jsp中EL表达式在判断时如何取值呢

Question

${users.getUsers_name()!=""?"欢迎你"+${usershttp://ask.csdn.net/questions/238187#.getUsers_name()}:"您还没有登陆,请登录"}
如果登陆成功，我想把用户名也得到，但是不行呢

Answer 1

${ !empty(users.getUsers_name())?"欢迎你${users.getUsers_name()}":"您还没有登陆,请登录"}

或者

 <c:choose>
    <c:when test="${empty var1}">
        var1 is empty or null.
    </c:when>
    <c:otherwise>
        var1 is NOT empty or null.
    </c:otherwise>
</c:choose>