我有一个多线程tcp服务器，可以处理多个客户端。 每个客户端都在服务器端具有保持套接字连接的线程。 理论上一切都可以正常工作很多分钟，但在极少数情况下，当连接多个客户端时，会发生以下情况： 其中一个客户端向服务器发送tcp数据包，服务器端读取超时。我发现了许多问题，解决了客户端的读取超时问题，但就我而言，这种情况从未发生过。就我而言，当从客户端接收数据包时，服务器会在读取时超时。 我的问题是，为什么以及如何发生这种情况，我该怎么做才能解决这个问题呢？
这是我的服务器监听器：
public class GameServerTCP extends Thread {
//TCP
private ServerSocket serverSocket;
public Server server;
public int amountOfTCPConnections = 0;
ClassLoader classLoader = getClass().getClassLoader();
File myFile = new File(classLoader.getResource("Sprites/sprite_sheet.png").getFile());
public GameServerTCP(Server game) {
this.server = game;
//TCP
try {
serverSocket = new ServerSocket(6336);
} catch (IOException e) {
e.printStackTrace();
}
}
public void run() {
while(true) {
//TCP
Socket socket = null;
try {
socket = serverSocket.accept();
Toolkit.getDefaultToolkit().beep();
System.out.println(socket.getRemoteSocketAddress() + " has connected to server.");
}
catch (Exception e) {
e.printStackTrace();
}
new TCPConnection(socket, this);
amountOfTCPConnections++;
if (amountOfTCPConnections > 500) {
System.err.println("Too many clients error! (unsolved)");
server.frame.dispatchEvent(new WindowEvent(server.frame, WindowEvent.WINDOW_CLOSING));
}
}
}
}
这是我的服务器线程，用于保存每个连接：
public class TCPConnection implements Runnable {
Socket socket;
private Thread thread;
private boolean isRunning = false;
public GameServerTCP serverTCP;
private String gamename = "-1";
public String username;
/**
* This is the future!
* Contains an exact imprint of the player of client side.
* Cheats can be detected here.
*/
private PlayerMP playerMP;
String clientSentence;
TCPConnection(Socket socket, GameServerTCP serverTCP) {
this.socket = socket;
this.serverTCP = serverTCP;
isRunning = true;
thread = new Thread(this);
thread.start();
}
public synchronized void closeConnection() {
if (MasterConnections.connectionsTCP.containsKey(getUniqueConnectionIdentifier())) MasterConnections.connectionsTCP.remove(getUniqueConnectionIdentifier());
if (this.username != null && MasterConnections.currentlyLoggedOnAccounts.contains(this.username)) MasterConnections.currentlyLoggedOnAccounts.remove(this.username);
if (this.gamename != null && serverTCP.server.games.containsKey(this.gamename)) {
Level game = serverTCP.server.games.get(this.gamename);
for (String p : game.playersInLevel) {
if (p.equals(getUniqueConnectionIdentifier())) {
game.playersInLevel.remove(p);
System.out.println(this.username + " has been been removed from game " + this.gamename + ".");
}
}
PacketTCP02LeaveGame tellOthersPacket = new PacketTCP02LeaveGame(this.gamename, this.username);
game.writeDataTCPToAllPlayersInThisLevel(tellOthersPacket);
}
try {
this.socket.close();
} catch (IOException e) {
e.printStackTrace();
}
System.out.println(socket.getRemoteSocketAddress() + " has been disconnected from server.");
this.serverTCP.amountOfTCPConnections--;
this.stop();
}
public String getUniqueConnectionIdentifier() {
return socket.getInetAddress() + ":" + socket.getPort();
}
public String generateUniqueUDPConnectionIdentifier(InetAddress inetAddess, int udpPort) {
System.out.println("uuc created: ");
System.out.println(inetAddess + "/" + udpPort);
return inetAddess + ":" + udpPort;
}
public void run() {
//version check first
PacketTCP00VersionCheck packetVersionCheck = new PacketTCP00VersionCheck(serverTCP.server.getVersion());
if (MasterConnections.connectionsTCP.containsKey(getUniqueConnectionIdentifier())) {
this.closeConnection();
}
else {
MasterConnections.connectionsTCP.put(getUniqueConnectionIdentifier(), this);
packetVersionCheck.writeData(this);
}
BufferedReader inFromClient;
try {
inFromClient = new BufferedReader(new InputStreamReader(socket.getInputStream()));
} catch (IOException e1) {
e1.printStackTrace();
closeConnection();
return;
}
while(isRunning) {
try {
clientSentence = inFromClient.readLine();
if (clientSentence == null) {
inFromClient.close();
closeConnection();
}
else {
System.out.println("tcprec -> " + (new Date(System.currentTimeMillis())) + " -> " + this.username + " -> " + clientSentence);
this.parsePacket(clientSentence.getBytes());
}
}
catch (SocketTimeoutException ste) {
/**
* TODO:
*/
ste.printStackTrace();
System.err.println("YOU CAN DO SOMETHING HERE!!!!!!!");
closeConnection();
}
catch (Exception e) {
e.printStackTrace();
closeConnection();
}
}
}
public void stop() {
isRunning = false;
try {
thread.join();
}
catch (InterruptedException e) {
e.printStackTrace();
}
}
}
这是我的客户：
public class GameClientTCP extends Thread {
public String gamestate = "logged out";
private Game game;
public Socket tcpSocket;
public boolean isRunning = false;
private String serverSentence;
public boolean hasBeenStarted = false;
public int boundUDPPort = -1;
public static String[] characters = new String[5];
public static boolean charactersAreLoaded = false;
private PrintWriter toServer;
public GameClientTCP(Game game, String ipAddress) {
this.game = game;
}
public boolean tryConnect() {
try {
tcpSocket = new Socket();
tcpSocket.connect(new InetSocketAddress(Settings.SERVER_ADDRESS, 6336), 1000);
System.out.println("Just connected to " + tcpSocket.getRemoteSocketAddress());
game.getSocketClientUDP().prepareBeforeStart();
game.getSocketClientUDP().start();
return true;
} catch (UnknownHostException e1) {
try {
tcpSocket.close();
} catch (IOException e) {
GameError.appendToErrorLog(e);
return false;
}
return false;
} catch (IOException e1) {
try {
tcpSocket.close();
} catch (IOException e) {
GameError.appendToErrorLog(e);
return false;
}
GameError.appendToErrorLog(e1);
return false;
}
}
public void run() {
BufferedReader fromServer;
try {
fromServer = new BufferedReader(new InputStreamReader(tcpSocket.getInputStream()));
toServer = new PrintWriter(tcpSocket.getOutputStream(),true);
} catch (IOException e1) {
GameError.appendToErrorLog(e1);
return;
}
while(isRunning) {
try {
serverSentence = fromServer.readLine();
//System.out.println("Received: " + serverSentence);
if (serverSentence != null) this.parsePacket(serverSentence.getBytes());
}
catch(UnknownHostException ex) {
GameError.appendToErrorLog(ex);
}
catch(IOException e){
GameError.appendToErrorLog(e);
}
catch(Exception e) {
GameError.appendToErrorLog(e);
}
}
}
public void sendMessageToServer(String message) {
try {
toServer.println(message);
toServer.flush();
}
catch (Exception e) {
GameError.appendToErrorLog(e);
System.exit(-1);
}
}
}
我希望了解更多有关此问题的信息，请帮忙！ ：）
编辑：可能很重要的是，当我的程序运行时，可能会发生，在较长的时间段内没有发送tcp数据包。超时总是发生，当我不发送任何数据包至少20或30分钟，然后当我再次发送一个，另一个客户端超时。
答案 0 :(得分：1)
事实证明，使用时间超过一定时间的tcp套接字会被同行破坏，从而失去连接。 我解决了我的问题，通过每分钟发送一个几乎空的tcp数据包，使所有程序和服务清楚，这些套接字是活着的！