Java 服务器客户端通信似乎卡住了

Question

你好 Whosebug 社区，

我在 Java 中遇到有关套接字通信的问题。

这是我的服务器和客户端的示例代码class:

服务器：

public class OTPServer {


static ServerSocket serverSocket;
final static int PORT = 4242;
static Socket clientConnection;

public static void main(String[] args) {

    try {
        serverSocket = new ServerSocket(PORT);
        System.out.println("Socket initialized");
        String serverMessage = "Hello, I am the Host";
        ServerTool serverTool = new ServerTool();

        while (true) {
            clientConnection = serverSocket.accept();
            if(clientConnection.isConnected()) {
                System.out.println("Client connected");
            }

            BufferedReader clientInputReader = new BufferedReader(new InputStreamReader(clientConnection.getInputStream()));
            DataOutputStream serverOutput = new DataOutputStream(clientConnection.getOutputStream());
            System.out.println("Sending message to client: " + serverMessage);
            serverOutput.writeBytes(serverTool.encodeMessage(serverMessage));
            serverOutput.flush();
            String clientMessage = clientInputReader.readLine();
            System.out.println("Encoded answer from client: " + clientMessage);
            String decodedMessage = serverTool.decodeMessage(clientMessage);
            System.out.println("Decoded answer from client: " + decodedMessage);

            serverOutput.close();
            clientInputReader.close();

        }
    } catch (IOException e) {
        e.printStackTrace();
    }
    System.out.println("Hello, I am the OTP Server!");

}

这是客户：

public class OTPClient {

static Socket clientSocket;
final static int PORT = 4242;
final static String HOST = "localhost";


public static void main(String[] args) {
    System.out.println("I am the OTP Client!");
    String serverMessage;
    String clientResponse = "I am the Client";
    OTPTool otpTool = new OTPTool();

    try {

        clientSocket = new Socket(HOST, PORT);
        BufferedReader serverInput = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
        DataOutputStream outputStream = new DataOutputStream(clientSocket.getOutputStream());
        System.out.println("Connection to Host established");
        serverMessage = serverInput.readLine();
        System.out.println("Encoded Message from Server: " + serverMessage);
        String decodedMessage = otpTool.decodeMessage(serverMessage);
        System.out.println("Decoded message from Server: " + decodedMessage);
        System.out.println("Answering with own message: " + clientResponse);
        outputStream.writeBytes(clientResponse);
        outputStream.flush();
        outputStream.close();
    } catch (IOException e) {
        e.printStackTrace();
    }

}

现在我的问题在哪里：

连接建立，服务器似乎向客户端发送消息并等待答复。客户端不打印他从服务器获得的消息。一旦我取消服务器，客户端就会打印它从服务器获得的消息以及信息，答案是发送端退出，退出代码为 0，所以看起来这部分很好，只是不知何故卡住了。正如您在给出的示例代码中看到的那样，我已经尝试刷新 outputStream。

我是否遗漏了一些明显的东西？我知道，这是非常基本的东西，但这是我第一次使用套接字进行通信。

提前致谢！

此致，罗尼

顺便说一句：我知道服务器只连接到一个请求连接的客户端。完全够我用了。

Answer 1

它卡住了，因为 serverInput.readLine(); 阻塞，直到遇到换行符或文件结尾。在服务器端，您没有发送换行符，因此客户端会阻塞。

Java 服务器客户端通信似乎卡住了

Java Server Client communication seems to stuck

java

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client-server

communication