我已经安装了Tomcat 7.0.53，但在运行时，它说我没有被授权。然后我更改了Tomcat-users.xml并输入了角色和正确的密码，但是当我打开localhost并尝试登录时，它仍显示＆＃34;未授权＆＃34;。请帮我解决这个问题。
Tomcat的users.xml中：
<role rolename="manager,admin,standard"/>
<user username="tomcat" password="password" roles="manager,admin,standard"/>
记录时：
401 Unauthorized
You are not authorized to view this page. If you have not changed any configuration files, please examine the file conf/tomcat-users.xml in your installation. That file must contain the credentials to let you use this webapp.