php匹配html中的日期进行修改并且重新写入html

    $id = getgpc('aim_id') ?: "";
                $dir = getgpc('dir') ?: "";
                $new_date = getgpc('new_date') ?: "";

                if (!$id || !$dir) {
                    $display = 0;
                    $getMsgByTid = "url不合法";
                }
                /*操作*/
                /*1 wap*/
                $array = array('news_id' => $id, 'date_new' => $new_date);
                $_ENV['wap_change_record']->add_one($array);
                $getMsgByTid = "WAP更新成功！";
                /*2 PC 修改文件*/
                chmod($dir, 777);
                $file_content = file_get_contents($dir);


                if ($file_content) {
                    $date_str = "<SPAN>".date("Y年m月d日",strtotime($new_date))."</SPAN>";
                    //$patten = "/^\d{4}[\-](0?[1-9]|1[012])[\-](0?[1-9]|[12][0-9]|3[01])(\s+(0?[0-9]|1[0-9]|2[0-3])\:(0?[0-9]|[1-5][0-9])\:(0?[0-9]|[1-5][0-9]))?$/";
                    $patten = "/<SPAN>\d{4}年(0?[1-9]|1[012])月(0?[1-9]|[12][0-9]|3[01])日<\/SPAN>/";

                    $match = preg_match($patten,$file_content);

                    $update_str = preg_replace($patten, $date_str, $file_content);
                    $re1 = file_put_contents($dir, $update_str);
                  //  $getMsgByTid .= "换取文字：" . $update_str;

                    if ($re1) {
                        $getMsgByTid .= "PC更新成功！";
                    } else {
                        $getMsgByTid .= "PC更新失败！";
                    }

                } else {
                    $getMsgByTid .= "PC未读取到文件：" . $dir;
                }