17.1Go语言操作MongoDB

驱动安装

go get go.mongodb.org/mongo-driver/mongo

基础连接示例


package mainimport ("context""fmt""log""time""go.mongodb.org/mongo-driver/mongo""go.mongodb.org/mongo-driver/mongo/options"
)func main() {// 设置客户端选项clientOptions := options.Client().ApplyURI("mongodb://localhost:27017").SetConnectTimeout(10 * time.Second)// 连接MongoDBclient, err := mongo.Connect(context.Background(), clientOptions)if err != nil {log.Fatal(err)}defer func() {if err = client.Disconnect(context.Background()); err != nil {log.Fatal(err)}}()fmt.Println("成功连接到MongoDB!")
}

标题数据库操作

创建数据库和集合

db := client.Database("mydb")
usersColl := db.Collection("users")

文档定义（结构体）

type User struct {ID       primitive.ObjectID `bson:"_id,omitempty" json:"id"`Username string             `bson:"username" json:"username"`Email    string             `bson:"email" json:"email"`CreatedAt time.Time        `bson:"createdAt" json:"created_at"`
}

CRUD操作

插入文档

insertResult, err := usersColl.InsertOne(context.Background(),User{Username: "john_doe",Email:    "john@example.com",CreatedAt: time.Now(),},
)if err != nil {log.Fatal(err)
}fmt.Printf("插入ID: %v\n", insertResult.InsertedID)

查询文档

filter := bson.D{{"username", "john_doe"}}
var results []Usercursor, err := usersColl.Find(context.Background(), filter)
if err != nil {log.Fatal(err)
}defer cursor.Close(context.Background())if err = cursor.All(context.Background(), &results); err != nil {log.Fatal(err)
}fmt.Printf("找到%d个用户:\n", len(results))
for _, user := range results {fmt.Printf("- %s (%s)\n", user.Username, user.Email)
}

更新文档


updateFilter := bson.D{{"username", "john_doe"}}
update := bson.D{{"$set", bson.D{{"email", "john_new@example.com"}}}}result, err := usersColl.UpdateOne(context.Background(),updateFilter,update,
)if err != nil {log.Fatal(err)
}fmt.Printf("匹配到%d个文档，更新%d个\n", result.MatchedCount, result.UpdatedCount)

删除文档


deleteResult, err := usersColl.DeleteOne(context.Background(),bson.D{{"username", "john_doe"}},
)if err != nil {log.Fatal(err)
}fmt.Printf("删除%d个文档\n", deleteResult.DeletedCount)

聚合操作

pipeline := mongo.Pipeline{{{"$match", bson.D{{"status", "active"}}}},{{"$group", bson.D{{"_id", bson.D{{"department", "$department"}}},{"total", bson.D{{"$sum", 1}}},}}},
}var results []bson.M
cursor, err := usersColl.Aggregate(context.Background(), pipeline)
if err != nil {log.Fatal(err)
}defer cursor.Close(context.Background())if err = cursor.All(context.Background(), &results); err != nil {log.Fatal(err)
}fmt.Println("部门用户统计:")
for _, doc := range results {fmt.Printf("%s: %d人\n", doc["_id"].(string), doc["total"].(int32))
}

事务处理

session, err := client.StartSession()
if err != nil {log.Fatal(err)
}
defer session.EndSession(context.Background())txOptions := options.Transaction().SetReadConcern(readconcern.Majority()).SetWriteConcern(writeconcern.Majority())err = session.WithTransaction(context.Background(), func(sessCtx mongo.SessionContext) error {// 在事务中执行多个操作_, err := usersColl.InsertOne(sessCtx, User{Username: "alice"})if err != nil {return err}_, err = ordersColl.InsertOne(sessCtx, Order{UserID: "alice", Total: 100})if err != nil {return err}return nil
}, txOptions)if err != nil {log.Fatal("事务失败:", err)
} else {fmt.Println("事务成功")
}

高级功能

索引管理


indexModel := mongo.IndexModel{Keys: bson.D{{"username", 1}},
}_, err = usersColl.Indexes().CreateOne(context.Background(),indexModel,
)if err != nil {log.Fatal(err)
}
fmt.Println("索引创建成功")

分页查询


pageSize := 10
pageNumber := 2filter := bson.D{}
sort := bson.D{{"createdAt", -1}}optionsFind := options.Find().SetLimit(int64(pageSize)).SetSkip(int64((pageNumber-1)*pageSize)).SetSort(sort)cursor, err := usersColl.Find(context.Background(), filter, optionsFind)
// 处理游标...

错误处理

func safeMongoOp(ctx context.Context, op func() (interface{}, error)) (interface{}, error) {ctx, cancel := context.WithTimeout(ctx, 5*time.Second)defer cancel()result, err := op()if err != nil {return nil, fmt.Errorf("mongo operation failed: %w", err)}return result, nil
}

连接池配置

clientOptions := options.Client().ApplyURI("mongodb://localhost:27017").SetMaxPoolSize(100).SetMinPoolSize(10).SetConnectTimeout(10 * time.Second).SetSocketTimeout(30 * time.Second)

资源清理


// 使用defer确保资源释放
cursor, err := collection.Find(ctx, filter)
if err != nil {// 处理错误
}defer cursor.Close(ctx)

性能优化建议

使用批量操作（InsertMany/UpdateMany）
合理使用索引
限制查询结果集大小
使用投影（Projection）减少数据传输
适当使用缓存机制

测试

setupTestDB(t)// 测试插入user := User{Username: "test_user"}insertResult, _ := collection.InsertOne(context.Background(), user)// 测试查询filter := bson.D{{"username", "test_user"}}var foundUser Usererr := collection.FindOne(context.Background(), filter).Decode(&foundUser)// 清理测试数据_, _ = collection.DeleteOne(context.Background(), bson.D{{"_id", insertResult.InsertedID}})

简单完整例子

package main import ("context""fmt""log""time""go.mongodb.org/mongo-driver/bson" "go.mongodb.org/mongo-driver/mongo" "go.mongodb.org/mongo-driver/mongo/options" 
)
// 定义数据结构体 
type User struct {Name  string `bson:"name"`Email string `bson:"email"`Age   int    `bson:"age"`
}func main() {// 1. 连接 MongoDB client, err := mongo.Connect(context.TODO(),options.Client().ApplyURI("mongodb://localhost:27017"),)if err != nil {log.Fatal("连接失败:", err)}defer client.Disconnect(context.TODO()) // 确保关闭连接 // 2. 选择数据库和集合 db := client.Database("testdb")collection := db.Collection("users")// 3. 插入文档 user := User{Name: "张三", Email: "zhangsan@example.com",  Age: 28}insertResult, err := collection.InsertOne(context.TODO(), user)if err != nil {log.Fatal("插入失败:", err)}fmt.Printf("插入ID: %v\n", insertResult.InsertedID)// 4. 查询文档 filter := bson.D{{"name", "张三"}}var result User err = collection.FindOne(context.TODO(), filter).Decode(&result)if err != nil {log.Fatal("查询失败:", err)}fmt.Printf("查询结果: %+v\n", result)// 5. 更新文档 update := bson.D{{"$set", bson.D{{"age", 30}}}}updateResult, err := collection.UpdateOne(context.TODO(),filter,update,)if err != nil {log.Fatal("更新失败:", err)}fmt.Printf("更新数量: %d\n", updateResult.ModifiedCount)// 6. 删除文档 deleteResult, err := collection.DeleteOne(context.TODO(), filter)if err != nil {log.Fatal("删除失败:", err)}fmt.Printf("删除数量: %d\n", deleteResult.DeletedCount)
}```