如何在go mongo驱动程序库中使用Find().Select().One()

package main

import (
    "context"
    "fmt"
    "log"
    "go.mongodb.org/mongo-driver/bson"
    "go.mongodb.org/mongo-driver/mongo"
    "go.mongodb.org/mongo-driver/mongo/options"
)

type Person struct {
    Name  string `bson:"name"`
    Age   int    `bson:"age"`
    Email string `bson:"email"`
}

func main() {
    // 设置客户端连接配置
    clientOptions := options.Client().ApplyURI("mongodb://localhost:27017")

    // 连接到MongoDB
    client, err := mongo.Connect(context.TODO(), clientOptions)
    if err != nil {
        log.Fatal(err)
    }

    // 检查连接
    err = client.Ping(context.TODO(), nil)
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println("Connected to MongoDB!")

    // 选择数据库和集合
    collection := client.Database("testdb").Collection("people")

    // 构建查询条件和选择字段
    filter := bson.M{"name": "John Doe"}
    projection := bson.M{"_id": 0, "name": 1, "email": 1}

    // 执行查询并获取单个文档
    var result Person
    err = collection.FindOne(context.TODO(), filter, options.FindOne().SetProjection(projection)).Decode(&result)
    if err != nil {
        if err == mongo.ErrNoDocuments {
            fmt.Println("No document found")
        } else {
            log.Fatal(err)
        }
    }

    // 打印结果
    fmt.Printf("Found a single document: %+v\n", result)

    // 断开连接
    err = client.Disconnect(context.TODO())
    if err != nil {
        log.Fatal(err)
    }
    fmt.Println("Connection to MongoDB closed.")
}