匿名類在PHP 7中用於快速創(chuàng)建一次性對(duì)象，無需定義完整類。它們適用於僅需單個(gè)實(shí)例的場(chǎng)景，如單元測(cè)試中的測(cè)試樁或臨時(shí)接口實(shí)現(xiàn)，從而避免不必要的類定義。其語法為使用new class關(guān)鍵字，並可傳遞構(gòu)造參數(shù)、聲明屬性和方法，且支持訪問修飾符。例如：$obj = new class(100, 200) { ... };。然而，匿名類無名稱，無法跨文件復(fù)用，調(diào)試時(shí)顯示為class@anonymous，且每次定義的匿名類即使結(jié)構(gòu)相同也被視為不同類。因此，它們適合輕量級(jí)、臨時(shí)用途，但不適合複雜邏輯或廣泛復(fù)用。

Anonymous classes in PHP 7 are a way to create simple, one-off objects without formally defining a class. They're useful when you need an object quickly and don't want the overhead of creating a full named class.

When Would You Use an Anonymous Class?

You'll often reach for an anonymous class when you only need a single instance of an object — for example, setting up test doubles in unit tests or implementing small interfaces on the fly. It helps keep your code clean by avoiding unnecessary class definitions that may only be used once.

Let's say you're working with an interface like Logger , and you just need a quick implementation for a specific situation. Instead of making a whole new class file, you can define it inline:

 $logger = new class {
    public function log($message) {
        echo $message;
    }
};

This is especially handy during testing or prototyping, where you want flexibility without extra boilerplate.

How Do You Define an Anonymous Class?

The syntax is straightforward: use the new class keywords. You can pass constructor arguments just like with regular classes, and implement interfaces or extend other classes if needed.

Here's a basic example:

 $obj = new class(100, 200) {
    public function __construct(
        private int $x,
        private int $y
    ) {}

    public function sum(): int {
        return $this->x $this->y;
    }
};

echo $obj->sum(); // Outputs: 300

• Constructor parameters are passed directly after new class(...)
• You can declare properties and methods inside the class body
• Visibility modifiers (public, private, protected) work as usual

They behave like normal objects — you can call methods, access properties (if public), and even type-check them.

What Are the Limitations?

Anonymous classes come with a few caveats:

• No name : So you can't reference them elsewhere or autoload them.
• Limited reusability : Since they're defined inline, they aren't ideal for complex logic or reuse across files.
• Debugging : Stack traces will show something like class@anonymous , which can make debugging trickier.

Also, each time you define an anonymous class, even if it looks identical, PHP treats it as a different class. That means two anonymous classes with the same structure aren't considered equal.

That's the core idea behind anonymous classes in PHP 7 — they're a lightweight tool for quick object creation. Useful in the right context, but not meant for every situation.

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