php学习笔记之面向对象编程
一个php初学者的一个学习笔记的面向对象编程实例,有需要学习的朋友可参考参考.
PHP实例代码如下:
class db { private $mysqli ; //数据库连接 private $options ; //SQL选项 private $tableName ; //表名 public function __construct( $tabName ) { $this ->tableName = $tabName ; $this ->db (); } private function db() { $this ->mysqli = new mysqli ( 'localhost' , 'root' , '' , 'hdcms' ); $this ->mysqli->query( "SET NAMES GBK" ); } public function fields( $fildsArr ) { if ( empty empty ( $fildsArr )) { $this ->options [ 'fields' ] = '' ; } if ( is_array ( $fildsArr )) { $this ->options [ 'fields' ] = implode ( ',' , $fildsArr ); } else { $this ->options [ 'fields' ] = $fildsArr ; } return $this ; } public function order( $str ) { $this ->options [ 'order' ] = "ORDER BY " . $str ; return $this ; } public function select() { $sql = "SELECT {$this->options['fields']} FROM {$this->tableName} {$this->options['order']}" ; return $this ->query ( $sql ); } private function query( $sql ) { $result = $this ->mysqli ->query ( $sql ); $rows = array (); while ( $row = $result ->fetch_assoc () ) { $rows [] = $row ; } return $rows ; } private function close() { $this ->mysqli ->close (); } function __destruct() { $this ->close (); } } $chanel = new db ( "hdw_channel" ); $chanelInfo = $chanel ->fields ( 'id,cname,cpath' ) ->select (); echo "<pre>" ; print_r ( $chanelInfo ); class a { protected function aa(){ echo 222; } } class b extends a{ function bb(){ $this ->aa(); } } $c = new b(); $c ->bb();public 公有的:本类,子类,外部对象都可以调用.
protected 受保护的:本类 子类,可以执行,外部对象不可以调用.
private 私有的:只能本类执行,子类与外部对象都不可调用.
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