解决The markup in the document following the root element must be well-formed.

<security-constraint>
<web-resource-collection>
<web-resource-name>RegisteredUsers</web-resource-name>
<url-pattern>/ch06/6.3/6.3.4/security.jsp</url-pattern>
</web-resource-collection>
<auth-constraint> <!-- 可以访问的角色 -->
<role-name>registered_user</role-name>
<role-name>admin</role-name>
</auth-constraint>
</security-constraint>

<login-config>
<auth-method>BASIC</auth-method>
<realm-name>Registered Users</realm-name>
</login-config>

<security-role>
<role-name>admin</role-name>
</security-role>

<security-role>
<role-name>registered_user</role-name>
</security-role>

<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"> <security-constraint>
<web-resource-collection>
<web-resource-name>RegisteredUsers</web-resource-name>
<url-pattern>/ch06/6.3/6.3.4/security.jsp</url-pattern>
</web-resource-collection>
<auth-constraint> <!-- 可以访问的角色 -->
<role-name>registered_user</role-name>
<role-name>admin</role-name>
</auth-constraint>
</security-constraint>

<login-config>
<auth-method>BASIC</auth-method>
<realm-name>Registered Users</realm-name>
</login-config>

<security-role>
<role-name>admin</role-name>
</security-role>

<security-role>
<role-name>registered_user</role-name>
</security-role>
</web-app>