java - 无法从套接字读取

Question

我已经设置了一个 pi 零，在我的本地网络上运行一个简单的 python 服务器脚本来响应某些命令。我正在尝试从 android java 应用程序发送这些命令。但是当我尝试读取我发送的命令的回复时，它似乎跳过了该行。因为“D/正在发送数据:数据已发送”是最后打印到日志中的内容。

这是我用来发送命令然后打印服务器回复的嵌套可运行类:

private class SendData implements Runnable
    {
        private byte[] dataToSend;
        private Socket socket;
        private OutputStream outputStream;

        private BufferedReader bufferedReader;

        public SendData(Socket socket, byte[] dataToSend)
        {
            this.socket = socket;
            this.dataToSend = dataToSend;
        }

        @Override
        public void run()
        {
            try
            {
                outputStream = socket.getOutputStream();
                outputStream.write(dataToSend);
                Log.d("Sending data", "Data has been send");
                bufferedReader = new BufferedReader(new InputStreamReader(socket.getInputStream()));

                Log.d("Received", bufferedReader.readLine());

            }
            catch (IOException e)
            {
                Log.e("IOException Sending data", e.getMessage());
            }
        }
    }

但是当我尝试从 bufferedreader 中读取时，应用程序就会退出。虽然服务器确实发送了回复。

线程从此方法开始，其中“data”是一个字符串。

if (socket != null)
        {
            Thread sendThread = new Thread(new SendData(socket, data.getBytes()));
            Log.d("SocketClient send", "Starting send thread");
            sendThread.start();
            try
            {
                sendThread.join();
            }
            catch (InterruptedException e)
            {
                Log.d("SocketClient constructor", "Could not join");
            }
        }
        else
        {
            Log.d("SocketClient send", "Socket is null");
        }

在 pi 上运行的 Python 脚本:

import socket
import sys
from datetime import datetime

host = "192.168.4.1"
port = 12345

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)

sock.bind((host, port))

sock.listen(1)

def data_client(conn, ipStr):
    while True:
        data = conn.recv(2048)
        reply = handle_command(data)
        print "Command: %s" % data
        if not data or data == "con_close":
            print "Connection %s closed" % ipStr
            break
        conn.send(reply)
        print "Send: %s" % reply
    conn.close()

def handle_command(cmd):
    if (cmd == "con_close"):
        return cmd
    elif (cmd == "get_time"):
        return str(datetime.now())
    else:
        return "err_invalid_command"

while True:
    print "listening:"
    conn, addr = sock.accept()
    print "Got connection from %s" % addr[0]
    data_client(conn, addr[0])

Answer 1

如果接收方尝试读取一行，则发送方应该发送一行。

接收方尝试使用 readLine() 读取一行，但 readLine() 永远不会返回，因为它等待尚未发送的换行符。