Java Socket Server與Python客戶端的通信，程序不會進入“ inputLine = in.readLine（）”循環

Question

我正在嘗試用Java創建可以與python客戶端通信的套接字服務器。 我遇到了一個問題，如果我啟動服務器，通過python發送一條消息，然后立即退出，那么一切運行正常，但是如果客戶端發送一條消息，然后再次監聽套接字，服務器將不會響應。

這是代碼，主要來自oracle的此示例

public class PrimeServer {

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

        int portNumber = 4444;

        try (
                ServerSocket serverSocket = new ServerSocket(portNumber);
                Socket clientSocket = serverSocket.accept();
                PrintWriter out =
                        new PrintWriter(clientSocket.getOutputStream(), true);
                BufferedReader in = new BufferedReader(
                        new InputStreamReader(clientSocket.getInputStream()))
        ) {

            String inputLine;
            String outputLine;
            String rawMessage;

            // Initiate conversation with client
            PrimeProtocol ppc = new PrimeProtocol();
            outputLine = String.format("%1022s", "Ready").replace(' ', '0');
            out.println(outputLine);
            System.out.println("Over while");
            while ((inputLine = in.readLine()) != null) {
                System.out.println("In while");
                if (ppc.processInput(Integer.parseInt(inputLine))){
                    rawMessage = "True";
                } else {
                    rawMessage = "False";
                }
                outputLine = String.format("%1024s", rawMessage).replace(' ', '0');
                System.out.println("Outputting " + rawMessage);
                out.println(outputLine);

            }
            System.out.println("Passed while.");
        } catch (IOException e) {
            System.out.println("Exception caught when trying to listen on port "
                    + portNumber + " or listening for a connection");
            System.out.println(e.getMessage());
        }
    }
}

和python代碼很好的衡量：

msg_len = 1024
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect(("127.0.0.1", 4444))
init_message = sock.recv(msg_len).decode("UTF-8")
init_message = init_message.replace('0', '')
print(init_message)
print(len(init_message))
sock.send(b'3')

使用此代碼，java服務器的輸出為：

Over while
In while
Outputting True
Passed while.

客戶端輸出為：

1024
Ready

之后，連接斷開。

但是，如果我將此行添加到客戶端： new_message = sock.recv(msg_len).decode("UTF-8")制作新的python：

msg_len = 1024
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect(("127.0.0.1", 4444))
init_message = sock.recv(msg_len).decode("UTF-8")
print(len(init_message))
init_message = init_message.replace('0', '')
print(init_message)

sock.send(b'3')

new_message = sock.recv(msg_len).decode("UTF-8")

服務器阻塞，輸出僅為：

Over while

當客戶端輸出：

1024
Ready

同時也干擾。

有什么想法嗎？

Answer 1

原來是需要刷新的python套接字。 新的python代碼：

msg_len = 1024
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect(("127.0.0.1", 4444))
init_message = sock.recv(msg_len).decode("UTF-8")
print(len(init_message))
init_message = init_message.replace('0', '')
print(init_message)

sock.send(b'3\n')

new_message = sock.recv(msg_len).decode("UTF-8")
print(new_message)

（在\\ n后面添加了）。