在MongoDB中将对象数组反序列化为JSON

Question

I am using Morphia (ver 0.99) for my JSON to Pojo mapping to my MongoDB (ver 2.0). Streaming data between web-clients and my server works fine. But now I have a use-case where I don't know what pattern that is most appropriate. Can I use Morphia or MongoDB Java driver to achieve my requirements or do I need to use Jackson and JPA 2.2 notation.

Here is my use-case;

1. Invoke Morphia query on selected collection (MongoDB)
2. The use the resulting ArrayList of Pojos for business logic and presentation (Primefaces)
3. Also convert the resulting ArrayList of Pojo's to JSON array of objects, but remove Pojo properties in the conversions that is not needed in the web-client
4. Push the converted JSON to the web-client for presentation

Converting one Pojo is straight forward with Morphia, but how do I convert an array?

return morph.toDBObject(obj).toString();

Is there a notation like @JsonIgnore in Morphia to ignore conversions to and from JSON ?

How can I most efficiently (without using more libraries if possible) to solve step three in in my use-case. Convert ArrayList to JSON and ignore conversion of some of the Pojo properties?

Answer 1

I've come up with a solution to my problem. It's maybe not the most elegant but it works the way I want and I don't have to include other libraries (like Gson and Jackson) to de-serialize my array list of Pojo's to Json, I only used classes from the MongoDB Java driver and the Morphia API. I also added a simple parameter list to strip away unnecessary property value to be pushed to the client.

public static String deserializeToJSON(List<?> objList, String... removeAttributes) {
    List<DBObject> dbObjList = new ArrayList<>(objList.size());
    DBObject dbObj;
    for(Object obj :objList){
        dbObj = morph.toDBObject(obj);
        for(int i=0; i < removeAttributes.length; i++){
        debug("Removed DBObject filed: " +dbObj.removeField(removeAttributes[i]));                                    
        }
        dbObjList.add(dbObj);
    }             
    String json = JSON.serialize(dbObjList);
    return json;
}