求解一个filter问题
这个filter的意思是登录后才能浏览其他页面
xml配置如下
<filter>
   <filter-name>SecurityFilter</filter-name>
   <filter-class>com.csy.filter.SecurityFilter</filter-class>
  </filter>
  <filter-mapping>
   <filter-name>SecurityFilter</filter-name>
   <url-pattern>/index.jsp</url-pattern>
   <dispatcher>REQUEST</dispatcher>
   <dispatcher>FORWARD</dispatcher>
  </filter-mapping>

filtet代码如下
package com.csy.filter;

import java.io.IOException;

import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.Filter;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class SecurityFilter implements Filter {

public void init(FilterConfig filterConfig) {

}

public void doFilter(ServletRequest request, ServletResponse response,
FilterChain filterChain) throws ServletException, IOException{
HttpSession session = ((HttpServletRequest)request).getSession();
if(session.getAttribute("login") == null) {
((HttpServletResponse)response).sendRedirect("login.jsp");
} else {
filterChain.doFilter(request, response);
}
}

public void destroy() {

}

}
为什么我还是可以不登录，直接访问到index.jsp呢？
------解决方案--------------------
打个断点调试，如果进不了SecurityFilter 里面的断点，则是web.xml中的拦截器没有写对。参考：

	<filter>

		<filter-name>LoginFilter</filter-name>

		<filter-class>

			com.csy.filter.SecurityFilter

		</filter-class>

	</filter>

	<filter-mapping>

		<filter-name>LoginFilter</filter-name>

		<url-pattern>*.action</url-pattern>

	</filter-mapping>

	<filter-mapping>

		<filter-name>LoginFilter</filter-name>

		<url-pattern>*.jsp</url-pattern>

	</filter-mapping>