BufferedReader readLine() -Methode nicht mehrfach ausgeführt, Java, Socket, Threads

Question

Ich mache ein Schulprojekt, das Thema meiner Gruppe hat Terminal Web Messenger App vorgeschlagen (ähnlich wie WhatsApp, definitiv weniger komplex). Mein Problem ist, dass mein BufferedReader Objekt die nächste Eingabe vom Client nicht liest, nachdem es empfangen wurde. Das erste Mal, dass ich Informationen an den Server sende, funktioniert die BufferedReader aber jederzeit danach passiert nichts. Was kann ich tun, um das zu beheben? Ich bin neu zu Threads und Sockets so bitte antworten, vorausgesetzt, ich weiß fast nichts. Vielen Dank im Voraus. (. PS Wenn ich einen Code in meinem Detail bin fehlt, stellen Sie sicher, mich zu informieren, und ich werde mehr hinzufügen, sobald ich die Meldung)

Client-Main:

package COE528.MajorProject; 

import java.io.BufferedReader; 
import java.io.IOException; 
import java.io.InputStreamReader; 
import java.io.PrintWriter; 
import java.net.Socket; 

public class ClientUIManager { 
private Client user = null; 
private Socket userSocket = null; 
private BufferedReader serverScannerInput, scanner = null; 
private PrintWriter output = null; 


public static ClientUIManager instance; 

private ClientUIManager(){ 
    try{ 
     userSocket = new Socket("localhost", 4000); 
     serverScannerInput = new BufferedReader(new InputStreamReader(userSocket.getInputStream())); 
     output = new PrintWriter(userSocket.getOutputStream(), true); 
     scanner = new BufferedReader(new InputStreamReader(System.in)); 
    }catch(IOException ex){ 
     ex.printStackTrace(); 
    } 
} 

public static ClientUIManager getInstance(){ 
    if(instance == null) 
     instance = new ClientUIManager(); 
    return instance; 
} 

public static void main(String[] args) { 
    instance = ClientUIManager.getInstance(); 
    try{ 
    String userInput; 
    String[] breakUp; 
    String serverInput; 
    System.out.println("Type \"login\" to login or \"create\" to create a new account "); 
    while(!((userInput = instance.scanner.readLine()).equals("/exit"))){ 
     System.out.println("userInput: " + userInput); //GET RID OF LATER 
     breakUp = userInput.split(" "); 
     //establish connection and respond acordingly 
     if(userInput.equals("login")){ 
      System.out.println("Please enter login information: \"Username Password\" "); 
      userInput = instance.scanner.readLine(); 
      instance.login(userInput); 
     } 
     if(userInput.equals("create")){ 
      System.out.println("Please create new account information: \"Login Password\" "); 
      userInput = instance.scanner.readLine(); 
      instance.createClient(userInput); 
     } 
     if(instance.userLoggedIn()){ 
      //private messaging 
      if(userInput.charAt(0)== '@'){ 
       if(breakUp.length > 1) 
        instance.privateMessage(userInput); 
       else 
        System.out.println("Not enough agruments please enter @Username message"); 
      } 
      if(breakUp[0].equals("/add")){ 
       if(breakUp.length ==2) 
        instance.addFriend(breakUp[1]); 
       else 
        System.out.println("Not enough agruments please enter a new command"); 
      } 
      if(breakUp[0].equals("/unfriend")){ 
       instance.removeFriend(breakUp[1]); 
      } 
     } 
    } 
    instance.output.println("/exit"); 
    System.out.println("Closing program"); 
}catch(IOException ex){ 
     ex.printStackTrace(); 
     System.exit(1); 
    } 
} 

public boolean userLoggedIn(){ 
    //OVERVIEW: checks if user has logged in or not. 
    if(user == null) 
     return false; 
    else 
     return true; 
} 

public void privateMessage(String previousInput){ 
    //OVERVIEW: sends private message to another user (name inside string). Checks checkPersonOnline first: true sends message/false responds with message telling recipient is offline 
    String checkUsername; 
    String[] checkUsernameArray; 
    checkUsernameArray = previousInput.split(" "); 
    checkUsername = checkUsernameArray[0]; 
    checkUsername = checkUsername.replace("@", ""); 
    if(checkPersonOnline(checkUsername)) 
     output.println(previousInput); 
    else 
     System.out.println(checkUsername + " is offline, message not sent"); 
} 

public boolean checkPersonOnline(String username){ 
    boolean check = false; 
    output.println("/check "+ username); //send command to check with the username 
    try{ 
     if(serverScannerInput.readLine().equals("true")) 
      check = true; 
    }catch(IOException ex){ 
     ex.printStackTrace(); 
    } 
    return check; 
} 
public boolean checkPersonExists(String username){ 
    boolean check = false; 
    String serverInput; 
    try(BufferedReader serverScannerInput = new BufferedReader(new InputStreamReader(userSocket.getInputStream())); 
     PrintWriter outputToServer = new PrintWriter(userSocket.getOutputStream(), true); 
     ){ 
     outputToServer.println("/exists "+username); 
     serverInput = serverScannerInput.readLine(); 
     System.out.println("Server responded "+serverInput); 
     if(serverInput.equals("true")) 
      check = true; 
     else 
      check = false; 
    }catch(IOException ex){ 
     ex.printStackTrace(); 
    } 
    return check; 
} 
public void addFriend(String username){ 
    //OVERVIEW: takes a username, checks if person exists, checks if person is in client's friendsList, adds username to persons friendsList 
    //Check if person exists 
    if(checkPersonExists(username)){ 
     //check if person is in friends list. If false: add person to friendsList. If true: display's: "This person is in your friendsList already" 
     if(!user.checkFriends(username)){ 
      output.println("/add" + username); 
     }else{ 
      System.out.println("This person is already in your friends list"); 
     } 
    }else{ 
     System.out.println(username +" does not exist, please enter new command"); 
    }   
} 

public void removeFriend(String username){ 
    //Checks if username is in client's friends List, sends remove command to server 
    if(user.checkFriends(username)) 
     output.println("/remove "+username); 
    else 
     System.out.println(username+ " is not in your friends list, please enter new command"); 
} 

public void createClient(String previousInput){ 
    System.out.println("createClient method started");   
    try(   
     BufferedReader serverScannerInput = new BufferedReader(new InputStreamReader(userSocket.getInputStream())); 
     PrintWriter outputToServer = new PrintWriter(userSocket.getOutputStream(), true); 
     ){ 
     String userInput = previousInput; 
     String[] breakUp = userInput.split(" "); 
     String serverInput; 
     while(breakUp.length != 2){ 
      System.out.println("Missing argument please re-enter login"); 
      userInput = scanner.readLine(); 
      breakUp = userInput.split(" "); 
      if(userInput.equals("exit")){ //Re-check to see if you need this 
       System.out.println("closing program"); 
       System.exit(1); 
      } 
     } 
     //Checks if the user exists or not 
     if(!this.checkPersonExists(userInput)){ 
      //Sends commands to create user 
      System.out.println("/create sent"); 
      outputToServer.println("/create " +userInput); 
      output.flush(); 
     }else{ 
      System.out.println("The name you have entered has already been created please choose another command"); 
     } 
     System.out.println("new user created. Please login"); 
    }catch(Exception e){ 
     e.printStackTrace(); 
    } 
} 

public void login(String previousInput) { 
    try{ 
    String userInput = previousInput; 
    String[] breakUp = userInput.split(" "); 
    String serverInput; 
    System.out.println("please enter login: \"username password\" "); 
    while(breakUp.length != 2){ 
     System.out.println("Missing argument please re-enter login"); 
     userInput = scanner.readLine(); 
     breakUp = userInput.split(" "); 
     if(userInput.equals("exit")){ //Re-check to see if you need this 
      System.out.println("closing program"); 
      System.exit(1); 
     } 
    } 
    //Checks if user inputed correct login information(/login command): send user login together and is suppose to recieve "true" or "false" 
    output.println("/exists "+ userInput); 
    serverInput = serverScannerInput.readLine(); 
    while(serverInput.equals(false)){ 
     //place code for bad login 
     System.out.println("Invalid login"); 
     userInput = scanner.readLine(); 
     login(userInput); 
     serverInput = serverScannerInput.readLine(); 
    } 
    if(serverInput.equals("true")){ 
     //creates user 
     output.println("/login "+ userInput); 
     user = new Client(breakUp[0], breakUp[1]); 
     //user.changeStatus(); 
     output.println("/getFriendsList "+ breakUp[0]); //sends getFriendsList plus username 
     serverInput = serverScannerInput.readLine(); 
     breakUp = serverInput.split(" "); 
     for(int x = 0; x< breakUp.length; x++){ 
      instance.addFriend(breakUp[x]); 
     } 
    } 
}catch(IOException ex){ 
     ex.printStackTrace(); 
     System.exit(1); 
    } 
} 
} 

Server Thema:

package COE528.MajorProject; 

import java.net.Socket; 
import java.io.*; 
import java.net.ServerSocket; 


public class ServerThread extends Thread{ 
private final Socket client; 
private final ServerProtocol protocol; 

public ServerThread (Socket clientThread){ 
    client = clientThread; 
    protocol = new ServerProtocol(client); 
} 

@Override 
public void run(){ 
    System.out.println("Thread created"); //GET RID OF LATER 
    String inputLine=null; 
    String[] breakUp; 
    try(
      BufferedReader input = new BufferedReader(new InputStreamReader(client.getInputStream())); 
      PrintWriter output = new PrintWriter(client.getOutputStream(), true); 
      ){ 
     System.out.println("trying BufferedReader " + input.toString()); 
     inputLine = input.readLine(); 
     while(!inputLine.equals("/exit")){ 
      System.out.println("server recieved :" + inputLine); 
      breakUp = inputLine.split(" "); 
      if(breakUp[0].equals("/login")){ 
       protocol.login(breakUp[0]); 
      } 
      if(breakUp[0].equals("/create")){ 
       System.out.println("create started"); 
       StringBuilder foo = new StringBuilder(); 
       foo.append(breakUp[1]); 
       foo.append(breakUp[2]); 
       protocol.createClient(foo.toString()); 
      } 
      if(breakUp[0].equals("/exists")){ 
       protocol.checkForClientExists(breakUp[1]); 
      } 
      inputLine = input.readLine(); 
      System.out.println("reading next input: " + inputLine); 
     } 
     //input.close(); 
     //output.close(); 

     //closing of thread 
    }catch(IOException ex){ 

    } 
} 
} 

Answer 1

Ohne Lauf es selbst ist, werde ich es erraten, weil die Nutzung des Portals try-with-Ressourcen auf Ihrem BufferedReader s Schleifen. Wenn Sie eine BufferedReader schließen, schließen Sie auch den zugrunde liegenden Stream, was bedeutet, dass Ihr Socket (und damit Ihre Verbindung) geschlossen wird.

Vielleicht, anstatt eine neue BufferedReader für Ihren Eingangsstrom und eine neue PrintWriter für Ihren Ausgangsstrom bei jedem Methodenaufruf zu öffnen, sollten sie vielleicht direkt neben dem Sockel global sein? Entweder das, oder einfach in diesem Fall keine Try-with-Resources verwenden.