适配器模式

    • 适配器模式(Adapter）模式：将一个类的接口，转换成客户期望的另一个类的接口。适配器让原本接口不兼容的类可以合作无间。列如：将数据库接口封装成一样的接口， 这样就可以适用于不同场景

    • 案例 将php数据操作封装成统一的api

      • 统一接口api

        <?php
namespace Test;

interface IDatabase
  {
        function connect($host, $user, $passwd, $dbname);
        function query($sql);
        function close();
  }

        • mysql 连接

          
<?php
namespace Test;
class MySQL implements IDatabase
{
        protected $conn;
        function connect($host, $user, $passwd, $dbname)
        {
                $conn = mysql_connect($host, $user, $passwd);
                mysql_select_db($dbname, $conn);
              $this->conn = $conn;
        }

      function query($sql)
      {
          $res = mysql_query($sql, $this->conn);
          return $res;
      }

    function close()
    {
            mysql_close($this->conn);
    }
}
      • mysqli 连接
    <?php
namespace TEST;
class MySQLi implements IDatabase
{
    protected $conn;

    function connect($host, $user, $passwd, $dbname)
    {
        $conn = mysqli_connect($host, $user, $passwd, $dbname);
        $this->conn = $conn;
    }

    function query($sql)
    {
        return mysqli_query($this->conn, $sql);
    }

    function close()
    {
        mysqli_close($this->conn);
    }
}
    • PDO连接
    <?php
namespace Test;
class PDO implements IDatabase
{
    protected $conn;
    function connect($host, $user, $passwd, $dbname)
    {
        $conn = new \PDO("mysql:host=$host;dbname=$dbname", $user, $passwd);
        $this->conn = $conn;
    }

    function query($sql)
    {
        return $this->conn->query($sql);
    }

    function close()
    {
        unset($this->conn);
    }
}
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