golang并发单例模式实现

package main

import (
    "fmt"
    "sync"
    "time"
)

var _self *Singleton

type Singleton struct {
    Name string
    sync.Once
}

func NewInstance(name string) *Singleton {
    fmt.Println("Create instance", name)
    time.Sleep(4 * time.Second)
    _self.Name = name
    return _self
}

func Instance(name string) *Singleton {
    if _self.Name == "" {
        _self.Once.Do(func() { NewInstance(name) })
    }
    return _self
}

func main() {
    _self = new(Singleton)
    _self.Once = sync.Once{}
    go Instance("cyeam")
    go Instance("bryce")
    time.Sleep(10 * time.Second)
    fmt.Println(_self.Name)
}
运行看一下就知道了