Convert a SQL ResultSet to json format

ResultSetToJson.java

import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.node.ArrayNode;
import com.fasterxml.jackson.databind.node.ObjectNode;

import java.sql.ResultSet;
import java.sql.ResultSetMetaData;
import java.sql.SQLException;

public class ResultsetConverter {
    public static JsonNode convertToJson(ResultSet rs){
        if(rs == null) return null;
        ObjectMapper mapper = new ObjectMapper();
        try {
            ResultSetMetaData rsmd = rs.getMetaData();
            ObjectNode first = null;
            ArrayNode array = null;
            if(rs.next()){
                first = getObjectNode(rs, mapper, rsmd);
            }
            while(rs.next()){
                if(array == null){
                    array = mapper.createArrayNode();
                    array.add(first);
                }
                array.add(getObjectNode(rs, mapper, rsmd));
            }
            return array == null ? first : array;
        } catch (SQLException e) {
            e.printStackTrace();
            return null;
        }
    }

    private static ObjectNode getObjectNode(ResultSet rs, ObjectMapper mapper, ResultSetMetaData rsmd){
        ObjectNode obj = mapper.createObjectNode();
        try {
            int columnCount = rsmd.getColumnCount();
            for(int i = 1; i <= columnCount; i++){
                String column = rsmd.getColumnName(i);
                Object value = rs.getObject(i);
                if(value == null){
                    obj.putNull(column);
                }else if(value instanceof String){
                    obj.put(column, (String) value);
                }else if(value instanceof Integer){
                    obj.put(column, (Integer) value);
                }else {
                    throw new IllegalArgumentException("Unmappable object type: " + value.getClass());
                }
            }
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return obj;
    }
}