一个简单的验证码小例子
jsp代码：
?生成验证码图片的servlet代码：
@WebServlet(urlPatterns="/login")public class Checknum extends HttpServlet{ @Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp)throws ServletException, IOException { String checknum=(String) req.getSession().getAttribute("randnum"); String imageCode= req.getParameter("imageCode"); if(checknum.equals(imageCode)){ resp.sendRedirect(req.getContextPath()+"/index.jsp"); }else{ resp.sendRedirect(req.getContextPath()+"/checknum.jsp"); } }}?
