rendered屬性是用來控制該控件是否顯示的,結果為ture時顯示,false隐藏
例:
頁面
<h:commandButton id="login" value="Login" action="#{login.login}" rendered="#{!login.loggedIn}"/>
<h:commandButton id="logout" value="Logout" action="#{login.logout}" rendered="#{login.loggedIn}"/>
java
public boolean isLoggedIn() {
return currentUser != null;
}