在PHP中訪問對象屬性和方法需使用->操作符，若屬性或方法為私有則需通過公共方法獲取，具體如下：1.創(chuàng)建對象后用$object->property或$object->method()訪問公有屬性和方法；2.私有或受保護(hù)成員需通過getter/setter等公共方法間接訪問；3.靜態(tài)屬性和方法通過類名::直接訪問。掌握這些規(guī)則可有效避免誤用操作符并實(shí)現(xiàn)對數(shù)據(jù)的封裝與控制。

In PHP, accessing object properties and methods is straightforward once you understand the basics of object-oriented programming (OOP). When you create an object from a class, you can interact with it using the arrow operator (->). Here’s how to do it properly.

Accessing Object Properties

After creating an instance of a class, you access its properties using the -> symbol followed by the property name. This only works if the property is accessible — meaning it's not declared as private or protected.

Example:

class Car {
    public $color = 'red';
}

$myCar = new Car();
echo $myCar->color; // Outputs: red

A few things to keep in mind:

• Always check if the property exists before trying to access it.
• Use public visibility for properties you want to access outside the class.
• You can also dynamically assign values:

  $myCar->color = 'blue';

If the property is private or protected, you'll need to use getter methods (more on that below).

Calling Object Methods

Just like with properties, you use the -> operator to call methods on an object. The method must be defined in the class and accessible (not private if you're calling it from outside the class).

Example:

class Car {
    public function startEngine() {
        echo 'Engine started';
    }
}

$myCar = new Car();
$myCar->startEngine(); // Outputs: Engine started

Tips when working with methods:

• Make sure the method is defined in the class.
• If the method requires parameters, pass them inside the parentheses.
• You can chain method calls if they return the object itself:

  $myCar->setColor('green')->startEngine();

This kind of chaining is common in fluent interfaces or builder patterns.

Handling Private and Protected Members

You can't directly access private or protected properties or methods from outside the object. That’s where getters and setters come in handy.

Example:

class Car {
    private $color;

    public function setColor($color) {
        $this->color = $color;
    }

    public function getColor() {
        return $this->color;
    }
}

$myCar = new Car();
$myCar->setColor('black');
echo $myCar->getColor(); // Outputs: black

Why this matters:

• It gives you control over how data is set and retrieved.
• You can validate input inside setter methods.
• It follows OOP principles like encapsulation.

So even though you can’t access $myCar->color directly here, you can safely manipulate it through public methods.

Working with Static Properties and Methods

Sometimes you don’t need an object instance to access a property or method. In those cases, use static.

Example:

class Car {
    public static $wheels = 4;

    public static function showWheels() {
        echo self::$wheels;
    }
}

echo Car::$wheels;       // Outputs: 4
Car::showWheels();        // Outputs: 4

Key points:

• Use the scope resolution operator :: instead of ->.
• Inside the class, refer to static members with self::.
• Static methods can't access non-static properties unless you instantiate the class inside the method.

Keep in mind that static members are shared across all instances of the class.

基本上就這些。只要理解對象和類的關(guān)系，再掌握訪問修飾符的作用，操作屬性和方法就不會太難。不過有一點(diǎn)容易忽略的是，有時候你可能會誤用 -> 和 ::，特別是在處理靜態(tài)成員的時候，這個要特別注意。

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