ServletRequest中的会话变量 [英] Session variables in ServletRequest

问题描述

我需要通过过滤器访问会话变量。我甚至不知道是否有可能。实际上，问题是来自 javax.Servlet.Filter 实现的 doFilter 方法类型是 ServletRequest ，而HttpServlet继承了类，doPost方法参数 request 是HttpServletRequest。

I need to access session variables through a filter. I don't even know if it is possible. In practice, the problem is that the doFilter method type from javax.Servlet.Filter implementation is ServletRequest, whilst HttpServlet inherited classes, doPost method parameter request is HttpServletRequest.

1. 我可以在过滤器中访问ServletRequest中的会话吗？


2. 我应该这样做吗？


3. 你能推荐我什么？

谢谢！

推荐答案

只需投射获得的 ServletRequest HttpServletRequest 。

Just cast the obtained ServletRequest to HttpServletRequest.

@Override
public void doFilter(ServletRequest req, ServletResponse res, FilterChain chain) throws IOException, ServletException {
    HttpServletRequest request = (HttpServletRequest) req;
    HttpSession session = request.getSession(false);
    // ...
}

参见：

• 我们的servlet过滤器维基页面



See also:

• Our servlet-filters wiki page

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