Adding values to an Array in MongoDB with Java

问题

I have a document stored in a collection in a mongo database. I want to be able to add to two arrays that are already in the document.

Method for creating the document and arrays:

public void addNewListName(String listName) {

    MongoCollection<Document> collection = database.getCollection("lists");

    ArrayList< DBObject > array = new ArrayList< DBObject >();
    Document list = new Document ("name", listName)
            .append("terms", array)
            .append("definitions", array);
    collection.insertOne(list);
}

Method where I want to add values into the array:

public void addVocabToList(String listName, String newVocabTerm, String newDefinition) {

}

The picture shows what the document looks like in MongoDB Compass after the first method is executed

回答1:

Your addVocabToList() implementation will look something like this:

MongoCollection<Document> collection = database.getCollection("lists");

Document updatedDocument = collection.findOneAndUpdate(
    Filters.eq("name", listName),
    new Document("$push",
        new BasicDBObject("terms", new BsonString(newVocabTerm))
            .append("definitions", new BsonString(newDefinition))),
        new FindOneAndUpdateOptions().returnDocument(ReturnDocument.AFTER));

That code will:

Find the document having name=listName
Append the value of newVocabTerm to the terms array
Append the the value of newDefinition to the definitions array
Return the updated document (this part is optional)

来源：https://stackoverflow.com/questions/45597271/adding-values-to-an-array-in-mongodb-with-java

标签

java

arrays

mongodb