我在文档中有一个数组。
{
"id" : "id_1",
"name" : "name_1";
"additionalData" : [
{
"additionalDataId" : "id_1_1",
"additionalDataName" : "name_1_1",
"longText" : "A long story about..."
},
{
"additionalDataId" : "id_1_2",
"additionalDataName" : "name_1_2",
"longText" : "A longer story about danger..."
},
{
"additionalDataId" : "id_1_3",
"additionalDataName" : "name_1_3",
"longText" : "A longer story about danger and courage"
},
]
}
检索名为的数组元素
"name_1_2"
db.collection.find( { name: "name_1"},
{ _id: 0, additionalData: { $elemMatch: { "additionalDataName": "name_1_2" } }
})
如何使用
mongoTemplate
?
我试过了
Aggregation aggregation = Aggregation.newAggregation(
Aggregation.match(
Criteria.where("name").is("name_1").and("additionalData.additionalDataName").is("name_1_2")
),
Aggregation.project("additionalData"),
mongoTemplate.aggregate(聚合,“客户对象”,对象.类);
我也试着用
ArrayOperators.Filter.filter
Aggregation aggregation = Aggregation.newAggregation(
Aggregation.match(Criteria.where("name").is("name_1")),
Aggregation.project("additionalData").and(
ArrayOperators.Filter.filter("additionalData").as("item")
.by(ComparisonOperators.valueOf("item.additionalDataName").equalTo("name_1_2"))
)
);
mongoTemplate.aggregate(aggregation, "CustmObjects", Object.class);
https://stackoverflow.com/a/46769125/4587961
总之,我得到的结果是数组的所有元素。