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go实现并发安全hashtable 拉链法

article 2024/12/26 11:20:54

在这个实现中，HashTable包含多个bucket，每个bucket都有一个互斥锁来保证并发安全。Put方法用于插入键值对，Get方法用于获取值，Delete方法用于删除键值对。通过哈希函数确定键应该存储在哪个bucket中，然后在对应的bucket中进行操作。这种实现方式可以有效地处理并发访问，确保哈希表在多线程环境下的正确性。

package main

import (
    "sync"
)

type HashTable struct {
    buckets    []*bucket
    bucketSize int
}

type bucket struct {
    mu     sync.Mutex
    items  map[string]interface{}
}

func NewHashTable(bucketSize int) *HashTable {
    buckets := make([]*bucket, bucketSize)
    for i := range buckets {
        buckets[i] = &bucket{
            items: make(map[string]interface{}),
        }
    }
    return &HashTable{
        buckets:    buckets,
        bucketSize: bucketSize,
    }
}

func (ht *HashTable) hash(key string) int {
    hashValue := 0
    for _, char := range key {
        hashValue += int(char)
    }
    return hashValue % ht.bucketSize
}

func (ht *HashTable) Put(key string, value interface{}) {
    bucketIndex := ht.hash(key)
    bucket := ht.buckets[bucketIndex]
    bucket.mu.Lock()
    bucket.items[key] = value
    bucket.mu.Unlock()
}

func (ht *HashTable) Get(key string) (interface{}, bool) {
    bucketIndex := ht.hash(key)
    bucket := ht.buckets[bucketIndex]
    bucket.mu.Lock()
    value, ok := bucket.items[key]
    bucket.mu.Unlock()
    return value, ok
}

func (ht *HashTable) Delete(key string) {
    bucketIndex := ht.hash(key)
    bucket := ht.buckets[bucketIndex]
    bucket.mu.Lock()
    delete(bucket.items, key)
    bucket.mu.Unlock()
}



func main() {
    ht := NewHashTable(10)

    // 并发安全地插入数据
    var wg sync.WaitGroup
    for i := 0; i < 100; i++ {
        wg.Add(1)
        go func(i int) {
            defer wg.Done()
            ht.Put(fmt.Sprintf("key%d", i), i)
        }(i)
    }
    wg.Wait()

    // 并发安全地读取数据
    for i := 0; i < 100; i++ {
        wg.Add(1)
        go func(i int) {
            defer wg.Done()
            value, ok := ht.Get(fmt.Sprintf("key%d", i))
            if ok {
                fmt.Println(value)
            }
        }(i)
    }
    wg.Wait()

    // 并发安全地删除数据
    for i := 0; i < 100; i++ {
        wg.Add(1)
        go func(i int) {
            defer wg.Done()
            ht.Delete(fmt.Sprintf("key%d", i))
        }(i)
    }
    wg.Wait()
}