golang 简单全局计数器实现
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package main
import (
"fmt"
"sync"
)
type single struct {
mu sync.Mutex
values map[string]int64
}
var counters = single{
values: make(map[string]int64),
}
func (s *single) Get(key string) int64 {
s.mu.Lock()
defer s.mu.Unlock()
return s.values[key]
}
func (s *single) Incr(key string) int64 {
s.mu.Lock()
defer s.mu.Unlock()
s.values[key]++
return s.values[key]
}
func main() {
fmt.Println(counters.Incr("bar"))
fmt.Println(counters.Incr("bar"))
fmt.Println(counters.Incr("bar"))
fmt.Println(counters.Get("foo"))
fmt.Println(counters.Get("bar"))
}