BufferedReader readLine（）方法沒有多次運行，Java，Socket，線程

Question

我正在做一個學校項目，我的小組已經提出了終端web messenger應用程序的主題（類似於whatsapp，絕對不那麼複雜）。我的問題是我的BufferedReader對象在收到客戶端的下一個輸入後不會讀取下一個輸入。我第一次向服務器發送信息BufferedReader的作品，但隨後沒有任何反應。我能做些什麼來解決這個問題？我是Threads和Sockets的新手，所以請回答假設我幾乎什麼都不知道。先謝謝你。 （PS。如果我很想念我的任何細節的代碼，請務必讓我知道，我會盡快得到消息添加更多）

客戶端主：

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); 
    } 
} 
} 

服務器線程：

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

而不必運行它自己，我要去猜那是因爲你使用的嘗試，與資源循環您BufferedReader S的。當您關閉BufferedReader時，您還將關閉底層流，這意味着您的套接字（以及您的連接）將被關閉。

也許，而不是在每個方法調用中爲您的輸入流打開一個新的BufferedReader，並在您的輸出流中打開一個新的PrintWriter，或許它們應該在套接字旁邊是全局的？要麼是這樣，要麼就是不要在這種情況下使用試用資源。