//多个线程同时运行，获得Mutex锁者线程优先执行，其余线程阻塞等待
func testMutex() {mutex := sync.Mutex{};for i := 0; i < 10; i++ {go func(idx int) {mutex.Lock();defer mutex.Unlock();fmt.Println("idx :=", idx);time.Sleep(time.Second);}(i)}time.Sleep(20 * time.Second);fmt.Println("Func finish.");
}

//写请求在读锁和写锁时都必须阻塞等待，读请求只在写锁时阻塞等待
func testRWMutex() {rwMutex := sync.RWMutex{};for i := 0; i < 10; i++ {go func(idx int) {rwMutex.RLock();defer rwMutex.RUnlock();fmt.Println("Read Mutex :",idx);}(i);go func(idx int) {rwMutex.Lock();defer rwMutex.Unlock();fmt.Println("Write Mutex :",idx);time.Sleep(time.Second);}(i);}time.Sleep(20 * time.Second);fmt.Println("Func finish.");
}

func testCond() {cond := sync.NewCond(&sync.Mutex{});cond.L.Lock(); //①上锁
    defer cond.L.Unlock();go func() {fmt.Println("go wait lock.");cond.L.Lock(); //②等Wait解锁
defer cond.L.Unlock(); //⑤解锁后触发Waitdefer fmt.Println("go unlock.");fmt.Println("go locked.");cond.Signal(); //④触发Wait等待解锁
    }()time.Sleep(time.Second);fmt.Println("start wait.");for {cond.Wait(); //③可以理解为立刻解锁并触发一个阻塞线程（如果没有阻塞线程则不触发）后立刻再上锁等待Signal信号fmt.Println("wait finish.");break;}time.Sleep(time.Second);fmt.Println("Func finish.");
}

//Add 增加等待计数;Done减少等待计数；当计数为0时触发Wait;
func testWaitGroup() {waitGroup := sync.WaitGroup{};for i := 0; i < 10; i++ {waitGroup.Add(1);go func(idx int) {time.Sleep(time.Second);fmt.Println("go : ", idx);waitGroup.Done();}(i)}for{fmt.Println("start wait.");waitGroup.Wait();fmt.Println("wait finish.");break;}time.Sleep(time.Second);fmt.Println("Func finish.");
}

//只执行一次以后不再触发
func testOnce() {once := sync.Once{};for i := 0; i < 10; i++ {go func(idx int) {once.Do(func() {fmt.Println("Do once : ", idx); //这里只执行一次
            })fmt.Println("go : ", idx);}(i)}time.Sleep(5 * time.Second);fmt.Println("Func finish.");
}

func testMap() {syncMap := sync.Map{};for i := 0; i < 10; i++ {go func(idx int) {//如果没有则保存起来_, ok := syncMap.LoadOrStore(idx, " StrVal = "+strconv.FormatInt(int64(idx), 10));if !ok {fmt.Println("Store idx = ",idx);}}(i)go func(idx int) {val, ok := syncMap.Load(idx);if ok {fmt.Println("Load success idx = ", idx, val);} else {fmt.Println("Load fail idx = ", idx)}}(i)}time.Sleep(5 * time.Second);fmt.Println("Func finish.");
}

func testPool() {p := &sync.Pool{New: func() interface{} {return -1;},}for i := 0; i < 10; i++ {go func(idx int) {p.Put(idx);}(i)}//取出来的对象是无序的for i := 0; i < 20; i++ {go func() {val := p.Get();fmt.Println("Get val = ", val);}()}time.Sleep(5 * time.Second);fmt.Println("Func finish.");
}

func testPoolPutGet(){myPool := &sync.Pool{New: func() interface{} {return 0;},}myPool.Put(1) //放入1myPool.Put(2) //放入2
time.Sleep(time.Second)p1 := myPool.Get().(int)fmt.Println(p1) // 获得2
p2 := myPool.Get().(int)fmt.Println(p2) // 获得0，而不是1！
}