你能帮助我更好地理解PHP类吗？

假设你有一辆车……一辆车可以容纳人,里面有人.

class Car {
    private $people = array();
    private $capacity;

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

    function addPerson($name) {
        if(count($this->people) >= $this->capacity) {
            throw new Exception("Car is already at capacity");
        } else {
            $this->people[] = $name;
        }
    }
    function getPeople() { return $this->people; }
    function getCapacity() { return $this->capacity; }
}

现在,我们可以开始使用这些车：

$aliceCar = new Car(2);
$aliceCar->addPerson("Alice");

$bobCar = new Car(4);
$bobCar->addPerson("Bob");
$bobCar->addPerson("Jake");

我现在有2辆汽车(实例),它们拥有不同的数据.

echo implode(',',$aliceCar->getPeople()); // Alice
echo $aliceCar->getCapacity(); // 2

echo implode(',$bobCar->getPeople()); // Bob,Jake
echo $bobCar->getCapacity(); // 4

我可能还想要一辆面包车,它将为门提供额外的属性：

class Van extends Car {
    private $num_doors;

    function __construct($capacity,$num_doors) {
        parent::__construct($capacity); // Call the parent constructor
        $this->num_doors = $num_doors;
    }

    function getNumDoors() { return $this->num_doors; }
}

现在让我们使用那辆面包车：

$jakeVan = new Van(7,5);

// Van is ALSO a Car
$jakeVan->addPerson("Ron"); //Jake is with Bob now,so his son is driving the Van
$jakeVan->addPerson("Valery") //Ron's girlfriend

echo implode(',$jakeVan->getPeople()); // Ron,Valery
echo $jakeVan->getCapacity(); // 7
echo $jakeVan->getNumDoors(); // 5

现在也许您可以看到我们如何将这些概念应用于创建DBTable和User类.

实际上,很难真正开始解释为什么类在不涉及面向对象编程(抽象,封装,继承,多态)的概念的情况下简化了一个人的生活.

我建议你阅读以下书籍.它将帮助您掌握OOP的核心概念,并帮助您理解为什么对象真正让您的生活更轻松.如果不理解这些概念,很容易将类视为另一个复杂问题.

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