Generating JSON from POJO for a specific scenario

Question

I have used Jackson and JSONObject to generate a plain JSON - things are fine here. I have a specific case where my pojo looks like below and i need the JSON is the specified format.

package test;

import javax.xml.bind.annotation.XmlRootElement;

@XmlRootElement(name = "login")
public class LoginApi implements IRestBean {

private String username;
private String password;
private String sfSessionId;
private String sfServerUrl;

public String getUsername() {
    return username;
}

public void setUsername(String username) {
    this.username = username;
}

public String getPassword() {
    return password;
}

public void setPassword(String password) {
    this.password = password;
}

public String getSfSessionId() {
    return sfSessionId;
}

public void setSfSessionId(String sfSessionId) {
    this.sfSessionId = sfSessionId;
}

public String getSfServerUrl() {
    return sfServerUrl;
}

public void setSfServerUrl(String sfServerUrl) {
    this.sfServerUrl = sfServerUrl;
}
}

The JSON that i am able to generate looks like this:

{
 "username" : null,
 "password" : null,
 "sfSessionId" : null,
 "sfServerUrl" : null
}

But this is not my requirement - i need the JSON in the below format so that my server accepts this as a valid JSON:

{
 "@type":"login",
 "username":"username@domain.com",
 "password":"password",
 "sfSessionId":null,
 "sfServerUrl":null
 }

Please help. Thanks in advance!

Answer 1

Change the IRestBean interface to include the @JsonTypeInfo annotation:

@JsonTypeInfo(use=JsonTypeInfo.Id.NAME, include=JsonTypeInfo.As.PROPERTY, property="@type")
public interface IRestBean {
    ...
}

Next, annotate the LoginApi class with @JsonTypeName:

@XmlRootElement(name = "login")
@JsonTypeName("login")
public class LoginApi implements IRestBean {
    ...
}

These are both Jackson-specific annotations.