action不能往jsp中传递数据的问题

struts中一个action的配置如下: action 中部分源代码: public ActionForward list(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) { log.debug(“list library “); List list = libraryManagerService.listLibrarys(); if(list == null) log.debug(“there is not any library ,because list is null”); else log.debug(“there are “ + list.size() + “ librarys .”); request.setAttribute(“list”, list) ; // request.getSession().setAttribute(“list”, list); return mapping.findForward(“listLibrarys”); } jsp中部分源代码: ${library.code} ${library.name} ${library.buildTime} “>添加 “>修改 “>删除 问题: 一次也不能循环. 在action的 List list = libraryManagerService.listLibrarys();后中加入: log.debug(“list size=”+list.size()); 运行结果:list size=6. 原因是: 中的redirect=”true”.直接转向后.request中的数据丢失. 改为redirect=”false”即可. redirect 决定了action在使用forward跳转的时候是使用 RequestDispatcher rd = getServletContext().getRequestDispatcher(uri).forward(request, response); 还是 response.sendRedirect(response.encodeRedirectURL(uri)); 在structs的类RequestProcessor中processForwardConfig方法里面有如下代码： if(forward.getRedirect())//判断redirect是否为true { if(uri.startsWith(“/“)) uri = request.getContextPath() + uri; response.sendRedirect(response.encodeRedirectURL(uri)); } else { doForward(uri, request, response); } 其中的方法doForward如下： protected void doForward(String uri, HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException { RequestDispatcher rd = getServletContext().getRequestDispatcher(uri); if(rd == null) { response.sendError(500, getInternal().getMessage(“requestDispatcher”, uri)); return; } else { rd.forward(request, response); return; } 这两种跳转方法的区别是： forward 会将 request state , bean 等等信息带往下一个 jsp redirect 是送到 client 端后，再由client向服务器发送request,服务器接收到后来发的request中已经不包含上次的request的state，bean等信息了。所以在jsp中就接收不到相应的数据