1、通過上下文，從ActionContext中獲取

ActionContext actionContext = ActionContext.getContext（）；
Map session = actionContext.getSession（）；

2、實現SessionAware介面

public class SessionTest1Action extends ActionSupport implements SessionAware {

private Map session;

public void setSession（Map session） {

this.session = session;

}

public class BaseAction extends ActionSupport{
    public HttpSession session;
    public HttpServletRequest request;
    public HttpSession getSession() {
        if(request==null){
            request=ServletActionContext.getRequest();
        }
        session=request.getSession();
        return session;
    }
    public HttpServletRequest getRequest() {
        request=ServletActionContext.getRequest();
        return request;
    }

}