我正在嘗試制作一個服務器客戶端程序，該程序允許在不等待響應的情況下從服務器向客戶端發(fā)送多條消息，反之亦然。當第一個客戶端連接和斷開連接時，該程序工作正常。但是當我再次連接客戶端時，我得到了錯誤。這是我的服務器代碼：import java.io.DataInputStream;import java.io.DataOutputStream;import java.io.IOException;import java.net.ServerSocket;import java.net.Socket;import java.net.SocketException;import java.io.InputStreamReader;import java.io.BufferedReader;class Q2Server implements Runnable{    private ServerSocket serverSocket;    private Socket socket;    private DataOutputStream out;    private BufferedReader in1;    private DataInputStream in2;    private Thread read, write;    private String clientMsg, serverMsg;    public Q2Server (int port) throws IOException{        serverSocket = new ServerSocket(port);        while(true) {            try {                System.out.println("Waiting for client on port " + serverSocket.getLocalPort() + "...");                socket = serverSocket.accept();                System.out.println("Just connected to " + socket.getRemoteSocketAddress());                out = new DataOutputStream(socket.getOutputStream());                out.writeUTF("Thanks for connecting to " + socket.getLocalSocketAddress());                clientMsg = "";                serverMsg = "";                read = new Thread(this);                write = new Thread(this);                read.start();                write.start();                read.join();                write.join();            } catch(IOException e) {                e.printStackTrace();            } catch(InterruptedException ie) {                ie.printStackTrace();            }        }    }