redirect_uri 参数错误,求解决方案

Question

@WebServlet("/wxLogin") public class WXLoginServlet extends HttpServlet {     @Override     protected void doGet(HttpServletRequest req, HttpServletResponse resp)             throws ServletException, IOException {         String backUrl = "http://morning.iok.la/MEILI/callBack";// 回调地址         String url = "https://open.weixin.qq.com/connect/oauth2/authorize?appid="                 + AuthUtils.APPID                 + "&redirect_uri="                 + URLEncoder.encode(backUrl)                 + "&response_type=code&scope=snsapi_userinfo&state=STATE#wechat_redirect";         resp.sendRedirect(url);     }