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();
}
}
}
//================================================================
在 SPRING 3 MVC 模式下，还可以如下实现：
public class SecurityFilter extends HandlerInterceptorAdapter {
@Override
public boolean preHandle(HttpServletRequest request,
HttpServletResponse response, Object handler) throws Exception {
System.out.println("==>>Begin to Filter session====");
HttpSession session = request.getSession();
String user = (String) session.getAttribute("user");
System.out.println("===??Current User=="+user);
String curPath=request.getRequestURL().toString();
System.out.println("===>> curpath:"+curPath);
if (curPath.indexOf("GPS/User/Index")>=0){
return true;
}
if(null==user || "".equals(user)){
return true;
/**
* handle session and security if you want.
*/
//request.getRequestDispatcher("/index.jsp").forward(request, response);
}
return super.preHandle(request, response, handler);
}
}
在 name-servlet.xml spring 的配置文件中注明：
<bean id="urlMapping" class="org.springframework.web.servlet.mvc.annotation.DefaultAnnotationHandlerMapping" >
<property name="interceptors">
<list>
<bean class="com.ibm.tds.filter.SecurityFilter"/>
</list>
</property>
</bean>
就可以用了。
来源：https://www.cnblogs.com/bkyliufeng/p/6247541.html