Use class name as root key for JSON Jackson serialization

Suppose I have a pojo:

import org.codehaus.jackson.map.*;

public class MyPojo {
    int id;
    public int getId()
    { return this.id; }

    public void setId(int id)
    { this.id = id; }

    public static void main(String[] args) throws Exception {
        MyPojo mp = new MyPojo();
        mp.setId(4);
        ObjectMapper mapper = new ObjectMapper();
        mapper.configure(SerializationConfig.Feature.WRAP_ROOT_VALUE, true);
        System.out.println(mapper.getSerializationConfig().isEnabled(SerializationConfig.Feature.WRAP_ROOT_VALUE));
        System.out.println(mapper.writeValueAsString(mp));
    }
}

When I serialize using the Jackson ObjectMapper, I just get

true
{"id":4}

but I want

true
{"MyPojo":{"id":4}}

I've searched all over, Jacksons documentation is really unorganized and mostly out of date.

By adding the jackson annotation @JsonTypeInfo in class level you can have the expected output. i just added no-changes in your class.

package com.test.jackson;

import org.codehaus.jackson.map.ObjectMapper;
import org.codehaus.jackson.map.SerializationConfig;

import com.fasterxml.jackson.annotation.JsonTypeInfo;
import com.fasterxml.jackson.annotation.JsonTypeInfo.As;
import com.fasterxml.jackson.annotation.JsonTypeInfo.Id;

@JsonTypeInfo(include=As.WRAPPER_OBJECT, use=Id.NAME)
public class MyPojo {
    // Remain same as you have
}

output:

{
    "MyPojo": {
        "id": 4
    }
}

I'm not using jackson, but searching I found this configuration that seems to be what you want: WRAP_ROOT_VALUE

Feature that can be enabled to make root value (usually JSON Object but can be any type) wrapped within a single property JSON object, where key as the "root name", as determined by annotation introspector (esp. for JAXB that uses @XmlRootElement.name) or fallback (non-qualified class name). Feature is mostly intended for JAXB compatibility.

Default setting is false, meaning root value is not wrapped.

So that you can configure mapper:

objectMapper.configure(SerializationConfig.Feature.WRAP_ROOT_VALUE, true);

I hope it helps you...

Below is a way to achieve this

Map<String, MyPojo> singletonMap = Collections.singletonMap("mypojo", mp);
System.out.println(mapper.writeValueAsString(singletonMap));

Output { "mypojo" : { "id" : 4}}

Here the advantage is that we can give our on name for the root key of json object. By the above code, mypojo will be the root key. This approach will be most useful when we use java script template like Mustache.js for iteration of json objects

To achieve this you need to use the JsonTypeInfo annotation on your class and in particular WRAPPER_OBJECT

@JsonTypeName("foo")                                                                                         
@JsonTypeInfo(include = JsonTypeInfo.As.WRAPPER_OBJECT ,use = JsonTypeInfo.Id.NAME)

public class Bar(){
)

There is also a nice annotation for this:

@JsonRootName(value = "my_pojo")
public class MyPojo{
  ...
}

will generate:

{
  "my_pojo" : {...}
}

Use class name as root key for JSON Jackson serialization

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