使用 sync.Mutex 与 sync.WaitGroup

线程不安全的用法：

{var wg sync.WaitGroupcount := 0for i := 0; i < 10; i++ {// wg add 1 goroutinewg.Add(1)// goroutinego func() {defer wg.Done()for i := 0; i < 10000; i++ {// unsafe incrementcount++}}()}wg.Wait()fmt.Println(count)
}

加锁，线程安全：

{var myLock sync.Mutexvar wg sync.WaitGroupcount := 0for i := 0; i < 10; i++ {// wg add 1 goroutinewg.Add(1)// goroutinego func() {defer wg.Done()for i := 0; i < 10000; i++ {// safe incrementmyLock.Lock()count++myLock.Unlock()}}()}wg.Wait()fmt.Println(count)
}

其中一个运行输出：
53546
100000

自定义一个safe Counter

package counterimport ("log""sync"
)type Counter struct {mu    *sync.MutexValue int
}func NewCounter(value int) *Counter {return &Counter{new(sync.Mutex), 0,}
}func (c *Counter) Increment() {c.mu.Lock()// defer funcdefer func() {c.mu.Unlock()log.Printf("mu sync.Mutex Unlocked!")}()// safe increment Valuec.Value++
}

使用 safe Counter

{var wg sync.WaitGroupcount := counter.NewCounter(0)for i := 0; i < 10; i++ {// wg add 1 goroutinewg.Add(1)// goroutinego func() {defer wg.Done()for i := 0; i < 10000; i++ {// safe incrementcount.Increment()}}()}wg.Wait()fmt.Println(count.Value)
}

正确输出：
100000