go操作mongodb

示例

package main

import (
	"context"
	"fmt"
	"log"
	"time"

	"go.mongodb.org/mongo-driver/bson"
	"go.mongodb.org/mongo-driver/bson/primitive"
	"go.mongodb.org/mongo-driver/mongo"
	"go.mongodb.org/mongo-driver/mongo/options"
)

// User 结构体，对应 MongoDB 中的文档
type User struct {
	ID       primitive.ObjectID `bson:"_id,omitempty"`
	Name     string             `bson:"name"`
	Email    string             `bson:"email"`
	Age      int                `bson:"age,omitempty"`
	Active   bool               `bson:"active,omitempty"`
	LastSeen time.Time          `bson:"last_seen,omitempty"`
}

func connect() (*mongo.Client, context.Context, context.CancelFunc) {
	// 设置上下文，超时 10 秒
	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)

	// MongoDB 连接 URI（根据你的配置修改）
	uri := "mongodb://localhost:27017" // 本地
	// uri := "mongodb://user:pass@host:port/db" // 远程或带认证

	// 创建 MongoDB 客户端
	client, err := mongo.Connect(ctx, options.Client().ApplyURI(uri))
	if err != nil {
		log.Fatal("Failed to connect to MongoDB:", err)
	}

	// 测试连接
	err = client.Ping(ctx, nil)
	if err != nil {
		log.Fatal("Failed to ping MongoDB:", err)
	}

	fmt.Println("Connected to MongoDB!")
	return client, ctx, cancel
}
func insertUser(client *mongo.Client, ctx context.Context) {
	collection := client.Database("testdb").Collection("users")

	user := User{
		Name:     "Alice",
		Email:    "alice@example.com",
		Age:      28,
		Active:   true,
		LastSeen: time.Now(),
	}

	result, err := collection.InsertOne(ctx, user)
	if err != nil {
		log.Fatal("Insert failed:", err)
	}

	fmt.Printf("Inserted user with ID: %s\n", result.InsertedID)
}
func findUserByID(client *mongo.Client, ctx context.Context, idStr string) {
	collection := client.Database("testdb").Collection("users")

	// 将字符串 ID 转换为 ObjectID
	objectID, err := primitive.ObjectIDFromHex(idStr)
	if err != nil {
		log.Fatal("Invalid ID format:", err)
	}

	var user User
	// 查询
	err = collection.FindOne(ctx, bson.M{"_id": objectID}).Decode(&user)
	if err != nil {
		if err == mongo.ErrNoDocuments {
			fmt.Printf("❌ 未找到 ID 为 %s 的用户\n", idStr)
		} else {
			log.Fatal("查询出错:", err)
		}
		return
	}

	fmt.Printf("✅ 查询到用户: %+v\n", user)
}
func findUsers(client *mongo.Client, ctx context.Context) {
	collection := client.Database("testdb").Collection("users")

	// 查询所有用户
	cursor, err := collection.Find(ctx, bson.M{})
	if err != nil {
		log.Fatal("Find failed:", err)
	}
	defer cursor.Close(ctx)

	fmt.Println("All users:")
	for cursor.Next(ctx) {
		var user User
		if err := cursor.Decode(&user); err != nil {
			log.Fatal("Decode error:", err)
		}
		fmt.Printf("User: %+v\n", user)
	}

	if err := cursor.Err(); err != nil {
		log.Fatal("Cursor error:", err)
	}
}
func findUserByName(client *mongo.Client, ctx context.Context, name string) {
	collection := client.Database("testdb").Collection("users")

	var user User
	err := collection.FindOne(ctx, bson.M{"name": name}).Decode(&user)
	if err != nil {
		if err == mongo.ErrNoDocuments {
			fmt.Printf("User '%s' not found\n", name)
		} else {
			log.Fatal("Query error:", err)
		}
		return
	}

	fmt.Printf("Found user: %+v\n", user)
}
func updateUser(client *mongo.Client, ctx context.Context, name string) {
	collection := client.Database("testdb").Collection("users")

	update := bson.M{
		"$set": bson.M{
			"age":       29,
			"active":    false,
			"last_seen": time.Now(),
		},
	}

	result, err := collection.UpdateOne(ctx, bson.M{"name": name}, update)
	if err != nil {
		log.Fatal("Update failed:", err)
	}

	fmt.Printf("Modified %v document(s)\n", result.ModifiedCount)
}
func deleteUser(client *mongo.Client, ctx context.Context, name string) {
	collection := client.Database("testdb").Collection("users")

	result, err := collection.DeleteOne(ctx, bson.M{"name": name})
	if err != nil {
		log.Fatal("Delete failed:", err)
	}

	fmt.Printf("Deleted %v document(s)\n", result.DeletedCount)
}
func main() {
	client, ctx, cancel := connect()
	defer cancel()
	defer func() {
		if err := client.Disconnect(ctx); err != nil {
			log.Fatal("Failed to disconnect:", err)
		}
	}()

	// 执行 CRUD 操作
	insertUser(client, ctx)
	// 替换为实际存在的 _id（12字节或 24位十六进制字符串）
	idStr := "670b123456789abcde123456" // 示例 ID
	findUserByID(client, ctx, idStr)
	findUsers(client, ctx)
	findUserByName(client, ctx, "Alice")
	updateUser(client, ctx, "Alice")
	findUsers(client, ctx)
	deleteUser(client, ctx, "Alice")
	findUsers(client, ctx) // 再次查询，确认已删除
}