使用懒惰模式的单例模式，使用双重检查加锁保证线程安全
singleton.go
package singleton
import "sync"
//Singleton 是单例模式类
type Singleton struct{}
var singleton *Singleton
var once sync.Once
//GetInstance 用于获取单例模式对象
func GetInstance() *Singleton {
once.Do(func() {
singleton = &Singleton{}
})
return singleton
}
singleton_test.go
package singleton
import (
"sync"
"testing"
)
const parCount = 100
func TestSingleton(t *testing.T) {
ins1 := GetInstance()
ins2 := GetInstance()
if ins1 != ins2 {
t.Fatal("instance is not equal")
}
}
func TestParallelSingleton(t *testing.T) {
wg := sync.WaitGroup{}
wg.Add(parCount)
instances := [parCount]*Singleton{}
for i := 0; i < parCount; i++ {
go func(index int) {
instances[index] = GetInstance()
wg.Done()
}(i)
}
wg.Wait()
for i := 1; i < parCount; i++ {
if instances[i] != instances[i-1] {
t.Fatal("instance is not equal")
}
}
}