNamingStrategy {

    public static final MyNamingStrategy MY_NAMING_STRATEGY = new MyNamingStrategy();

    private static final LinkedHashMap<String, String> PROPERTIES = new LinkedHashMap<String, String>() {{
        put("LinkedList", "resultList");
    }};

    public static class MyNamingStrategy extends PropertyNamingStrategyBase {

        @Override
        public String translate(String propertyName) {
            if (propertyName == null) {
                return null;
            }

            if (PROPERTIES.containsKey(propertyName)) {
                return PROPERTIES.get(propertyName);
            }

            return propertyName;
        }

    }

}

I was debugging it and when it comes to translate method property names comes all except the root element. I have everything that LinkedList contains, but LinkedList is not coming to this method.

Upvotes: 3

Views: 11694

Answers (3)

M. Deinum
M. Deinum

Reputation: 125232

Instead of directly returning a the List, wrap it inside a ResponseEntity that will give you a response without a root element

@RequestMapping(value = "mapping", method = RequestMethod.POST)
public
@ResponseBody ResponseEntity<List<JsonAssessment>> doSomething(....) {
.....
return new ResponseEntity(yourList);
}

That way you don't have a root element. If you still want a root element you could add it to a Map. Results in the following JSON "[{"assessmentName":"........]

@RequestMapping(value = "mapping", method = RequestMethod.POST)
public
@ResponseBody ResponseEntity<Map<String, List<JsonAssessment>>> doSomething(....) {
.....
Map results = new HashMap();
result.put("assesments", yourlist);
return new ResponseEntity(results);
}

Should output {"assesments":[{"assessmentName":"........

Although you are stilling wrapping the objects here, it is in objects that are freely available, you don't have to add your own custom classes.

This is what we are using in a couple of our @Controllers, we are using Spring 3.2 and Jackson 2.2.

Upvotes: 3

schomax
schomax

Reputation: 337

If you are using Jackson Mapper you can use Annotations to define names of properties in classes by

@JsonProperty("foo")

or set the order by

@JsonPropertyOrder({"foo", "bar"})

and so on.

See further Jackson Annotations

edit: Sorry, just saw the wrapper-comment. The only solution i saw is using a wrapper like this: How to rename root key in JSON serialization with Jackson

Upvotes: 0

NimChimpsky
NimChimpsky

Reputation: 47300

put the list in a wrapper class is a a commonly implemented strategy

Upvotes: 0

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