Web App struts框架里实现Filter

webxml里添加filter配置信息

<filter>

<filtername>Authentication</filtername>

<filterclass>

limaswebfiltersAuthenticationFilter

</filterclass>

<initparam>

<paramname>onError</paramname>

<paramvalue>/pages/indexjsp</paramvalue>

</initparam>

</filter>

<filtermapping>

<filtername>Authentication</filtername>

<urlpattern>/protect/*</urlpattern>

</filtermapping>

<filterclass>定义使用limaswebfiltersAuthenticationFilter类执行过滤Action

<initparam>当验证失败后Forward到/pages/indexjsp

<filtermapping>只有当地址包括/protect/时运行filter类

实现limaswebfiltersAuthenticationFilter

package limaswebfilters;

import javaioIOException;

import javaxservletRequestDispatcher;

import javaxservletServletException;

import javaxservlethttp*;

import javaxservletFilter;import javaxservletFilterChain;

import javaxservletFilterConfig;

import limaswebbeanUserBean;

import javaxservletServletRequest;

import javaxservletServletResponse;import orgapachestrutsGlobals;

import orgapachestrutsaction*;

import nstantsConstants;

/**

* Filter implementation for user authentication必须实现Filter接口

* @author tyrone * @version $Id: AuthenticationFilterjavav

*/public class AuthenticationFilter implements Filter{

/**

* filterConfig will store the reference of FilterConfig

*/ private FilterConfig filterConfig;

private String onErrorUrl;

/**

* store the reference of the FilterConfig

* @param config FilterConfig object

* @throws ServletException

*/ public void init(FilterConfig config) throws ServletException

{//获得验证失败forward地址

filterConfig = config;

onErrorUrl=filterConfiggetInitParameter(onError);

if (onErrorUrl==null || equals(onErrorUrl)){

onErrorUrl=/pages/indexjsp;

}

}

/**

* User Authentication isdone If User is authenticated successful then

* control is transferred to logon URI

* @param ServletRequest Request

* @param ServletRequest Response

* @param FilterChain Filter Chain

* @throws ServletExceptionIOException

*/ public void doFilter(ServletRequest request ServletResponse response FilterChain next)

throws IOException ServletException

{

HttpServletRequest httpRequest = (HttpServletRequest)request;

HttpServletResponse httpResponse=(HttpServletResponse)response;

// Current session

HttpSession httpSession = ();

//Session里是否有用户信息

if ((ConstantsUSER_KEY) == null)

{

ActionErrors errors=new ActionErrors();

errorsadd(ActionErrorsGLOBAL_ERROR

new ActionError(error authentication));

(GlobalsERROR_KEYerrors);

//没有验证失败forward到/pages/indexjsp

(onErrorUrl)forward(httpRequesthttpResponse);

}else//成果过滤Action结束

nextdoFilter(requestresponse);

}

/**

* destroy() method is called by the servlet container

*/ public void destroy()

{

}

}