56 lines
872 B
Go
56 lines
872 B
Go
package main
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import (
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"fmt"
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"sync"
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"time"
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)
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type Cache struct {
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mu sync.RWMutex
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data map[string]string
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}
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func (c *Cache) Get(key string) string {
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c.mu.RLock()
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defer c.mu.RUnlock()
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return c.data[key]
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}
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func (c *Cache) Set(key, value string) {
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c.mu.Lock()
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defer c.mu.Unlock()
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c.data[key] = value
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}
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func main() {
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c := &Cache{data: make(map[string]string)}
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c.Set("foo", "bar")
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var wg sync.WaitGroup
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// 多个读 goroutine
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for i := 0; i < 5; i++ {
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wg.Add(1)
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go func(id int) {
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defer wg.Done()
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for j := 0; j < 5; j++ {
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v := c.Get("foo")
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fmt.Printf("reader-%d 第 %d 次读到: %s\n", id, j, v)
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time.Sleep(100 * time.Millisecond)
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}
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}(i)
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}
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// 一个写 goroutine
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wg.Add(1)
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go func() {
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defer wg.Done()
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time.Sleep(300 * time.Millisecond)
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fmt.Println("writer: 更新 foo -> baz")
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c.Set("foo", "baz")
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}()
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wg.Wait()
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}
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