java - java中的套接字服务器

Question

我使用 Socket 在 java 中进行了简单的客户端/服务器聊天。问题是程序相互连接，但由于某些原因我无法从双方获取/接收数据。当我断开服务器连接时，客户端给我一个错误“连接重置”，这表明它们已连接，但不交换数据。

代码与 Java 教程中的代码相同，取自 here .

/*
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 * and open the template in the editor.
 */
package javaapplication3;

/**
 *
 * @author Amr
 */
import java.net.*;
import java.io.*;

public class KnockKnockServer {
    public static void main(String[] args) throws IOException {

        ServerSocket serverSocket = null;
        try {
            serverSocket = new ServerSocket(4440);
        } catch (IOException e) {
            System.err.println("Could not listen on port: 4444.");
            System.exit(1);
        }

        Socket clientSocket = null;
        try {
            clientSocket = serverSocket.accept();
            System.out.println(Inet4Address.getLocalHost());
        } catch (IOException e) {
            System.err.println("Accept failed.");
            System.exit(1);
        }

        PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);
        BufferedReader in = new BufferedReader(
                new InputStreamReader(
                clientSocket.getInputStream()));
        String inputLine, outputLine;


        while ((inputLine = in.readLine()) != null) {
             outputLine = "heelo";
             out.println(outputLine);
             if (outputLine.equals("Bye."))
                break;
        }
        out.close();
        in.close();
        clientSocket.close();
        serverSocket.close();
    }
}

import java.io.*;
import java.net.*;

public class KnockKnockClient {
    public static void main(String[] args) throws IOException {

        Socket kkSocket = null;
        PrintWriter out = null;
        BufferedReader in = null;

        try {
            kkSocket = new Socket(Inet4Address.getLocalHost(), 4440);
            out = new PrintWriter(kkSocket.getOutputStream(), true);
            in = new BufferedReader(new InputStreamReader(kkSocket.getInputStream()));
        } catch (UnknownHostException e) {
            System.err.println("Don't know about host: taranis.");
            System.exit(1);
        } catch (IOException e) {
            System.err.println("Couldn't get I/O for the connection to: taranis.");
            System.exit(1);
        }

        BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in));
        String fromServer;
        String fromUser;

        while ((fromServer = in.readLine()) != null) {
            System.out.println("Server: " + fromServer);
            if (fromServer.equals("Bye."))
                break;

            fromUser = stdIn.readLine();
        if (fromUser != null) {
                System.out.println("Client: " + fromUser);
                out.println(fromUser);
        }
        }

        out.close();
        in.close();
        stdIn.close();
        kkSocket.close();
    }
}

Answer 1

建立连接后，服务器所做的第一件事是

while ((inputLine = in.readLine()) != null)

也就是说，它等待客户端说些什么。

您的客户做的第一件事是

while ((fromServer = in.readLine()) != null)

也就是说，它等待服务器说些什么。

让两者之一先发送一些东西，它应该可以工作。