PHP解决JSON中文显示问题

<?php 
function Notice(){
    include './include/conn.php';  //数据库链接文件
    $sql_notice = mysql_query('SELECT * FROM gg_notice where enable = "1" limit 0,10');
    $notice = mysql_fetch_array($sql_notice, MYSQL_ASSOC);
    $str = json_encode($notice);
    //linux
    return preg_replace("#\u([0-9a-f]{4})#ie", "iconv('UCS-2BE', 'UTF-8', pack('H4', '\1'))", $str);
    //windows
    //return preg_replace("#\u([0-9a-f]{4})#ie", "iconv('UCS-2LE', 'UTF-8', pack('H4', '\1'))", $str);
    
}
?>

<?php
/**
 * json 生成,分析 支持中文
 */
class Json_Helper {
    /**
     * 生成json
     */
    public static function encode($str){
        $json = json_encode($str);
        //linux
        return preg_replace("#\u([0-9a-f]{4})#ie", "iconv('UCS-2BE', 'UTF-8', pack('H4', '\1'))", $json);
        //windows
        //return preg_replace("#\u([0-9a-f]{4})#ie", "iconv('UCS-2LE', 'UTF-8', pack('H4', '\1'))", $json);
    }
    /**
     * 分析json
     */
    public static function decode($str) {
        return json_decode($str);
    }
}
?>

$str= preg_replace("#\u([0-9a-f]+)#ie", "iconv('UCS-2', 'UTF-8', pack('H4', '\1'))", $str);

$code = urldecode(json_encode(urlencode("厦门")));

echo json_encode("厦门", JSON_UNESCAPED_UNICODE);

/*
    字符串GBK转码为UTF-8，数字转换为数字。
*/
function ct2($s){
    if(is_numeric($s)) {
        return intval($s);
    } else {
        return iconv("GBK","UTF-8",$s);
    }
}
/*
    批量处理gbk->utf-8
*/
function icon_to_utf8($s) {
  if(is_array($s)) {
    foreach($s as $key => $val) {
      $s[$key] = icon_to_utf8($val);
    }
  } else {
      $s = ct2($s);
  }
  return $s;
}
echo json_encode(icon_to_utf8("厦门"));