db.getCollection("website_sort").aggregate([ { $match: { "websiteCategoryId": "63c27b11d5957b16c46dc17e" } }, { "$project": { id: { "$toObjectId": "$websiteListId" } } }, { "$lookup": { "from": "website_list_cs", "localField": "id", //A表需要关联的键 "foreignField": "_id", //B表需要关联的键 "as": "B_list" //B表的别名，下面输出B表字段时用到 } }, { $project: { id: 1, "B_list.title": 1, "B_list.desc": 1, "B_list.labels": 1, "B_list.link": 1, "B_list.logo": 1, "B_list.vpn": 1, "B_list.snapshot": 1, "B_list.recommend": 1, "B_list.vpn": 1, "B_list.status": 1 } }, { "$sort": { "id": 1 } } ]);转java

Here's an example Java code to execute the given MongoDB aggregation query:

import com.mongodb.client.AggregateIterable;
import com.mongodb.client.MongoClient;
import com.mongodb.client.MongoClients;
import com.mongodb.client.MongoDatabase;
import com.mongodb.client.model.Filters;
import org.bson.Document;

import java.util.Arrays;

public class MongoAggregationExample {

    public static void main(String[] args) {
        // Create MongoDB client
        MongoClient mongoClient = MongoClients.create("mongodb://localhost:27017");

        // Get reference to the database
        MongoDatabase database = mongoClient.getDatabase("yourDatabaseName");

        // Build the aggregation pipeline
        AggregateIterable<Document> result = database.getCollection("website_sort").aggregate(Arrays.asList(
                new Document("$match", Filters.eq("websiteCategoryId", "63c27b11d5957b16c46dc17e")),
                new Document("$project", new Document("id", new Document("$toObjectId", "$websiteListId"))),
                new Document("$lookup", new Document("from", "website_list_cs")
                        .append("localField", "id")
                        .append("foreignField", "_id")
                        .append("as", "B_list")),
                new Document("$project", new Document("id", 1)
                        .append("B_list.title", 1)
                        .append("B_list.desc", 1)
                        .append("B_list.labels", 1)
                        .append("B_list.link", 1)
                        .append("B_list.logo", 1)
                        .append("B_list.vpn", 1)
                        .append("B_list.snapshot", 1)
                        .append("B_list.recommend", 1)
                        .append("B_list.vpn", 1)
                        .append("B_list.status", 1)),
                new Document("$sort", new Document("id", 1))
        ));

        // Print the result
        for (Document doc : result) {
            System.out.println(doc.toJson());
        }

        // Close the MongoDB client
        mongoClient.close();
    }
}

Make sure to replace "yourDatabaseName" with the name of your actual database. Also, don't forget to add the necessary MongoDB Java driver to your project's dependencies.