局域网电脑管理中的JavaScript哈希表算法实践

// 局域网电脑管理设备信息哈希表类
class LanDeviceHashTable {
  constructor(capacity = 16) {
    this.capacity = capacity; // 哈希表初始容量
    this.size = 0; // 实际存储的设备数量
    this.buckets = new Array(capacity).fill(null).map(() => []); // 桶数组，每个元素为链表
  }
  // 哈希函数：MAC地址转换为索引
  hashFunction(macAddress) {
    // 去除MAC地址中的冒号，转换为十六进制数值
    const macWithoutColon = macAddress.replace(/:/g, '');
    const hexValue = parseInt(macWithoutColon, 16);
    // 取模得到索引，确保在桶数组范围内
    return hexValue % this.capacity;
  }
  // 插入设备信息（局域网电脑管理核心功能）
  insert(macAddress, deviceInfo) {
    const index = this.hashFunction(macAddress);
    const bucket = this.buckets[index];
    // 检查该设备是否已存在，存在则更新信息
    const existingDevice = bucket.find(item => item.key === macAddress);
    if (existingDevice) {
      existingDevice.value = deviceInfo;
    } else {
      bucket.push({ key: macAddress, value: deviceInfo });
      this.size++;
      // 负载因子超过0.7时扩容，保证查询效率
      if (this.size / this.capacity > 0.7) {
        this.resize();
      }
    }
  }
  // 查询设备信息（局域网电脑管理核心功能）
  get(macAddress) {
    const index = this.hashFunction(macAddress);
    const bucket = this.buckets[index];
    const device = bucket.find(item => item.key === macAddress);
    return device ? device.value : null;
  }
  // 删除设备信息
  delete(macAddress) {
    const index = this.hashFunction(macAddress);
    const bucket = this.buckets[index];
    const initialLength = bucket.length;
    this.buckets[index] = bucket.filter(item => item.key !== macAddress);
    if (this.buckets[index].length !== initialLength) {
      this.size--;
      return true;
    }
    return false;
  }
  // 遍历所有设备信息
  traverse(callback) {
    this.buckets.forEach(bucket => {
      bucket.forEach(item => {
        callback(item.key, item.value);
      });
    });
  }
  // 哈希表扩容
  resize() {
    const oldBuckets = this.buckets;
    this.capacity *= 2;
    this.buckets = new Array(this.capacity).fill(null).map(() => []);
    this.size = 0;
    // 重新插入所有设备信息
    oldBuckets.forEach(bucket => {
      bucket.forEach(item => {
        this.insert(item.key, item.value);
      });
    });
  }
}
// 示例：局域网电脑管理系统中使用哈希表
const lanManager = new LanDeviceHashTable();
// 1. 插入局域网设备信息
lanManager.insert('00:1A:2B:3C:4D:5E', {
  deviceName: '办公电脑-01',
  ipAddress: '192.168.1.101',
  onlineStatus: true,
  cpuUsage: 32,
  lastActiveTime: new Date().toLocaleString()
});
lanManager.insert('00:1A:2B:3C:4D:5F', {
  deviceName: '服务器-01',
  ipAddress: '192.168.1.201',
  onlineStatus: true,
  cpuUsage: 45,
  lastActiveTime: new Date().toLocaleString()
});
lanManager.insert('00:1A:2B:3C:4D:60', {
  deviceName: '打印机-01',
  ipAddress: '192.168.1.151',
  onlineStatus: false,
  cpuUsage: 0,
  lastActiveTime: '2025-12-12 08:30:00'
});
// 2. 查询指定设备信息
const serverInfo = lanManager.get('00:1A:2B:3C:4D:5F');
console.log('服务器设备信息：', serverInfo);
// 3. 更新设备在线状态
const printerInfo = lanManager.get('00:1A:2B:3C:4D:60');
if (printerInfo) {
  printerInfo.onlineStatus = true;
  printerInfo.lastActiveTime = new Date().toLocaleString();
  lanManager.insert('00:1A:2B:3C:4D:60', printerInfo);
}
// 4. 遍历所有设备，统计在线设备数量
let onlineCount = 0;
console.log('\n局域网所有设备信息：');
lanManager.traverse((mac, info) => {
  console.log(`MAC: ${mac}, 设备名: ${info.deviceName}, 状态: ${info.onlineStatus ? '在线' : '离线'}`);
  if (info.onlineStatus) onlineCount++;
});
console.log(`\n局域网在线设备数量：${onlineCount} 台`);
// 5. 删除已下线设备（示例）
lanManager.delete('00:1A:2B:3C:4D:60');
console.log('\n删除打印机后在线设备数量：', lanManager.size);