Use class name as root key for JSON Jackson serialization

Question

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I've searched all over, Jacksons documentation is really unorganized and mostly out of date.

Answer 1

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     } }