json_decode - 对 JSON 格式的字符串进行编码
mixed json_decode( string $json)
This function only works with UTF-8 encoded data.
<?php
$json = '{"foo-bar": 12345}';
$obj = json_decode($json);
print $obj->{'foo-bar'}; // 12345
?>
原文
http://www.php.net/manual/zh/function.json-decode.php