Collecting unmapped fields with Object Mapper
Jackson is a popular Java library to convert JSON to Java Object. It maps JSON field with object field by name or mapping provided by @JsonProperty.
Jackson provides @JsonAnySetter for collecting unmapped or unrecognized fields.
class Profile {
String name;
Map<String, String> unmappedFields = new HashMap<>();
public void setName(String name) {
this.name = name;
}
// for collecting unmapped field
@JsonAnySetter
public void unmappedFields(String key, String value){
// ... Do what you want
unmappedFields.put(key, value);
}
}
In action
/* Consider JSON
{
"name": "m8ty",
"handler": "@DM8tyProgrammer"
}
*/
Profile p = objectmapper.read(json, Profile.class);
// print "m8ty"
System.out.println(p.name);
// print "{handler=@DM8tyProgrammer}"
System.out.println(p.unmatchedFields);