Querying Mongo Collection using QueryBuilder in Mongo 3.3.0

问题

Our code with mongo-java-driver 3.0.4 used to be like -

DBCollection dbCollection = mongoClient.getDB(databaseName).getCollection(collectionName);
QueryBuilder queryBuilder = new QueryBuilder();
/** queryBuilder.put() for building the query */
DBCursor dbCursor = dbCollection.find(queryBuilder.get());
while(dbCursor.hasNext()) {
    DBObject dbObject = dbCursor.next();
    // add entries to a list of TDocument type
}

Converting this to the mongo-java-driver 3.3.0, I ended up with this -

MongoCollection<TDocument> collection = database.getCollection(collectionName, TDocument.class); //where TDocument is custom document class of ours
QueryBuilder queryBuilder = new QueryBuilder();
/** queryBuilder.put() for building the query */
FindIterable<TDocument> tDocumentList = collection.find(queryBuilder.get()); //this is not compiling
for (TDocument element : tDocumentList) {
    names.add(element.getName()); //addition to some list of TDocument type
}

But the point is I am still not able to compile the source for the find operation on the MongoDB collection that I have defined.

What needs to be corrected here? I would want to stick to any preferred implementation that helps in upgrading mongo to 3.3.0+.

Edit - My TDocument class (named differently below from the lib name) class is a simple POJO as -

public class TDocType {

    private TDocType() {
    }

    String one;

    @NotNull
    String name;

    String third;

    String fourth;

    // getter and setter for all the above
}

回答1:

Cast to Bson.

 FindIterable<TDocument> tDocumentList = collection.find((Bson)queryBuilder.get());

Update:: Change to use the filters from Mongo 3.3.0

Bson filter = Filters.eq("field", "value");
FindIterable<TDocument> tDocumentList = collection.find(filter);

回答2:

You could replace your query builder by a org.bson.Document like this :

Document query = new Document();
query.put(parameterName, parameterValue);

And then

FindIterable<TDocument> tDocumentList = collection.find(query); //this is not compiling

来源：https://stackoverflow.com/questions/40178038/querying-mongo-collection-using-querybuilder-in-mongo-3-3-0

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java

mongodb

mongodb-query

mongodb-java