golang的Map讀寫鎖

package main

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

type ConcurMap struct {
    Data map[string]int
    Lock *sync.RWMutex
}

func NewConcurMap()  *ConcurMap{
    return &ConcurMap{
        Data: make(map[string]int),
        Lock:&sync.RWMutex{},
    }
}

func (d ConcurMap) Get(k string) int{

    d.Lock.RLock()

    defer d.Lock.RUnlock()

    return d.Data[k]

}

func (d ConcurMap) Set(k string,v int) {

    d.Lock.Lock()

    defer d.Lock.Unlock()

    d.Data[k]=v

}

func main(){
    c := NewConcurMap()
    go func() {//開一個協程寫map
        for j := 0; j < 1000000; j++ {
            c.Set(fmt.Sprintf("%d", j),j)
        }
    }()
    go func() {    //開一個協程讀map
        for j := 0; j < 1000000; j++ {
            fmt.Println(c.Get(fmt.Sprintf("%d",j)))
        }
    }()

    time.Sleep(time.Second*20)

}      

ConcurMap 定義的讀寫鎖需要時指針類型，否則不會有預期的效果。

一定要将該鎖定義為指針類型

對map統計

/ Count 統計key個數
func (m MutexMap) Count() int {
    m.mu.RLock() // 加鎖(讀鎖定)
    count := len(m.items)
    m.mu.RUnlock() // 解鎖
    return count
}      

// Keys 所有的key
func (m MutexMap) Keys() []string {
    m.mu.RLock() // 加鎖(讀鎖定)
    keys := make([]string, len(m.items))
    for k := range m.items {
        keys = append(keys, k)
    }
    m.mu.RUnlock() // 解鎖
 
    return keys
    }