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    ReflectionClass::getAttributes

    (PHP 8)

    ReflectionClass::getAttributes — 获取所有属性

    说明

    public ReflectionClass::getAttributes(?string $name = null, int $flags = 0): array

    返回类中声明的所有属性，类型是由 ReflectionAttribute 组成的 array。

    参数

    name

    过滤结果，匹配此类名，仅包含 ReflectionAttribute 实例的属性。

    flags

    如果提供了 name，则用于确定如何过滤结果的 flag。

    默认值为 0，这将导致返回的结果只属于类 name 的属性。

    唯一可用的其他选项是使用 ReflectionAttribute::IS_INSTANCEOF，它将改为使用 instanceof 进行过滤。

    返回值

    由 ReflectionAttribute 对象组成的属性数组。

    示例

    示例 #1 基础用法

    <?php
    #[Attribute]
    class     Fruit {
    }

    #[    Attribute]
    class     Red {
    }

    #[    Fruit]
    #[    Red]
    class     Apple {
    }

    $class = new ReflectionClass('Apple');
    $attributes = $class->getAttributes();
    print_r(array_map(fn($attribute) => $attribute->getName(), $attributes));
    ?>

    以上示例会输出：

    Array
(
    [0] => Fruit
    [1] => Red
)

    示例 #2 通过类名过滤结果

    <?php
    #[Attribute]
    class     Fruit {
    }

    #[    Attribute]
    class     Red {
    }

    #[    Fruit]
    #[    Red]
    class     Apple {
    }

    $class = new ReflectionClass('Apple');
    $attributes = $class->getAttributes('Fruit');
    print_r(array_map(fn($attribute) => $attribute->getName(), $attributes));
    ?>

    以上示例会输出：

    Array
(
    [0] => Fruit
)

    示例 #3 通过类名和继承过滤结果

    <?php
    interface Color {
    }

    #[    Attribute]
    class     Fruit {
    }

    #[    Attribute]
    class     Red implements Color {
    }

    #[    Fruit]
    #[    Red]
    class     Apple {
    }

    $class = new ReflectionClass('Apple');
    $attributes = $class->getAttributes(Color::class, ReflectionAttribute::IS_INSTANCEOF);
    print_r(array_map(fn($attribute) => $attribute->getName(), $attributes));
    ?>

    以上示例会输出：

    Array
(
    [0] => Red
)

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    User Contributed Notes 2 notes

    up
    2
    sandrenyl at gmail dot com
    3 years ago
    When using the method getAttributes() to fetch attributes based on a parent class, the proper flag constant is ReflectionAttribute::IS_INSTANCEOF (which equals 2 as mentionned by sergiolibe).

    <?php
    $reflectionClass    ->getAttributes(SomeParentAttribute::class, ReflectionAttribute::IS_INSTANCEOF);
    ?>
    up
    1
    sergiolibe at gmail dot com
    3 years ago
    When using getAttributes() with specific attribute class and flags, flag 0 will return just matching attributes with specified class, and 2 will return matching attributes with specified class and children of that class:
    <?php
            #[Attribute(\Attribute::TARGET_CLASS)]
            class SomeAttribute {}

            #[Attribute(\Attribute::TARGET_CLASS)]
            class ChildAttribute extends SomeAttribute {}

            #[SomeAttribute]
        #[SomeChildAttribute]
            class SomeClass {}

            $rc = new ReflectionClass(SomeClass::class);

            $r_atts = $rc->getAttributes(SomeAttribute::class, 0); // 0 is default, just given class
            echo json_encode(array_map(fn(ReflectionAttribute $r_att) => $r_att->getName(), $r_atts)), PHP_EOL;

            $r_atts = $rc->getAttributes(SomeAttribute::class, 2); // given class and children classes
            echo json_encode(array_map(fn(ReflectionAttribute $r_att) => $r_att->getName(), $r_atts)), PHP_EOL;
    ?>

    output:
    ["SomeAttribute"]
    ["SomeAttribute","ChildAttribute"]
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