构造函数

type Person {    name string,    age    int64,    country string,    ...}func NewPerson(name string,age int64,country sting)*Person{      return &Person{ name: name,}

package mainimport (    "fmt")type options struct {    a int64    b string    c map[int]string}func NewOption(opt ...ServerOption) *options {    r := new(options)    for _, o := range opt {        o(r)    }    return r}type ServerOption func(*options)func WriteA(s int64) ServerOption {    return func(o *options) {        o.a = s    }}func WriteB(s string) ServerOption {    return func(o *options) {        o.b = s    }}func WriteC(s map[int]string) ServerOption {    return func(o *options) {        o.c = s    }}func main() {    opt1 := WriteA(int64(1))    opt2 := WriteB("test")    opt3 := WriteC(make(map[int]string,0))    op := NewOption(opt1, opt2, opt3)    fmt.Println(op.a, op.b, op.c)}

func NewServer(addr string, options ...func(*Server)) (*Server, error) {    srv := &Server{    Addr: addr, }    for _, option := range options {       option(srv)    }    return srv} func timeout(d time.Duration) func(*Server) {    return func(srv *Server) {        srv.timeout = d    }} func tls(c *config) func(*Server) {    return func(srv *Server) {        Tls := loadConfig(c)        srv.tls = Tls    }} //使用src, err = NewServer("localhost:8080", timeout(1), tls(path/to/cert))

类工厂模式

// 存放 
       
         对应关系var mux map[string]func(option *Option) error // 注册handlerfunc register(key string, f func(option *Option) error) {    if mux == nil {        mux = make(map[string]func(option *Option) error)    }    if _, exist := mux[key]; exist {        return errors.New("handler exist")    }    mux[key] = f} // factoryfunc factory(option *Option) error {    return mux[option.Key](option)}