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php学习笔记之面向对象编程

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Jun 08, 2016 pm 05:24 PM

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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。

代码如下

复制代码

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 ( $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 "

"; <br>
print_r ( $chanelInfo );
<p>class a { <br>
    protected  function aa(){ <br>
        echo 222; <br>
    } <br>
} <br>
class b extends a{ <br>
    function bb(){ <br>
        $this->aa(); <br>
    } <br>
} <br>
$c = new b(); <br>
$c->bb();</p>

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

陳述

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