1.方法代码：

func randStr(num int) string{
    maps := "abcdefghijklmnopqrstuvwxyz0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    rand.Seed(time.Now().Unix())
    res := []byte{}
    for i := 0 ; i < num ; i ++ {
        res = append(res,maps[rand.Intn(len(maps))])
    }
    return string(res)
}

2.示例代码：

func main(){
    fmt.Println(randStr(10))
}