Java TCP多線程問題

Question

我的程序運行正常，許多用戶可以連接並向服務器發送命令。 但是，當用戶使用命令向服務器發送垃圾郵件時，該服務器將阻止所有其他客戶端，並且該服務器不會收到來自其他客戶端的郵件（垃圾郵件除外）。 為什么是這樣？

TCPAccept連接

---

    package game.server;

import java.io.IOException;
import java.net.Socket;

public class TCPAcceptConnections implements Runnable
{
    public static Socket clientSocket = null;;
    int clientID = -1;

    public void run()
    {
        while(Main.TCP)
        {
            try
            {
                clientSocket = TCPServer.serverSocket.accept();
                System.out.println("Client Connected.");
                clientID++;

                new TCPClientManager(clientSocket, clientID).run();
            } 
            catch (IOException e)
            {
                System.out.println("Couldn't create client socket.");
                System.exit(-1);
            }
        }
    }
}

TCPClientManager：

---

    package game.server;

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

public class TCPClientManager implements Runnable
{
    Socket client;

    int clientID;

    static PrintWriter out;
    static BufferedReader in;
    String inputLine, outputLine;

    boolean destroy = false;

    public TCPClientManager(Socket cs, int id)
    {
        try
        {
            client = cs;
            clientID = id;
            out = new PrintWriter(client.getOutputStream(), true);
            in = new BufferedReader(new InputStreamReader(client.getInputStream()));
        } catch(IOException e)
        {
            e.printStackTrace();
        }
    }

    public void run()
    {
        System.out.println("Created TCPManager for client.");
        String command;

        while(!destroy)
        {
            try
            {
                if((command = in.readLine()) != null) //If received something
                {
                    System.out.println("Commad received: " + command);
                        System.out.println(" " + Commands.proccessCommand(command));
                    System.out.println("Command proccessed");
                }
                else
                {
                    client.close();
                    destroy = true;
                }
            } catch (IOException e)
            {
                try
                {
                    client.close();
                } catch (IOException e1)
                {
                    e1.printStackTrace();
                    destroy = true;
                }
                System.out.println("Client lost connection.");
                destroy = true;
            }
        }
        System.out.println("TCPManager for client destroyed.");
    }
}

命令：

---

package game.server;

public class Commands
{
    public static String proccessCommand(String command)
    {
        if(command.equalsIgnoreCase("cp"))
        {
            System.out.println("Creating player...");
                System.out.println("    Retrieved client");
            return "Player Created";
        }
        else
        {
            return "Unkown command: " + command;
        }
    }
}

Answer 1

如果收到未知命令，則應記錄該命令並關閉連接。

但是您有一個更嚴重的問題。 當客戶端處理程序讀取為null時，您不會停止它。 因此，一旦客戶端斷開連接，讀取將永遠無效。 如果readLine（）返回null，則必須關閉套接字並退出循環。 如果收到任何IOException，則還必須關閉套接字。