MongoDb和java dao实现

import com.mongodb.MongoClient;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoDatabase;
import org.bson.Document;

public class UserDao {
    private MongoClient mongoClient;
    private MongoDatabase database;
    private MongoCollection<Document> collection;

    public UserDao() {
        mongoClient = new MongoClient("localhost", 27017);
        database = mongoClient.getDatabase("mydb");
        collection = database.getCollection("users");
    }

    public void addUser(User user) {
        Document document = new Document("name", user.getName())
                .append("age", user.getAge())
                .append("email", user.getEmail());
        collection.insertOne(document);
    }

    public User getUser(String name) {
        Document query = new Document("name", name);
        Document result = collection.find(query).first();
        if (result != null) {
            return new User(result.getString("name"), result.getInteger("age"), result.getString("email"));
        }
        return null;
    }

    // 其他操作方法...

    public void close() {
        mongoClient.close();
    }
}