如何解决php中文转码的问题

<?php
echo json_encode("中文", JSON_UNESCAPED_UNICODE);
//"中文"

$array = array(
'test'=>urlencode("我是测试")
);
$array = json_encode($array);
echo urldecode($array);
//{"test":"我是测试"}

function decodeUnicode($str)
{
    return preg_replace_callback('/\\\\u([0-9a-f]{4})/i',
        create_function(
            '$matches',
            'return mb_convert_encoding(pack("H*", $matches[1]), "UTF-8", "UCS-2BE");'
        ),
         $str);
}

$arr = array('name1':"中文",'name2':'abc12');
$jsonstr = decodeUnicode(json_encode($arr));