如何利用PHP开发记账系统的数据分片存储功能 - 提供分片存储功能的开发指南

<?php
class ShardingStorage {

   private $servers = array(
      array('host' => 'server1', 'port' => '3306'),
      array('host' => 'server2', 'port' => '3306'),
      array('host' => 'server3', 'port' => '3306')
   );

   private function getServer($key) {
      $num = count($this->servers);
      $index = crc32($key) % $num;
      return $this->servers[$index];
   }

   public function saveData($key, $value) {
      $server = $this->getServer($key);
      // 连接服务器并保存数据
      $conn = new mysqli($server['host'], 'username', 'password', 'database', $server['port']);
      $sql = "INSERT INTO table (key, value) VALUES ('$key', '$value')";
      $conn->query($sql);
      $conn->close();
   }

   public function getData($key) {
      $server = $this->getServer($key);
      // 连接服务器并查询数据
      $conn = new mysqli($server['host'], 'username', 'password', 'database', $server['port']);
      $sql = "SELECT value FROM table WHERE key='$key'";
      $result = $conn->query($sql);
      $data = $result->fetch_assoc()['value'];
      $conn->close();
      return $data;
   }
}

$shardingStorage = new ShardingStorage();
$shardingStorage->saveData('20211201', '100.00');
$data = $shardingStorage->getData('20211201');
echo $data; // 输出：100.00
?>