java - TCP Server 只接收一条消息

Question

我正在尝试创建一个简单的 TCP 服务器和客户端。我希望客户端能够通过只打开一次套接字来发送多条消息。我看过类似的问题here , here , 和 here但它们并没有多大用处。

我的代码如下:

SampleServerTCP.java

public class SampleServerTCP {
    private static final int DEFAULT_PORT_NUMBER = 39277;

    public static void main(String[] args) throws IOException {
        ServerSocket defaultSocket = new ServerSocket(DEFAULT_PORT_NUMBER);

        System.out.println("Listening on port: " + DEFAULT_PORT_NUMBER);
        while (true){
            Socket connectionSocket = defaultSocket.accept();
            BufferedReader fromClient= new BufferedReader(new     InputStreamReader(connectionSocket.getInputStream()));
            String msg = fromClient.readLine();
            System.out.println("Recieved: " + msg);
        }
    }
}

TCPClientTest.java

public class TCPClientTest {

    public static void main(String args[]) throws UnknownHostException, IOException, InterruptedException{
        Socket clientSocket = new Socket("localhost", 39277); 
        DataOutputStream outToServer = new DataOutputStream(clientSocket.getOutputStream());

        int c = 0;
        while(c<10){
            outToServer.writeBytes(c + "\n");
            outToServer.flush();
            c++;
            Thread.sleep(500);
        }
        clientSocket.close();
    }
}

我得到的唯一输出是:

Listening on port: 39277
Recieved: 0

我哪里错了？

Answer 1

你的问题出在这里:

ServerSocket defaultSocket = new ServerSocket(DEFAULT_PORT_NUMBER);

    System.out.println("Listening on port: " + DEFAULT_PORT_NUMBER);
    while (true){
        Socket connectionSocket = defaultSocket.accept();
        BufferedReader fromClient= new BufferedReader(new     InputStreamReader(connectionSocket.getInputStream()));
        String msg = fromClient.readLine();
        System.out.println("Recieved: " + msg);
    }

您正在打开套接字，只读取一行，然后等待下一个套接字。

相反，您应该在 while 循环之外执行 Socket connectionSocket = defaultSocket.accept();，并在循环中从该套接字读取数据，如下所示:

System.out.println("Listening on port: " + DEFAULT_PORT_NUMBER);
Socket connectionSocket = defaultSocket.accept();
BufferedReader fromClient= new BufferedReader(new     InputStreamReader(connectionSocket.getInputStream()));
String msg = "";
while ((msg = fromClient.readLine()) != null){    
    System.out.println("Recieved: " + msg);
}