如何在Java Servlet中使用Session？ [英] How to use Session in Java Servlet?

问题描述

我在java代码中遇到会话问题。在通过post提交表单后，java servlet将确定验证码是否正确。我是否应该知道在java servlet中使用会话时应该添加的内容？有什么东西需要导入才能使用会话吗？

I am having issues with session in my java code. Upon submitting a form via post, the java servlet will determine if the captcha is correct. May I know anything that I should add to use the session in java servlet? Is there any thing that I need to import to use session?

protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
try{
    // Validate Captcha
    String userCaptcha = request.getParameter("captcha");
    Captcha captcha = (Captcha) session.getAttribute(Captcha.NAME);
    if (!captcha.isCorrect(userCaptcha)) {
        errorMsgs.add("Please input the correct Captcha value.");
    }
} catch (RuntimeException e) {
    ...
}
...

非常感谢。

推荐答案

您需要：

// create session if one doesn't exist
HttpSession session = request.getSession(true); 

您实际上并未在代码中的任何位置引用会话。

You're not actually referencing a session anywhere in your code.

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