javaweb Response重定向

public class RedirectServlet extends HttpServlet {
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
       resp.sendRedirect("/r/image");
       /*resp.setStatus(302);
       resp.setHeader("Location","/r/image");
        */
    }

<form action="${pageContext.request.contextPath}/zf" method="get">
    用户名:<input type="text" name="username">
    <br>
    密码:<input type="text" name="password">
    <br>
    <input type="submit">
</form>

 protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //处理请求
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        System.out.println(username+":"+password);
       //重定向时候一定要注意，路径问题，否则404
        resp.sendRedirect("/r/success.jsp");
    }