struts2 注解 使用拦截器判断用户是否登录

配置struts.xml

<!--     定义全局package -->
  <package name="defaultpackage" extends="struts-default">
    <interceptors>
   <interceptor-stack name="defStack">
    <interceptor-ref name="defaultStack"></interceptor-ref>
<!--把自己的拦截器添加到定义的拦截器栈里面-->
    <interceptor-ref name="sessionNull"></interceptor-ref>
   </interceptor-stack>
<!--定义自己的拦截器-->
   <interceptor name="sessionNull" class="com.jyjsf.interceptor.SessionNullInterceptor" />
  </interceptors>
<!--调用拦截器-->
  <default-interceptor-ref name="defStack" />
  
<!--定义全局结果集-->
  <global-results>
                 <result name="sessionnull">
                       /login.jsp
                 </result>    
            </global-results>
  
 </package>

  添加拦截器类

public class SessionNullInterceptor extends AbstractInterceptor {

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;

	@Override
	public String intercept(ActionInvocation invocation) throws Exception {
		User u=(User) ActionContext.getContext().getSession().get("user");
		if(u!=null){
			return invocation.invoke();
		}
		return "sessionnull";
	}

}

 所有Action类继承这个全局package

//@Component("userAciton")
/*
 * 用户的Action类
 * @author DZWei
 */
@ParentPackage(value = "defaultpackage")//应用全局包
@Scope("prototype")
@Namespace("/")
public class UserAction extends BaseAction {
	@Action(value = "initializationAction", results = {
			@Result(name = "success", location = "XXXXXXXXX"),
			@Result(name = "fail", location = "XXXXXXX") })
	public String initialization() throws Exception {
    ................................................
 }
}