Java套接字TCP发送和接收

Question

I tried many examples and none worked as I expect. What do I need?

1. Send a packet through an IP and Port.
2. Wait until server response and close socket.

Example:

[Client] Send: "Hi server"
[Client] Wait
[Server] Send: "Hi client"
[Client] Receive response
[Client] Close socket

I just need TCP client, server side is solved.

Tried: http://www.careerbless.com/samplecodes/java/beginners/socket/SocketBasic1.php

My code

public class SendPacket {

    public void send() throws Exception{

        Socket socket = null;
        ObjectOutputStream oos = null;
        ObjectInputStream ois = null;

        socket = new Socket(ip, port);
        oos = new ObjectOutputStream(socket.getOutputStream());

        String msg = "DSPSYSSTS";
        oos.write(msg.getBytes());
        oos.flush();

        //read the server response message
        ois = new ObjectInputStream(socket.getInputStream());
        String message = (String) ois.readObject();

        RunWinCmd runCmd = new RunWinCmd();
        runCmd.run("notepad.exe \"" + message + "\"");
        //close resources
        ois.close();
        oos.close();

    }
}

Answer 1

you have to initialise the streams in a particular order.

try this (not tested):

public class SendPacket {

    public void send() throws Exception{

        Socket socket = null;
        ObjectOutputStream oos = null;
        ObjectInputStream ois = null;

        socket = new Socket(ip, port);
        oos = new ObjectOutputStream(socket.getOutputStream());
        ois = new ObjectInputStream(socket.getInputStream());

        String msg = "DSPSYSSTS";
        oos.write(msg.getBytes());
        oos.flush();

        //read the server response message
        String message = (String) ois.readObject();

        RunWinCmd runCmd = new RunWinCmd();
        runCmd.run("notepad.exe \"" + message + "\"");
        //close resources
        ois.close();
        oos.close();
        socket.close();//!!!!

    } }