I stumbled upon this effective solution that involves using a custom deserializer.
I established a limit on the number of permissible packages, but you can opt to omit this check if it's not required.
Class Response:
import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
import lombok.Getter;
import lombok.Setter;
import lombok.ToString;
@Getter
@Setter
@ToString
@JsonDeserialize(using = ResponseDeserializer.class)
public class Response {
private String message;
private Package [] packages;
}
Class Package:
import lombok.Getter;
import lombok.Setter;
import lombok.ToString;
@Getter
@Setter
@ToString
public class Package {
private String packageCode;
private String packageNum;
}
Class ResponseDeserializer:
import java.io.IOException;
import java.util.ArrayList;
import java.util.List;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.DeserializationContext;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.deser.std.StdDeserializer;
public class ResponseDeserializer extends StdDeserializer<Response> {
private static final long serialVersionUID = -6665611685508708642L;
private static final long MAX_PACKAGE_NUM = 1000;
private ObjectMapper objectMapper = new ObjectMapper();
public ResponseDeserializer() {
this(null);
}
public ResponseDeserializer(Class<?> vc) {
super(vc);
}
@Override
public Response deserialize(JsonParser parser, DeserializationContext ctx)
throws IOException {
final JsonNode node = parser.getCodec().readTree(parser);
final String message = node.get("message").asText();
final List<Package> packageList = new ArrayList<>();
for (var key = 1; key < MAX_PACKAGE_NUM; key++) {
var packageNode = node.get(String.valueOf(key));
if (null == packageNode) {
break;
}
var currentPackage = objectMapper.treeToValue(packageNode, Package.class);
packageList.add(currentPackage);
}
final var response = new Response();
response.setMessage(message);
response.setPackages(packageList.toArray(new Package[0]));
return response;
}
}
Class TestDeserializer (sample):
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonMappingException;
import com.fasterxml.jackson.databind.ObjectMapper;
public class TestDeserializer {
public static void main(String[] args) throws JsonMappingException, JsonProcessingException {
String responseJSON = """
{
"message" : "message",
"1": {
"packageCode": "packageCode1",
"packageNum": "packageNum1"
},
"2": {
"packageCode": "packageCode2",
"packageNum": "packageNum2"
}
}
""";
Response response = new ObjectMapper().readValue(responseJSON, Response.class);
System.out.println(response.toString());
}
}