HttpServletRequest request = ServletActionContext.getRequest();为null的问题

Posted 2023-03-21

这是一个普通的java类，不是Action。
HttpServletRequest request = ServletActionContext.getRequest();
request.setAttribute("", "");
System.out.println(request+"----");
HttpSession session = request.getSession();
System.out.println(session+"++++");

这段代码开始用的时候很好，但是当我把调用 这段代码中的方法的 那个jsp放到frameset中后，request就为null了，当然后面的session也就为null了，MyEclipse中报错的是HttpSession session = request.getSession();这一行空指针异常，请问是咋搞的呢？

参考技术A request已经为null了 null.getSession.你想想会报空指针异常吗？ 肯定会报。request取值只能取到上一操作存的request的value 如果没有就是空。 必然你用request。getSession也就为空了

参考资料：如果您的回答是从其他地方引用，请表明出处

过滤器输出返回值

 

 

    private void returnJson(HttpServletRequest request,ServletResponse response, ResultModel ResultModel) throws IOException 
        //把返回值输出到客户端
        HttpServletRequest httpServletRequest = (HttpServletRequest) request;
        HttpServletResponse httpServletResponse = (HttpServletResponse) response;
        httpServletResponse.setHeader("Access-control-Allow-Origin", httpServletRequest.getHeader("Origin"));
        httpServletResponse.setHeader("Access-Control-Allow-Methods", "GET,POST,OPTIONS,PUT,DELETE");
        httpServletResponse.setHeader("Access-Control-Allow-Headers", httpServletRequest.getHeader("Access-Control-Request-Headers"));
        response.setContentType("application/json; charset=utf-8");
        response.setCharacterEncoding("UTF-8");
        ServletOutputStream outputStream = response.getOutputStream();
        outputStream.write(JsonTools.objToJson(ResultModel).getBytes());
        outputStream.flush();
        outputStream.close();