如何在PHP中该类的另一个函数内调用同一类的函数

Question

当我在showAll内调用函数connect和closeDb时，出现错误。

class DBConnect {

private $con;

private function connect() {

    $con = mysql_connect("localhost", "root", "");
    mysql_select_db('school');
}

private function closeDb() {
    mysql_close($this->con);
}

public function showAll() {
    self::connect();

    echo "THis is from the showAll method";
    self::closeDb();
}

}

Answer 1

Mysql扩展在PHP 5.5.0中已弃用，在PHP 7.0.0中已删除。 相反，应使用MySQLi或PDO_MySQL扩展。

了解面向对象编程的基础知识： http : //php.net/manual/zh/language.oop5.php

Answer 2

这条线看起来是错误的。 $con = mysql_connect("localhost", "root", "");

如果想做$this->con = mysql_connect("localhost", "root", "");

然后

public function showAll() { $this->connect(); echo "THis is from the showAll method"; $this->closeDb(); } public function showAll() { $this->connect(); echo "THis is from the showAll method"; $this->closeDb(); } 使用$ this！