Spring Filter过滤器,Spring拦截未登录用户权限限制

实现的功能：判断用户是否已登录，未登录用户禁止访问任何页面或action，自动跳转到登录页面。
比较好的做法是不管什么人都不能直接访问jsp页面，要访问就通过action，这样就变成了一个实实在在的权限控制了。
那么就有3种方法可以解决楼主的问题
1，直接使用filter
2，直接使用webwork的interceptor，
3，将action交给spring管理，使用spring的Aop机制

让用户可以直接访问jsp本来就违反了mvc的本意了
1 直接使用filter
web.xml配置

 <filter>  
	    <filter-name>SecurityServlet</filter-name>  
	    <filter-class>com.*.web.servlet.SecurityServlet</filter-class>  
	</filter>  
	<filter-mapping>  
	    <filter-name>SecurityServlet</filter-name>  
	    <url-pattern>*.jsp</url-pattern>  
	</filter-mapping>  
	<filter-mapping>  
	    <filter-name>SecurityServlet</filter-name>  
	    <url-pattern>*.do</url-pattern>  
	</filter-mapping> 

SecurityServlet 类

package com.*.web.servlet;

import java.io.IOException;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
public class SecurityServlet extends HttpServlet implements Filter {
	private static final long serialVersionUID = 1L;

	public void doFilter(ServletRequest arg0, ServletResponse arg1, FilterChain arg2) throws IOException, ServletException {
	  	   HttpServletRequest request=(HttpServletRequest)arg0;   
		   HttpServletResponse response  =(HttpServletResponse) arg1;    
		   HttpSession session = request.getSession(true);     
		   String usercode = (String) request.getRemoteUser();// 登录人
		   String user_role = (String)session.getAttribute("role");//登录人角色
		   String url=request.getRequestURI();   
		   if(usercode==null || "".equals(usercode) || user_role == null || "".equals(user_role)) {      
	            //判断获取的路径不为空且不是访问登录页面或执行登录操作时跳转   
	            if(url!=null && !url.equals("") && ( url.indexOf("Login")<0 && url.indexOf("login")<0 )) {   
	                response.sendRedirect(request.getContextPath() + "/login.jsp");   
	                return ;   
	            }              
	        }   
            arg2.doFilter(arg0, arg1);   
            return;   
	}
	public void init(FilterConfig arg0) throws ServletException {
	}

}

配置中的filter-mapping，定义的是需过滤的请求类型，上面的配置即过滤所有对jsp页面和action的请求。过滤器的实现与struts2、spring框架无关，在用户请求被相应前执行，在过滤器中，可使用response.sendRedirect("")等方法

跳转到需要的链接，如登录页面、错误页面等，不需要跳转时，arg2.doFilter(arg0, arg1);即可继续执行用户的请求。注意使用filter时避免连续两次跳转，否则会报java.lang.IllegalStateException错误，具体配置方法网上有，除非必要，不建议使用/*(过滤所有访问)的配置方式，这样配置，图片、js文件、css文件等访问都会被过滤


2 Spring拦截

Spring配置

<bean id="springSessionInterceptor" class="com.*.web.servlet.SpringLoginInterceptor" >
	 </bean>
<bean id="autoPorxyFactoryBean1"
		class="org.springframework.aop.framework.autoproxy.BeanNameAutoProxyCreator">
		<property name="interceptorNames">
			<list>
				<value>springLoginInterceptor</value>
			</list>
		</property>
		<property name="beanNames" >
		<list>
			<value>*Controller</value>
			</list>
		</property>
	</bean>

SpringLoginInterceptor实现类

package com.web.servlet;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.aopalliance.intercept.MethodInterceptor;
import org.aopalliance.intercept.MethodInvocation;
import org.apache.log4j.Logger;
import org.apache.struts.action.ActionMapping;

public class SpringLoginInterceptor implements MethodInterceptor {
	private static final Logger log = Logger
	.getLogger(SpringLoginInterceptor .class);

	@Override
	public Object invoke(MethodInvocation invocation) throws Throwable {
		log.info("拦截开始！");
		Object[] args = invocation.getArguments();  
		HttpServletRequest request = null;
		HttpServletResponse response = null;
		ActionMapping  mapping = null;
		for (int i = 0 ; i < args.length ; i++ )    {
		  if (args[i] instanceof HttpServletRequest) request = (HttpServletRequest)args[i];   
		  if (args[i] instanceof HttpServletResponse) response = (HttpServletResponse)args[i];   
		  if (args[i] instanceof ActionMapping) mapping = (ActionMapping)args[i];   
		}
		if (request != null && mapping != null) {
			String url=request.getRequestURI();   
		    HttpSession session = request.getSession(true);     
		    String usercode = (String) request.getRemoteUser();// 登录人
		    String user_role = (String)session.getAttribute("user_role");//登录人角色
		    
		    if (usercode == null || usercode.equals("")) {
				if ( url.indexOf("Login")<0 && url.indexOf("login")<0 ) {
					
					return mapping.findForward("loginInterceptor");
				}  
				return invocation.proceed(); 
			}
		    else {
		    	return invocation.proceed();
		    }
		}
		else {
			return invocation.proceed();
		}
	}
}