我有一個Java Servlet後端,數據存儲連接到我的應用程序;我試圖使用Android Studio LoginActivity模板實現一個使用用戶的電子郵件和密碼(不是PlusBaseActivity處理Google帳戶登錄)的登錄系統,但我不知道如何從這裏開始:自定義用戶在AppEngine中登錄
如何才能你說用戶已登錄?以及如何持久使用我的數據存儲庫?我在這裏讀到:How to login User using UserService on AppEngine Java,我只需要調用該方法resp.sendRedirect(userService.createLoginURL(req.getRequestURI()))
,我已經這樣做了:
@Override
public void doPost(HttpServletRequest req, HttpServletResponse resp) throws IOException {
int size = checkDatastore(); // 0 if empty, > 0 if not empty
if(size==0){
populateDatastore();
}
String asyncMessage = req.getParameter("order");
if(asyncMessage.equals("login")){
mail = req.getParameter("email");
psw = req.getParameter("password");
UserService userService = UserServiceFactory.getUserService();
User user = userService.getCurrentUser();
String message="";
resp.setContentType("text/plain");
PrintWriter out = resp.getWriter();
if(user == null) {
//Sends a temporary redirect response to the client using the
// specified redirect location URL and clears the buffer.
String uri = userService.createLoginURL(req.getRequestURI());
resp.sendRedirect(uri);
User user1 = userService.getCurrentUser();
message="No one is logged in!\n" + "Sent from App Engine at " + new Date();
out.println(message);
out.flush();
}if(user !=null) {
// login(user);
message = "Hello, " + user.getEmail() +
", "+user.getNickname()+"!" + "\nSent from App Engine at "+ new Date();
out.println(message);
out.flush();
}
}
}
但sendRedirect()
方法只給了我一個URI。做什麼的?
此外,User user = userService.getCurrentUser()
總是返回null
。怎麼來的?