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" : "FailedToParse" }
我不明白这里的光标选项是什么意思。该选项应该在哪里配置?
EDIT这是一个示例用户文档
{
"_id": "5a6df13552f42a34dcca9aa6",
"username": "user1",
"password": "$2a$10$p0OXq5PPa41j1e4iPcGZHuWjoKJ983sieS/ovFI.cVX5Whwj21WYi",
"favoriteItems": [
{
"_id": "5a0c6b2dfd3eb67969316d6d",
"name": "item1",
"city": "Rabat"
},
{
"_id": "5a0c680afd3eb67969316d0b",
"name": "item2",
"city": "Rabat"
}
]
}