PHP封装mysqli基于面向对象的mysql数据库操作类与用法示例

<?phpclass Mysql{     private static $host="localhost";     private static $user="root";     private static $password="123456";     private static $dbName="test";           //数据库名     private static $charset="utf8";          //字符编码     private static $port="3306";            //端口号     private $conn=null;     function __construct(){       $this->conn=new mysqli(self::$host,self::$user,self::$password,self::$dbName,self::$port);       if(!$this->conn)       {          die("数据库连接失败！".$this->conn->connect_error);       }else{         echo "连接成功！";       }       $this->conn->query("set names ".self::$charset);     }     //执行sql语句     function sql($sql){       $res=$this->conn->query($sql);     if(!$res)       {          echo "数据操作失败";       }       else       {          if($this->conn->affected_rows>0)          {             return $res;          }          else          {            echo "0行数据受影响！";          }       }     }     //返回受影响数据行数     function getResultNum($sql){      $res=$this->conn->query($sql);      return mysqli_num_rows($res);      }     //关闭数据库     public function close()     {       @mysqli_close($this->conn);     }}?>

<?phprequire_once "mysql.php";$conn=new Mysql();$sql="select * from user";//执行查询并获取查询结果$result=$conn->sql($sql);//输出受影响数据行数$num=$conn->getResultNum($sql);echo "影响的行数：".$num;//读取并输出记录while ($row = mysqli_fetch_assoc($result)){  echo "{$row['name']} ";  echo "{$row['password']}";}//关闭数据库$conn->close();