golang继承

避免空指针

避免结构体 B 在使用 A 创建的连接时出现空指针错误。

初始化检查

type A struct {
	MySQL     *sql.DB
	InfluxDB  *influxdb.Client
	OpenSearch *opensearch.Client
}

func (a *A) Init() error {
	// 初始化 MySQL
	var err error
	a.MySQL, err = sql.Open("mysql", "user:password@/dbname")
	if err != nil {
		return err
	}

	// 初始化 InfluxDB
	a.InfluxDB, err = influxdb.NewClient(influxdb.Options{
		Addr: "http://localhost:8086",
	})
	if err != nil {
		return err
	}

	// 初始化 OpenSearch
	a.OpenSearch, err = opensearch.NewClient(opensearch.Config{
		Addresses: []string{"http://localhost:9200"},
	})
	if err != nil {
		return err
	}

	return nil
}

type B struct {
	A *A
}

func (b *B) UseConnections() {
	if b.A.MySQL == nil || b.A.InfluxDB == nil || b.A.OpenSearch == nil {
		log.Fatal("Connections are not initialized")
	}

	// 使用 MySQL, InfluxDB, OpenSearch
}

依赖注入

type A struct {
	MySQL     *sql.DB
	InfluxDB  *influxdb.Client
	OpenSearch *opensearch.Client
}

func (a *A) Init() error {
	// 初始化 MySQL
	var err error
	a.MySQL, err = sql.Open("mysql", "user:password@/dbname")
	if err != nil {
		return err
	}

	// 初始化 InfluxDB
	a.InfluxDB, err = influxdb.NewClient(influxdb.Options{
		Addr: "http://localhost:8086",
	})
	if err != nil {
		return err
	}

	// 初始化 OpenSearch
	a.OpenSearch, err = opensearch.NewClient(opensearch.Config{
		Addresses: []string{"http://localhost:9200"},
	})
	if err != nil {
		return err
	}

	return nil
}

type B struct {
	MySQL     *sql.DB
	InfluxDB  *influxdb.Client
	OpenSearch *opensearch.Client
}

func NewB(a *A) *B {
	return &B{
		MySQL:     a.MySQL,
		InfluxDB:  a.InfluxDB,
		OpenSearch: a.OpenSearch,
	}
}

func (b *B) UseConnections() {
	// 使用 MySQL, InfluxDB, OpenSearch
}

懒加载

type A struct {
	MySQL     *sql.DB
	InfluxDB  *influxdb.Client
	OpenSearch *opensearch.Client
}

func (a *A) Init() error {
	// 初始化 MySQL
	var err error
	a.MySQL, err = sql.Open("mysql", "user:password@/dbname")
	if err != nil {
		return err
	}

	// 初始化 InfluxDB
	a.InfluxDB, err = influxdb.NewClient(influxdb.Options{
		Addr: "http://localhost:8086",
	})
	if err != nil {
		return err
	}

	// 初始化 OpenSearch
	a.OpenSearch, err = opensearch.NewClient(opensearch.Config{
		Addresses: []string{"http://localhost:9200"},
	})
	if err != nil {
		return err
	}

	return nil
}

type B struct {
	A *A
}

func (b *B) UseConnections() error {
	if b.A.MySQL == nil || b.A.InfluxDB == nil || b.A.OpenSearch == nil {
		err := b.A.Init()
		if err != nil {
			return err
		}
	}

	// 使用 MySQL, InfluxDB, OpenSearch
	return nil
}