国产av日韩一区二区三区精品,成人性爱视频在线观看,国产,欧美,日韩,一区,www.成色av久久成人,2222eeee成人天堂

self::get_one_by_sql

先確定下父類別的get_one_bysql 是不是靜態(tài)的

關(guān)於使用 https://stackoverflow.com/que...

你這麼用的顯然很不規(guī)範(fàn), 當(dāng)然先說正題.
要調(diào)父類的非靜態(tài)方法, 首先你得取到類實(shí)例
如果有緩存就直接拿, 沒有就創(chuàng)建一個(gè)

$instance = new self();
$totalCount = $instance->get_one_bysql($sqlstr);

呼叫不了.

非靜態(tài)方法需要有$this物件, 從靜態(tài)方法呼叫提供不了這個(gè)物件.

打開註解玩玩就知道了

<?php
class a{
    public $ab = NULL;
    public function d(){
        var_dump($this->ab);
    }
    public function c($a,$b){
        var_dump($a+$b);
    }
}

class b extends a{
    public static function t(){
        // $this->d();          //Fatal error: Using $this when not in object context in D:\phpStudy\WWW\index.php on line 14
        // $this->c(1,2);          //Fatal error: Using $this when not in object context in D:\phpStudy\WWW\index.php on line 15
        // self::d();             //Strict Standards: Non-static method a::d() should not be called statically in D:\phpStudy\WWW\index.php on line 16
                                //Fatal error: Using $this when not in object context in D:\phpStudy\WWW\index.php on line 5
        // self::c(1,2);        //Strict Standards: Non-static method a::c() should not be called statically in D:\phpStudy\WWW\index.php on line 18 
                                // int(3)
        // parent::d();            //Strict Standards: Non-static method a::d() should not be called statically in D:\phpStudy\WWW\index.php on line 20
                                // Fatal error: Using $this when not in object context in D:\phpStudy\WWW\index.php on line 5
        // parent::c(1,2);        //Strict Standards: Non-static method a::c() should not be called statically in D:\phpStudy\WWW\index.php on line 22
                                //int(3)
    }
}
b::t();

總結(jié)：this用於實(shí)例呼叫。 self，parent用於呼叫靜態(tài)屬性或方法。
最後一個(gè)奇特的現(xiàn)像是雖然靜態(tài)呼叫父類別的非靜態(tài)方法處理數(shù)據(jù)，會(huì)得到一個(gè)報(bào)錯(cuò)，但是還是輸出了int(3)