Customize serialization of a list of JAXB objects to JSON? - json

Question

I am planning to serialize list of JAXB objects to JSON response. Currently below is the format I am getting. In the below response I am seeing one more object in between is "systemInfoList" which actually is showing the array. Instead I want the dependent_systems_infos should directly show array []. Also if there is a single system info response also still it should should show in the array format. I am using the Jackson parser, cxf.
Format currently I am getting:
{
"dependent_systems_infos":{
"systemInfoList":[
{
"system_name":"PZ_Service",
"system_type":"Internal",
"service_infos":[
{
"service_name":"getPZAttributes",
"status":"DOWN",
"response_time_ms":50
}
]
},
{
"system_name":"OMS",
"system_type":"External",
"service_infos":[
{
"service_name":"CreateOrder",
"status":"UP",
"response_time_ms":2000
},
{
"service_name":"CancelOrder",
"status":"UP",
"response_time_ms":500
}
]
}
]
}
}
Format I need:
{
dependent_system_infos : [
{
system_name : 'OMS'
system_type: 'External'
services_infos: [
{
service_name : 'CreateOrder'
status : 'UP'
response_time_ms : 2000
},
{
service_name : 'CancelOrder'
status : 'UP'
response_time_ms : 2000
}
]
},
{
system_name : 'PZ_Service'
system_type: 'Internal'
services_infos: [
{
service_name : 'getPZAttributes'
status : 'UP'
response_time_ms : 2000
}
]
}
]
}
JAXB classes I wrote:
#XmlRootElement(name = "dependent_systems_infos")
#XmlAccessorType(XmlAccessType.FIELD)
public class ItineraryStatusResponse {
private List<SystemInfo> systemInfoList;
#XmlList
public List<SystemInfo> getSystemInfoList() {
return systemInfoList;
}
public void setSystemInfoList(List<SystemInfo> systemInfoList) {
this.systemInfoList = systemInfoList;
}
}
#XmlType(propOrder = {
"systemName",
"systemType",
"serviceInfoList"
})
#XmlAccessorType(XmlAccessType.FIELD)
public class SystemInfo {
#XmlElement(name = "system_name", required = true)
protected SystemName systemName;
#XmlElement(name = "system_type", required = true)
protected SystemType systemType;
#XmlElement(name = "service_infos", required = true)
protected List<ServiceInfo> serviceInfoList;
}

Answer 1

It would help to know how you're generating the output, but the main issue is that you are serializing a root object that contains a list when you really only want to serialize the list itself. What would you expect the outputted list to look like if ItineraryStatusResponse had other fields in it?
You can remove the #XmlRootElement annotation and mark the list as an element named "dependent_systems_infos":
#XmlAccessorType(XmlAccessType.FIELD)
public static class ItineraryStatusResponse {
private List<SystemInfo> systemInfoList;
#XmlElement(name = "dependent_systems_infos", required = true)
public List<SystemInfo> getSystemInfoList() {
return systemInfoList;
}
public void setSystemInfoList(List<SystemInfo> systemInfoList) {
this.systemInfoList = systemInfoList;
}
}
If you are doing the serialization yourself, another approach would be to drop the ItineraryStatusResponse object entirely (since it's just a wrapper around the list), and then serialize the list itself with SerializationFeature.WRAP_ROOT_VALUE = true and a root name you provide:
ObjectMapper mapper = new ObjectMapper();
mapper.configure(SerializationFeature.WRAP_ROOT_VALUE, true);
AnnotationIntrospector introspector = new JaxbAnnotationIntrospector(TypeFactory.defaultInstance());
mapper.setAnnotationIntrospector(introspector);
ObjectWriter writer = mapper.writerWithDefaultPrettyPrinter().withRootName("dependent_systems_infos");
System.out.println(writer.writeValueAsString(systemInfoList));
Both of these approaches provide the desired output in my testing with Jackson 2.2.