Freemarker replace the replacement process is a NULL value

　　When freemarker object call built-in functions, such as birthDay function, page $ {userInfo.birthDay} call userInfo object, when I want to birthDay values ​​"-"? When replaced by "/", $ {userInfo.birthDay replace ( "-", "/")} when birthDay has a value can be achieved, when the error will birthDay is null.

　　When a null value replacement process can be as follows:

$ {(UserInfo.birthDay replace (? '-', '/'))!} // error message by pressing!.

　　 

　　Pro-test available!