I have a server running in Java using Eclipse (Here the full code):
public class Main {
public static void main(String[]args) {
// BBDD connection var
Connection con = null;
// Sockets
ServerSocket server = null;
try {
server = new ServerSocket(5010);
} catch (IOException e2) {System.out.println("Error at creating server, check if the port is in use");System.exit(-1);}
/*** MySQL driver loading***/
try {
Class.forName("com.mysql.jdbc.Driver");
System.out.println("MySQL driver is UP");
} catch (ClassNotFoundException e1) {System.out.println("Error loading MySQL driver");}
/*** Stablishing connection with the ddbb ***/
try {
con= (Connection) DriverManager.getConnection("jdbc:mysql://IP/Database", "username", "password");
System.out.println("Connection stablished");
} catch (SQLException e) {
System.out.println("SQL ERROR");
e.printStackTrace();
}
/*** Assigning thread for client ***/
System.out.println("Listening for new requests...");
while (true) {
try {
Socket clientSocket;
clientSocket = server.accept();
System.out.println("Connection stablished");
DataInputStream dis = new DataInputStream(clientSocket.getInputStream());
DataOutputStream dos = new DataOutputStream(clientSocket.getOutputStream());
ThreadForClient client = new ThreadForClient(con, clientSocket, dis, dos);
Thread thread = new Thread(cliente);
thread .start();
} catch (IOException e) {System.out.println("Error making client socket");}
}
}
class ThreadForClient implements Runnable {
Connection con;
Socket clientSocket;
DataInputStream dis;
DataOutputStream dos;
public ThreadForClient(Connection con, Socket s, DataInputStream dis, DataOutputStream dos) {
this.con = con;
this.clientSocket = s;
this.dis = dis;
this.dos = dos;
}
@Override
public void run() {
try {
int opc = dis.readInt();
switch (opc) {
case 1:
String email = dis.readUTF();
Boolean result = existeUsuario(email);
dos.writeBoolean(result);
break;
default: break;
}
} catch (Exception e) {
e.printStackTrace();
}
}
public Boolean userExists(String email) throws SQLException { // 1
email = email.toLowerCase();
Statement stmt;
stmt = con.createStatement();
ResultSet rs=stmt.executeQuery("select * from users where email = '"+email+"'");
boolean result = rs.first();
return result;
}
}
As you can see, the client sends 2 values and receives 1, the first one is for the switch, which will indicate what to exceute, for now I just have on option (checking if email exists in the ddbb), the second value is the email as the code has already entered the switch.
The server is fully working and I already tested it with a Client Test project in Eclipse (It is what I want to do in Android Studio):
public static void main(String[] args) {
Socket socket = null;
try {
socket = new Socket(HOST, PORT);
System.out.println("Conection succesful");
DataOutputStream dos;
DataInputStream dis;
dos = new DataOutputStream(socket.getOutputStream());
dis = new DataInputStream(socket.getInputStream());
dos.writeInt(1);
dos.writeUTF("email@example.com");
Boolean bool = dis.readBoolean();
if (bool) {
System.out.println("Email exists in the BBDD.");
} else {
System.out.println("Email does not exist in the BBDD.");
}
socket.close();
} catch (Exception e) {System.out.println("Server connection failed");}
}
Now what I want to do is doing the same client in Android Studio so it can connect to the server.
I tried this:
public class SocketConnection {
UserExists ue;
public SocketConnection() throws IOException {
connect();
}
public void connect() {
ue = new UserExists();
ue.execute();
}
}
class UserExists extends AsyncTask<Void, Void, Void> {
int PORT = 5010;
String HOST = "192.168.1.5";
private Socket socket;
private DataOutputStream dos;
private DataInputStream dis;
@Override
protected Void doInBackground(Void... voids) {
try {
socket = new Socket(HOST, PORT);
dos = new DataOutputStream(socket.getOutputStream());
dis = new DataInputStream(socket.getInputStream());
} catch (Exception e) {
System.out.println("Socket error");
e.printStackTrace();
}
return null;
}
@Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
}
}
When I run it it does not give me any error but if I log the socket value at doInBackground's bottom to see the socket value, it says it is null.
I also tried using Thread and Handle but I can't get the result the server gives me back to the main thread.
