如何在 Spring Mongo 中调用 MongoDB addFields? [英] How to call MongoDB addFields in Spring Mongo?

问题描述

我的 MongoDB 中有以下类型的对象

I have the following type of object in my MongoDB

{
    ...,
    "name": {
        "en": "...",
        "am": "...",
        "ru": "..."
    },
    ...
}

现在我想使用 Spring Data Mongo 运行以下查询

Now I want to run the following query using Spring Data Mongo

db.categories.aggregate({$addFields: {'name': '$name.am'}})

其中 $name.am 中的 am 部分是名称的语言环境，因此它必须是动态的.我查看了 MongoTemplate API，据我所知，不支持 addFields 操作.有什么办法可以做到这一点吗?

where the am part in $name.am is the locale of the name, hence it must be dynamic. I looked through the MongoTemplate API, and as far as I found, there is no support of addFields operation. Is there any way to achieve this?

推荐答案

你需要实现 AggregationOperation

AggregationOperation addFields = new AggregationOperation() {

    @Override
    public Document toDocument(AggregationOperationContext context) {
        return new Document("$addFields", new Document("name", "$name.am"));
    }

};

通用

public AggregationOperation aggregateAddFields(final String field, final String valueExpresion) {

    AggregationOperation addFields = new AggregationOperation() {

        @Override
        public Document toDocument(AggregationOperationContext context) {
            return new Document("$addFields", new Document(field, valueExpresion));
        }
    };

    return addFields;
}

...

AggregationOperation addFields = aggregateAddFields("name", "$name.am");

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