springframework 'form' tag + spring security auth -

what want. want spring security auth springframework tag 'form'. example

<!-- jsp --> <form:form action="login" commandname="?" >  <form:errors path="lasterror" ></form:errors>  <form:input path="j_username" />  <form:password path="j_password" />  <form:button value="submit" name="submit" /> </form:form>  <!-- security-context.xml --> <http use-expressions="true">   <intercept-url pattern="/client/**" access="hasrole('role_user')" />   <form-login login-page="/login" login-processing-url="/login"     authentication-failure-handler-ref="authhandler" />   <logout logout-url="/logout" logout-success-url="/" /> </http> 

what should instead of "?" in form commandname or how can wily action? thanx suggestions.

put loginbean in commandname contains j_username , j_password.

how make validation in spring security login form?