我正在用 java 设置一个简单的 TCP 客户端服务器交互。
服务器:
服务器是用 Java 编写的桌面客户端:
import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;
class TCPServer
{
public static int PORT_NUMBER = 6129;
public static void main(String argv[]) throws Exception
{
String clientMessage;
ServerSocket welcomeSocket = new ServerSocket(PORT_NUMBER);
while (true)
{
Socket connectionSocket = welcomeSocket.accept();
BufferedReader inFromClient = new BufferedReader(new InputStreamReader(connectionSocket.getInputStream()));
DataOutputStream outToClient = new DataOutputStream(connectionSocket.getOutputStream());
clientMessage = inFromClient.readLine();
System.out.println("Received: " + clientMessage);
outToClient.writeBytes("I received this: "+ clientMessage +"\n");
}
}
}
客户:
客户端是一个通过 TCP 连接到服务器的 android 应用程序。在客户端中,我有一个方法 sendMessage(String msg)
尝试向服务器发送消息。
public static void sendMessage(String msg) throws IOException
{
if (mainSocket == null)
{
return;
}
if (!mainSocket.isConnected())
{
connectSocket();
}
PrintWriter output = new PrintWriter( mainSocket.getOutputStream());
output.println(msg);
output.flush();
System.out.println(msg);
}
问题是,服务器接收到第一条消息,但任何后续消息都不会显示。当我关闭客户端时,所有其他消息突然同时出现在服务器中。
这是服务器看到的:
Received: message 1
长时间没有 Activity ...
然后我关闭客户端
Received: message 2 message 3 message 4 message 5 etc..
我在 sendMessage() 方法中放置了一个 println,该方法本身是实时调用的。
最佳答案
每次发送消息时,您都需要在客户端显式close()
您的PrintWriter
。当您完成读取 inFromClient
时,服务器端也是如此,当您完成写入 outToClient
时,同样如此。
另见 basic example , 他们很好地解释了基本的工作流程:
However, the basics are much the same as they are in this program:
Open a socket.
Open an input stream and output stream to the socket.
Read from and write to the stream according to the server's protocol.
Close the streams.
Close the socket.
关于java - TCP 客户端/服务器通信只发送第一条消息?,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/7154071/