用php将递归xml转换为Json

<?php
$xmlString = '<root>
    <person>
        <name>John Doe</name>
        <age>30</age>
        <address>
            <street>Main Street</street>
            <city>City</city>
        </address>
    </person>
    <person>
        <name>Jane Smith</name>
        <age>25</age>
        <address>
            <street>Second Street</street>
            <city>City</city>
        </address>
    </person>
</root>';

$xml = simplexml_load_string($xmlString);
$json = json_encode($xml);
$array = json_decode($json, true);

echo $json;
?>

{
    "person": [
        {
            "name": "John Doe",
            "age": "30",
            "address": {
                "street": "Main Street",
                "city": "City"
            }
        },
        {
            "name": "Jane Smith",
            "age": "25",
            "address": {
                "street": "Second Street",
                "city": "City"
            }
        }
    ]
}