> ### 第五例 并發安全字典 * 自制并發安全字典 ~~~ package main import ( "sync" "fmt" ) // 一個自制的簡易并發安全字典 type CustomMap struct { m map[interface{}]interface{} mu sync.RWMutex } //TODO : 初始化 func NewCustomMap() *CustomMap { return &CustomMap{ m: make(map[interface{}]interface{}), } } //TODO: 根據鍵獲取值 func (cm *CustomMap) Load(key interface{}) (value interface{}, ok bool) { cm.mu.Lock() value, ok = cm.m[key] cm.mu.Unlock() return } //TODO : 添加鍵值 func (cm *CustomMap) Store(key, value interface{}) { cm.mu.Lock() cm.m[key] = value cm.mu.Unlock() } //TODO : 修改鍵值 func (cm *CustomMap) LoadOrStore(key, value interface{}) (actual interface{}, loaded bool) { cm.mu.Lock() actual, loaded = cm.m[key] if !loaded { return } cm.m[key] = value cm.mu.Unlock() return value, true } //TODO : 刪除鍵值 func (cm *CustomMap) Delete(key interface{}) { cm.mu.Lock() delete(cm.m, key) cm.mu.Unlock() } //TODO : 遍歷鍵值 func (cm *CustomMap) Range(f func(key, value interface{}) bool) { cm.mu.RLock() for k, v := range cm.m { f(k, v) } cm.mu.RUnlock() } func main() { cm := NewCustomMap() s := []struct { k int v string }{ {1, "a"}, {2, "b"}, {3, "c"}, } //添加鍵值 for k, v := range s { cm.Store(k, v) } //遍歷 cm.Range(func(k, v interface{}) bool { fmt.Println(k, v) return true }) } ~~~ * 官方并發安全字典 ~~~ package main import ( "sync" "fmt" ) func main() { //Go言語官方是在Go 1.9中才正式加入了并發安全的字典類型sync.Map //在自制并發安全字典時,方法名和功能是參照官方寫的(官方的是原子操作) //cm := NewCustomMap() cm := sync.Map{} s := []struct { k int v string }{ {1, "a"}, {2, "b"}, {3, "c"}, } //添加鍵值 for k, v := range s { cm.Store(k, v) } //遍歷 cm.Range(func(k, v interface{}) bool { fmt.Println(k, v) return true }) } ~~~