Go语学习笔记 - 读写锁 | 从零开始Go语言

学习笔记，写到哪是哪。

读写锁是我们工作中常用的，说白了，可以同时读，但是不能同时写。

样例代码如下

package main

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

var (
	rwCount  int
	myRWLock sync.RWMutex
	wg2      sync.WaitGroup
)

func ReadCount() int {
	myRWLock.RLock()
	fmt.Println("ReadCount readlock ")
	time.Sleep(time.Second)
	defer myRWLock.RUnlock()
	defer fmt.Println("ReadCount unreadlock ")
	return rwCount
}

func ReadCount1() int {
	myRWLock.RLock()
	fmt.Println("ReadCount1 readlock ")
	time.Sleep(time.Second)
	defer myRWLock.RUnlock()
	defer fmt.Println("ReadCount1 unreadlock ")
	return rwCount
}

func HandleCount() {
	myRWLock.Lock()
	fmt.Println("HandleCount writelock ")
	time.Sleep(time.Second)
	defer myRWLock.Unlock()
	defer fmt.Println("HandleCount unwritelock ")
	rwCount += 1
}

func main() {
	wg2.Add(3)
	go func() {
		defer wg2.Done()
		for i := 0; i < 11; i++ {
			fmt.Println("count1 -> ", ReadCount())
		}
	}()
	go func() {
		defer wg2.Done()
		for i := 0; i < 11; i++ {
			fmt.Println("count2 -> ", ReadCount1())
		}
	}()
	go func() {
		defer wg2.Done()
		for i := 0; i < 10; i++ {
			HandleCount()
			fmt.Println("count -> add 1")
		}
	}()
	wg2.Wait()
}

执行结果片段

ReadCount1 readlock 
ReadCount readlock 
ReadCount1 unreadlock 
count2 ->  0
ReadCount unreadlock 
count1 ->  0
HandleCount writelock 
HandleCount unwritelock 
count -> add 1
ReadCount readlock 
ReadCount1 readlock 
ReadCount1 unreadlock 
count2 ->  1
ReadCount unreadlock 
count1 ->  1

注意

1、可以看到两个读数据协程都可以获取到读锁。

2、使用了 sync.WaitGroup进行协程等待。