小编Ham*_*mza的帖子

执行以下聚合管道:

public void getMostLikedItems () {
        UnwindOperation unwind = Aggregation.unwind("favoriteItems");
        GroupOperation group = Aggregation.group("favoriteItems").count().as("likes");
        SortOperation sort = Aggregation.sort(Sort.Direction.DESC, "likes");

        Aggregation aggregation = newAggregation(unwind, group, sort);
        DBObject result = mongoTemplate.aggregate(aggregation, "users", LikedItem.class).getRawResults();
}

抛出以下异常:

com.mongodb.MongoCommandException: Command failed with error 9: 'The 'cursor' option is required, except for aggregate with the explain argument' on server localhost:27017. The full response is { "ok" : 0.0, "errmsg" : "The 'cursor' option is required, except for aggregate with the explain argument", "code" : 9, "codeName" …

我希望反序列化使空数组失败。以下代码有效，但我想让这个特定案例失败：

use serde::Deserialize;

#[derive(Debug)]
#[derive(Deserialize)]
struct Doc {
    nums: Vec<i32>
}

fn main(){
    let data = r#"
        {"nums": []}
    "#;
    let doc: Doc = serde_json::from_str(data).unwrap();
    dbg!(doc);
}

有什么选择可以实现这一目标？