从不同的活动在同一个会话中执行多个请求
Do multiple requests in the same session from different Activities
我最近尝试开发一个 servlet，然后将它连接到我的 android 应用程序，但我无法让它正常工作。
这是我的登录 servlet
@WebServlet(name = "login", value = "/auth/login")
public class AuthUser extends HttpServlet {
private Gson gson = new Gson();
public void init() {
Dao.registerDriver();
}
public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
response.setContentType("application/json");
response.setCharacterEncoding("UTF-8");
String id = request.getParameter("id");
String psw = request.getParameter("psw");
HttpSession s = request.getSession();
PrintWriter out = response.getWriter();
HashMap<String, Object> responseJson = new HashMap<>();
Student student;
if(id != null && psw != null) {
student = FetchFromDB.fetchStudentData(id);
if (student != null && student.getPassword().equals(psw)) {
s.setAttribute("username", student.getNumber());
s.setAttribute("surname", student.getSurname());
s.setAttribute("role", student.getRole());
responseJson.put("id", request.getSession().getId());
responseJson.put("user", student);
responseJson.put("message", "Logged succesfully");
out.print(new Gson().toJson(responseJson));
} else {
responseJson.put("message", "The mail or the username is not correct, please try again");
out.println(new Gson().toJson(responseJson));
}
} else {
responseJson.put("message", "The mail or username value is null, check that out");
}
out.flush();
}
public void destroy() {
}
}
我从 android 应用程序的登录页面调用此 servlet，如下所示：
private void login() throws MalformedURLException {
RequestQueue queue = Volley.newRequestQueue(this);
String username = usernameText.getText().toString();
String psw = passwordText.getText().toString();
String url = Costants.URL + "auth/login?id="+username+"&psw="+psw+"";
JsonObjectRequest jsonObjReq = new JsonObjectRequest(Request.Method.GET,
url,
null,
response -> {
Log.d("In onResponse", ""+response);
try {
Log.d("In callServer", "Object returned: " +response.toString());
intent.putExtra("key-username", usernameText.getText().toString());
intent.putExtra("key-role", response.getJSONObject("user").getString("role"));
intent.putExtra("key-surname", response.getJSONObject("user").getString("surname"));
intent.putExtra("key-session-id", response.getString("id"));
startActivity(intent);
} catch (JSONException e) {
e.printStackTrace();
}
}, error -> {
VolleyLog.d("In onErrorResponse", "Error: " + error.getMessage());
Toast.makeText(getApplicationContext(),
error.getMessage(), Toast.LENGTH_SHORT).show();
});
// Access the RequestQueue through your singleton class.
MySingleton.getInstance(getApplicationContext()).addToRequestQueue(jsonObjReq);
}
当我点击登录按钮时，它会正常工作，因此它会与 servlet 通信，并且主程序 activity 会正常启动。
但是当我尝试从我的 MainActivity 进行另一个调用时，将无法识别 servlet 中的会话，因此用户显示为未知，这是 mainActivity 的代码。
public class MainActivity extends AppCompatActivity {
private ActivityMainBinding binding;
String usernameOfLoggedUser;
String surnameOfLoggedUser;
String roleOfLoggedUser;
String sessionId;
Bundle extras;
private UserViewModel viewModel;
private BookedLessonsViewModel bookedLessonsViewModel;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
extras = getIntent().getExtras();
usernameOfLoggedUser = extras.getString("key-username", "NoValue");
surnameOfLoggedUser = extras.getString("key-surname", "NoValue");
roleOfLoggedUser = extras.getString("key-role", "NoValue");
sessionId = extras.getString("key-session-id", "NoValue");
showWelcomeToast(usernameOfLoggedUser);
setViewModelUser(usernameOfLoggedUser, roleOfLoggedUser, surnameOfLoggedUser);
fetchBookedLessons(usernameOfLoggedUser);
setupUIElements();
}
/**
* Fetch lessons from db and set the model view for the lessons booked
* @param username
*/
private void fetchBookedLessons(String username) {
String url = Costants.URL + "book/bookedLessonsForUser";
ArrayList<BookedLesson> bookedLessons = new ArrayList<>();
CustomRequest jsonCustomReq = new CustomRequest(
Request.Method.GET,
url,
null,
sessionId,
new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
Log.d("in onResponse", response.toString());
// int i = 0;
// try {
// JSONArray reservations = response.getJSONArray("reservations");
// while(i < reservations.length()) {
// JSONObject reservation = reservations.getJSONObject(i);
// String idUser = reservation.getString("idUser");
// String idTeacher = reservation.getString("idTeacher");
// String subject = reservation.getString("nameSubject");
// String day = reservation.getString("day");
// String slot = reservation.getString("slot");
// String status =reservation.getString("status");
//
// BookedLesson bookedLesson = new BookedLesson(idUser, idTeacher, slot, subject, day, status);
// bookedLessons.add(bookedLesson);
// i++;
// }
// } catch (JSONException e) {
// e.printStackTrace();
// } finally {
// setViewModelLessons(bookedLessons);
// }
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
}
);
MySingleton.getInstance(getApplicationContext()).addToRequestQueue(jsonCustomReq);
}
private void showWelcomeToast(String username) {
Toast toast = Toast.makeText(getApplicationContext(), "You are logged as: " + username, Toast.LENGTH_SHORT*2);
toast.show();
}
@Override
protected void onResume() {
super.onResume();
fetchBookedLessons(usernameOfLoggedUser);
}
private void setupUIElements() {
binding = ActivityMainBinding.inflate(getLayoutInflater());
setContentView(binding.getRoot());
BottomNavigationView navView = findViewById(R.id.nav_view);
// Passing each menu ID as a set of Ids because each
// menu should be considered as top level destinations.
AppBarConfiguration appBarConfiguration = new AppBarConfiguration.Builder(
R.id.navigation_home, R.id.navigation_dashboard, R.id.navigation_notifications)
.build();
NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment_activity_main);
NavigationUI.setupActionBarWithNavController(this, navController, appBarConfiguration);
NavigationUI.setupWithNavController(binding.navView, navController);
}
/**
* Set the model view for the user so that every fragment has the data for the logged user
* @param usernameOfLoggedUser
* @param roleOfLoggedUser
* @param surnameOfLoggedUser
*/
private void setViewModelUser(String usernameOfLoggedUser, String roleOfLoggedUser, String surnameOfLoggedUser) {
viewModel = new ViewModelProvider(this).get(UserViewModel.class);
viewModel.setUser(usernameOfLoggedUser);
viewModel.setRole(roleOfLoggedUser);
viewModel.setSurname(surnameOfLoggedUser);
viewModel.getUser().observe(this, username -> {
Log.d("In onCreate", "Share data: " + username);
});
}
/**
* Pass the array fetched and set the model view for the lessons
* @param lessons
*/
private void setViewModelLessons(ArrayList<BookedLesson> lessons) {
bookedLessonsViewModel = new ViewModelProvider(this).get(BookedLessonsViewModel.class);
bookedLessonsViewModel.setBookedLessons(lessons);
bookedLessonsViewModel.getBookedLessons().observe(this, bookedLessons -> {
Log.d("In getBookedLessons", "Lessons: " + bookedLessons.size());
});
}
}
但我在 return 中得到这个值：
-26 13:48:47.053 12225-12225/com.example.bookinglessons D/in onResponse: {"message":"you're not logged"}
如果您知道发生了什么，那将非常有帮助，在此先感谢。
我找到了解决此类问题的方法。
您只需要在第一个 Activity（在我的例子中是 MainActivity）的 onCreate 中添加这些行。
CookieManager cookieManager = new CookieManager();
CookieHandler.setDefault(cookieManager);
这解决了我的问题并维护了会话。
我最近尝试开发一个 servlet，然后将它连接到我的 android 应用程序，但我无法让它正常工作。 这是我的登录 servlet
@WebServlet(name = "login", value = "/auth/login")
public class AuthUser extends HttpServlet {
private Gson gson = new Gson();
public void init() {
Dao.registerDriver();
}
public void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException {
response.setContentType("application/json");
response.setCharacterEncoding("UTF-8");
String id = request.getParameter("id");
String psw = request.getParameter("psw");
HttpSession s = request.getSession();
PrintWriter out = response.getWriter();
HashMap<String, Object> responseJson = new HashMap<>();
Student student;
if(id != null && psw != null) {
student = FetchFromDB.fetchStudentData(id);
if (student != null && student.getPassword().equals(psw)) {
s.setAttribute("username", student.getNumber());
s.setAttribute("surname", student.getSurname());
s.setAttribute("role", student.getRole());
responseJson.put("id", request.getSession().getId());
responseJson.put("user", student);
responseJson.put("message", "Logged succesfully");
out.print(new Gson().toJson(responseJson));
} else {
responseJson.put("message", "The mail or the username is not correct, please try again");
out.println(new Gson().toJson(responseJson));
}
} else {
responseJson.put("message", "The mail or username value is null, check that out");
}
out.flush();
}
public void destroy() {
}
}
我从 android 应用程序的登录页面调用此 servlet，如下所示：
private void login() throws MalformedURLException {
RequestQueue queue = Volley.newRequestQueue(this);
String username = usernameText.getText().toString();
String psw = passwordText.getText().toString();
String url = Costants.URL + "auth/login?id="+username+"&psw="+psw+"";
JsonObjectRequest jsonObjReq = new JsonObjectRequest(Request.Method.GET,
url,
null,
response -> {
Log.d("In onResponse", ""+response);
try {
Log.d("In callServer", "Object returned: " +response.toString());
intent.putExtra("key-username", usernameText.getText().toString());
intent.putExtra("key-role", response.getJSONObject("user").getString("role"));
intent.putExtra("key-surname", response.getJSONObject("user").getString("surname"));
intent.putExtra("key-session-id", response.getString("id"));
startActivity(intent);
} catch (JSONException e) {
e.printStackTrace();
}
}, error -> {
VolleyLog.d("In onErrorResponse", "Error: " + error.getMessage());
Toast.makeText(getApplicationContext(),
error.getMessage(), Toast.LENGTH_SHORT).show();
});
// Access the RequestQueue through your singleton class.
MySingleton.getInstance(getApplicationContext()).addToRequestQueue(jsonObjReq);
}
当我点击登录按钮时，它会正常工作，因此它会与 servlet 通信，并且主程序 activity 会正常启动。 但是当我尝试从我的 MainActivity 进行另一个调用时，将无法识别 servlet 中的会话，因此用户显示为未知，这是 mainActivity 的代码。
public class MainActivity extends AppCompatActivity {
private ActivityMainBinding binding;
String usernameOfLoggedUser;
String surnameOfLoggedUser;
String roleOfLoggedUser;
String sessionId;
Bundle extras;
private UserViewModel viewModel;
private BookedLessonsViewModel bookedLessonsViewModel;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
extras = getIntent().getExtras();
usernameOfLoggedUser = extras.getString("key-username", "NoValue");
surnameOfLoggedUser = extras.getString("key-surname", "NoValue");
roleOfLoggedUser = extras.getString("key-role", "NoValue");
sessionId = extras.getString("key-session-id", "NoValue");
showWelcomeToast(usernameOfLoggedUser);
setViewModelUser(usernameOfLoggedUser, roleOfLoggedUser, surnameOfLoggedUser);
fetchBookedLessons(usernameOfLoggedUser);
setupUIElements();
}
/**
* Fetch lessons from db and set the model view for the lessons booked
* @param username
*/
private void fetchBookedLessons(String username) {
String url = Costants.URL + "book/bookedLessonsForUser";
ArrayList<BookedLesson> bookedLessons = new ArrayList<>();
CustomRequest jsonCustomReq = new CustomRequest(
Request.Method.GET,
url,
null,
sessionId,
new Response.Listener<JSONObject>() {
@Override
public void onResponse(JSONObject response) {
Log.d("in onResponse", response.toString());
// int i = 0;
// try {
// JSONArray reservations = response.getJSONArray("reservations");
// while(i < reservations.length()) {
// JSONObject reservation = reservations.getJSONObject(i);
// String idUser = reservation.getString("idUser");
// String idTeacher = reservation.getString("idTeacher");
// String subject = reservation.getString("nameSubject");
// String day = reservation.getString("day");
// String slot = reservation.getString("slot");
// String status =reservation.getString("status");
//
// BookedLesson bookedLesson = new BookedLesson(idUser, idTeacher, slot, subject, day, status);
// bookedLessons.add(bookedLesson);
// i++;
// }
// } catch (JSONException e) {
// e.printStackTrace();
// } finally {
// setViewModelLessons(bookedLessons);
// }
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
}
);
MySingleton.getInstance(getApplicationContext()).addToRequestQueue(jsonCustomReq);
}
private void showWelcomeToast(String username) {
Toast toast = Toast.makeText(getApplicationContext(), "You are logged as: " + username, Toast.LENGTH_SHORT*2);
toast.show();
}
@Override
protected void onResume() {
super.onResume();
fetchBookedLessons(usernameOfLoggedUser);
}
private void setupUIElements() {
binding = ActivityMainBinding.inflate(getLayoutInflater());
setContentView(binding.getRoot());
BottomNavigationView navView = findViewById(R.id.nav_view);
// Passing each menu ID as a set of Ids because each
// menu should be considered as top level destinations.
AppBarConfiguration appBarConfiguration = new AppBarConfiguration.Builder(
R.id.navigation_home, R.id.navigation_dashboard, R.id.navigation_notifications)
.build();
NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment_activity_main);
NavigationUI.setupActionBarWithNavController(this, navController, appBarConfiguration);
NavigationUI.setupWithNavController(binding.navView, navController);
}
/**
* Set the model view for the user so that every fragment has the data for the logged user
* @param usernameOfLoggedUser
* @param roleOfLoggedUser
* @param surnameOfLoggedUser
*/
private void setViewModelUser(String usernameOfLoggedUser, String roleOfLoggedUser, String surnameOfLoggedUser) {
viewModel = new ViewModelProvider(this).get(UserViewModel.class);
viewModel.setUser(usernameOfLoggedUser);
viewModel.setRole(roleOfLoggedUser);
viewModel.setSurname(surnameOfLoggedUser);
viewModel.getUser().observe(this, username -> {
Log.d("In onCreate", "Share data: " + username);
});
}
/**
* Pass the array fetched and set the model view for the lessons
* @param lessons
*/
private void setViewModelLessons(ArrayList<BookedLesson> lessons) {
bookedLessonsViewModel = new ViewModelProvider(this).get(BookedLessonsViewModel.class);
bookedLessonsViewModel.setBookedLessons(lessons);
bookedLessonsViewModel.getBookedLessons().observe(this, bookedLessons -> {
Log.d("In getBookedLessons", "Lessons: " + bookedLessons.size());
});
}
}
但我在 return 中得到这个值：
-26 13:48:47.053 12225-12225/com.example.bookinglessons D/in onResponse: {"message":"you're not logged"}
如果您知道发生了什么，那将非常有帮助，在此先感谢。
我找到了解决此类问题的方法。 您只需要在第一个 Activity（在我的例子中是 MainActivity）的 onCreate 中添加这些行。
CookieManager cookieManager = new CookieManager();
CookieHandler.setDefault(cookieManager);
这解决了我的问题并维护了会话。