Strut2中Filter过滤器的编写和注册

在Struts2中编写过滤器需要创建一个类，继承 import javax.servlet.Filter; 下面，创建一个判断用户是否登录的Filter：

public class UserLoginValidateFilter implements Filter {

@Override
public void destroy() {
}

@Override
public void doFilter(ServletRequest req, ServletResponse res,
		FilterChain filterChain) throws IOException, ServletException {
	HttpServletRequest request = (HttpServletRequest)req;
	User user = WebUtil.getUser(request);
	if(user == null){
		HttpServletResponse response = (HttpServletResponse)res;
		response.sendRedirect(request.getContextPath() + "/user/Login.action");
	}else{
		filterChain.doFilter(req, res);
	}
}

@Override
public void init(FilterConfig arg0) throws ServletException {
}

}

接下来在web.xml文件中注册，设置需要过滤的URL：

UserLoginValidateFilter com.itzhai.action.filter.UserLoginValidateFilter UserLoginValidateFilter /customer/*