Golang实现一个简单的Cache存储器

[dongjun111111]

Golang实现一个简单的Cache存储器

前几天在网上浏览的时候看到别人用Golang实现了一个有Cache功能的Demo,特地自己测试学习了一下，代码如下：

package main

import (
    "errors"
    "fmt"
    "time"
)

type object struct {
    time    time.Time
    timeout time.Duration
    obj     interface{}
}

type cachetable map[string]*object

var (
    cache            cachetable
    ErrTimeOut       error = errors.New("The cache has been timeout.")
    ErrKeyNotFound   error = errors.New("The key was not found.")
    ErrTypeAssertion error = errors.New("Type assertion error.")
)

func init() {
    cache = make(cachetable, 1000)
    go gc()
}

func gc() {
    for {
        for k, v := range cache {
            if v.time.Add(v.timeout).Before(time.Now()) {
                delete(cache, k)
            }
            time.Sleep(time.Microsecond)
        }
        time.Sleep(time.Second)
    }
}

func Set(key string, obj interface{}, timeout time.Duration) {
    cache[key] = &object{time.Now(), timeout, obj}
}

func Get(key string) (obj interface{}, err error) {
    c, ok := cache[key]
    if ok {
        now := time.Now()
        if c.time.Add(c.timeout).After(now) {
            c.time = now
            return c.obj, nil
        }
        delete(cache, key)
        return nil, ErrTimeOut
    }
    return nil, ErrKeyNotFound
}

func Delete(key string) {
    delete(cache, key)
}

func HasKey(key string) bool {
    _, ok := cache[key]
    return ok
}

func main() {
    test := "test"
    Set("test", test, time.Duration(10*time.Second))
    obj, err := Get("test")
    if err != nil {
        fmt.Println(err)
    } else {
        fmt.Println("The first result is :", obj)
    }
    type p struct {
        a, b, c, d, e int
    }
    struct2 := p{56, 7, 8, 9, 9}
    Set("name", struct2, time.Duration(10*time.Second))
    resultstruct2, err2 := Get("name")
    if err != nil {
        fmt.Println(err2)
    } else {
        fmt.Println("The second result is :", resultstruct2)
    }
    Delete("name")
    resultstruct3, _ := Get("name")
    if resultstruct3 == nil {
        fmt.Println("Delete was success")
    } else {
        fmt.Println("Delete was error")
    }

    isornot := HasKey("test")
    if isornot {
        fmt.Println("test exsited is true")
    } else {
        fmt.Println("test exsited is false")
    }
    isornot2 := HasKey("name")
    if isornot2 {
        fmt.Println("name exsited is true")
    } else {
        fmt.Println("name exsited is false")
    }

}

结果是：

The first result is : test
The second result is : {56 7 8 9 9}
Delete was success
test exsited is true
name exsited is false