Question

php关于json_encode输出的问题

<?php
class User {
public $pub = "Mister X.";
protected $pro = "hidden";
private $priv = "hidden too";

public $func;
public $notUsed;

public function __construct() {
$this->func = function() {
return "Foo";
};
}
}

$user = new User();

// Returns: {"pub":"Mister X.","func":{},"notUsed":null}
echo json_encode($user);
?>
输出：
{"pub":"Mister X.","func":{},"notUsed":null}
问题:
为什么func的输出值是{}, 而notUsed的输出值是null?

Answer 1

$this->func = function() {
return "Foo";
};
这句话 $this->func 就是 $func