//多维数组返回一维数组，拼接字符串输出
public function r_implode( $glue, $pieces )
{
foreach( $pieces as $r_pieces )
{
if( is_array( $r_pieces ) ) {
$retVal[] = self::r_implode( $glue, $r_pieces );
} else {
$retVal[] = $r_pieces;
}
}
return implode( $glue, $retVal );
}