004-对象——public protected private PHP封装的实例

<?php

/**
 *public protected private PHP封装的实例
 */
/*class tv
{
    private $shengyin;

    function __construct()
    {
        $this->shengyin = 20;
    }

    public function yaokongqi($anniu, $liang = '')
    {
        switch ($anniu) {
            case "shengyin":
                $this->shengyin($liang);
                break;
            case "guandiansi":
                $this->guandiansi();
                break;
            case 'huantai':
                $this->huantai($liang);
                break;
            case 'jingyin':
                $this->jinyin($liang);
                break;
        }
    }

    public function shengyin($daxiao)
    {
        $this->shengyin = $daxiao>0?$this->shengyin + $daxiao:$this->shengyin - $daxiao;
        echo "现在的声音是：{$this->shengyin}<br/>";
    }

    private function guandiansi()
    {
        echo "关电视";
    }

    private function huantai($pindao)
    {
        echo "现在是第{$pindao}频道";
    }

    private function jinyin($zhuangtai)
    {
        $zhuangtai == 1 ? "电视静音了" : "打开声音";
    }

    public function huodeshengyin()
    {
        return $this->shengyin;
    }
}

$tv1 = new tv();
$tv1->yaokongqi('shengyin', 6);
echo "现在的电视声音是：".$tv1->huodeshengyin();
*/

//最大化的封装，最小化的释放
/*class db
{
    private $mysqli;//数据库链接
    private $options;//SQL选项
    private $tableName;//表名

    function __construct($tabName)
    {
        $this->tableName = $tabName;
        $this->db();
    }

    private function db()
    {
        $this->mysqli = new mysqli('localhost', 'root', '', 'blog');
        $this->mysqli->query('SET NAMES utf8');
    }

    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;

    }

    function order($str)
    {
        $this->options['order'] = "ORDER BY".$str;
        return $this;
    }

    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('blog_article');
$changelInfo=$chanel->fields('art_id,art_title,art_tag')->select();
echo '<pre>';
print_r($changelInfo);*/

//public () 本类，子类 ，外部对象都可以执行
//protected  (受保护的) 本类，子类，可以执行，外部对象不可以执行
//private (私有的)  只能在奔雷执行，子类与外部对象都不可以调用

/*class a{
    protected function aa(){
        echo 222;
    }
}
class b extends a{
    function bb(){
        $this->aa();
    }
}
$c=new b();
$c->bb(); //输出：222；*/


/*class a{
    private function aa(){
        echo 222;
    }
}
class b extends a{
    function bb(){
        $this->aa();
    }
}
$c=new b();
$c->bb(); //报错：*/

　　

转载于:https://www.cnblogs.com/yiweiyihang/p/7940060.html