要点：
-
sync.Once 的应用
-
高并发场景下读写锁
package singleton
import "sync"
var (
p *Pet
once sync.Once
)
func init(){
once.Do(
func() {
p = &Pet{}
})
}
func GetInstance() *Pet{
return p
}
type Pet struct {
Name string
Age int
m sync.Mutex
}
func (p *Pet)GetName()string{
return p.Name
}
func (p *Pet) GetAge() int{
return p.Age
}
func(p *Pet) SetName(name string) {
p.m.Lock()
defer p.m.Unlock()
p.Name = name
}
func(p *Pet) IncAge() {
p.m.Lock()
defer p.m.Unlock()
p.Age++
}
测试用例
package singleton
import "testing"
func TestGetInstance(t *testing.T) {
p := GetInstance()
p.SetName("tommy")
p.IncAge()
p.GetName()
p.GetAge()
}
测试并发场景
func IncAgeTest1(){
p = GetInstance()
p.IncAge()
}
func IncAgeTest2(){
p = GetInstance()
p.IncAge()
}
package singleton
import (
"fmt"
"sync"
"testing"
)
func TestGetInstance(t *testing.T) {
wg := sync.WaitGroup{}
wg.Add(200)
for i:=0;i<100;i++{
go func() {
defer wg.Done()
IncAgeTest1()
}()
go func() {
defer wg.Done()
IncAgeTest2()
}()
}
wg.Wait()
p := GetInstance()
fmt.Println(p.Age)
}
// output === RUN TestGetInstance 200
