PHP魔法方法是自動觸發(fā)的特殊函數(shù)，用於響應(yīng)對象相關(guān)事件。它們以雙下劃線開頭，無需手動調(diào)用。 1.__construct()用於對像初始化，創(chuàng)建實例時自動執(zhí)行；2.__destruct()在對象銷毀時進行清理操作；3.__get()和__set()處理未定義屬性的讀寫；4.__call()和__callStatic()處理未定義的方法調(diào)用；5.__toString()定義對象轉(zhuǎn)字符串時的表現(xiàn)形式。這些方法提升了對象行為的靈活性和可定制性。

PHP magic methods are special functions that get triggered automatically in response to specific events or actions involving an object. They're called "magic" because they don't need to be called directly — they run behind the scenes when certain conditions are met. These methods always start with double underscores ( __ ), and they allow developers to customize how objects behave in various situations.

Here are a few commonly used magic methods in PHP:

__construct() – Object Initialization

This is probably the most widely used magic method. It's automatically called when a new instance of a class is created. You use it to set up initial values or perform setup tasks.

Example:

 class User {
    public function __construct($name) {
        echo "User {$name} created.";
    }
}

When you do new User("Alice") , the message will show up. It's not just for printing — it's often used to inject dependencies or initialize properties.

__destruct() – Cleanup After Object Is No Longer Needed

This method runs when an object is destroyed or when the script ends. It's useful for cleaning up resources like file handles, database connections, or memory.

Example:

 public function __destruct() {
    // Close a database connection or log something
}

Note: You can't pass parameters to __destruct() and it's not guaranteed to run if the script crashes or is terminated abruptly.

__get() and __set() – Handling Undefined Properties

These two methods help manage access to inaccessible or undefined properties.

• __get($property) is called when you try to read a property that's not accessible or doesn't exist.
• __set($property, $value) is triggered when writing to such a property.

They're useful for lazy loading or creating dynamic properties without explicitly defining them.

Example:

 class Product {
    private $data = [];

    public function __set($name, $value) {
        $this->data[$name] = $value;
    }

    public function __get($name) {
        return $this->data[$name] ?? null;
    }
}

Now you can do things like:

 $product = new Product();
$product->price = 100;
echo $product->price; // Outputs: 100

__call() and __callStatic() – Handling Undefined Methods

If you try to call a method that doesn't exist or isn't visible:

• __call($method, $args) handles instance method calls.
• __callStatic($method, $args) handles static method calls.

These are handy for implementing fallback logic or dynamic method handling.

Example:

 public function __call($method, $args) {
    if (strpos($method, 'get') === 0) {
        $property = lcfirst(substr($method, 3));
        return $this->$property ?? null;
    }
}

With this, calling $obj->getName() would return the value of $this->name if it exists, even if there's no explicit getName() method.

__toString() – Custom Object String Representation

This method allows an object to be treated like a string, for example when using echo $object .

You must return a string value from this method. If you return something else, PHP will throw an error.

Example:

 public function __toString() {
    return "This is a " . __CLASS__;
}

Now echo $obj; will output: This is a MyClass .

There are other magic methods too — like __invoke() , __sleep() , __wakeup() , __clone() , and more — but the ones above are the most commonly encountered in day-to-day development.

基本上就這些。

以上是什麼是PHP魔術(shù)方法，並列出一些常見方法。的詳細內(nèi)容。更多資訊請關(guān)注PHP中文網(wǎng)其他相關(guān)文章！