php – 如何检查对象是否为空？

如何检查 PHP对象是否为空(即没有属性)？根据doc,内置的empty()不适用于对象：

5.0.0 Objects with no properties are no longer considered empty.

ReflectionClass :: GetProperties中

http://www.php.net/manual/en/reflectionclass.getproperties.php

class A {
    public    $p1 = 1;
    protected $p2 = 2;
    private   $p3 = 3;
}

$a = new A();
$a->newProp = '1';
$ref = new ReflectionClass($a);
$props = $ref->getProperties();

// Now you can use $props with empty
echo empty($props);

print_r($props);

/* output:

Array
(
    [0] => ReflectionProperty Object
        (
            [name] => p1
            [class] => A
        )

    [1] => ReflectionProperty Object
        (
            [name] => p2
            [class] => A
        )

    [2] => ReflectionProperty Object
        (
            [name] => p3
            [class] => A
        )

)

*/

请注意,newProp不会在列表中返回.

get_object_vars

http://php.net/manual/en/function.get-object-vars.php

使用get_object_vars将返回newProp,但不会返回受保护和私有成员.

因此,根据您的需要,可能需要反射和get_object_vars的组合.