golang实现内存缓存

package main

import (
    "fmt"
    "time"
)

type Cache struct {
    data     map[string]interface{}
    ttl      int64 //过期时间
    interval int64 //清理间隔
}

func NewCache(ttl int64, interval int64) *Cache {
    c := &Cache{
        data:     make(map[string]interface{}),
        ttl:      ttl,
        interval: interval,
    }

    go c.clean()
    return c
}

// 设置数据
func (c *Cache) Set(key string, val interface{}) {
    c.data[key] = val
}

// 获取数据
func (c *Cache) Get(key string) (interface{}, bool) {
    val, ok := c.data[key]
    if !ok {
        return nil, false
    }

    // 判断数据是否过期
    if time.Now().UnixNano() > val.(int64) {
        delete(c.data, key)
        return nil, false
    }

    return val, true
}

// 清理过期数据
func (c *Cache) clean() {
    for range time.Tick(time.Duration(c.interval) * time.Second) {
        for k, v := range c.data {
            if time.Now().UnixNano() > v.(int64) {
                delete(c.data, k)
            }
        }
    }
}

func main() {
    cache := NewCache(10, 5)

    cache.Set("foo", "bar")
    cache.Set("hello", "world")

    val, ok := cache.Get("foo")
    if ok {
        fmt.Println(val) // 输出 bar
    }

    time.Sleep(11 * time.Second)

    _, ok = cache.Get("foo")
    if !ok {
        fmt.Println("key has deleted") // 输出 key has deleted
    }
}