Mongo DB更新，使用Java驱动程序的聚合管道

<dependency>
    <groupId>org.mongodb</groupId>
    <artifactId>mongo-java-driver</artifactId>
    <version>3.12.10</version>
</dependency>

import com.mongodb.MongoClient;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;

// 创建MongoClient对象，连接到MongoDB数据库
MongoClient mongoClient = new MongoClient("localhost", 27017);
MongoDatabase database = mongoClient.getDatabase("mydb");
MongoCollection<Document> collection = database.getCollection("mycollection");

import org.bson.Document;
import com.mongodb.client.model.Aggregates;
import com.mongodb.client.model.Filters;
import com.mongodb.client.model.Updates;

// 构建聚合管道的更新操作
List<Bson> pipeline = Arrays.asList(
    Aggregates.match(Filters.eq("name", "John")),
    Aggregates.addFields(new Field<>("age", 30)),
    Aggregates.project(Projections.fields(Projections.excludeId()))
);

// 执行聚合管道的更新操作
collection.updateMany(Filters.eq("name", "John"), Updates.combine(
    Updates.set("age", 30),
    Updates.set("updated_at", new Date())
));