cmd中的Java套接字编程

Question

So I have the following code that runs on the telnet login in linux. How to make this run in cmd? I tried running the tcp client and server programs in cmd but I am not getting the output. Here is my code that runs on linux telnet but not on windows cmd.

import java.io.*;
import java.net.*;
class tcpclient{
public static void main(String args[])throws Exception{
    String hwaddr,modsentence;
    BufferedReader inFromUser=new BufferedReader(new      InputStreamReader(System.in));
    Socket clientSocket=new Socket("localhost",2057);
    DataOutputStream outToServer= new DataOutputStream(clientSocket.getOutputStream());
    BufferedReader inFromServer=new BufferedReader(new    InputStreamReader(clientSocket.getInputStream())); 
    System.out.print("Enter Ip address");
    hwaddr=inFromUser.readLine();
    outToServer.writeBytes(hwaddr+""+"\n");
    modsentence=inFromServer.readLine();
    System.out.println("FROM SERVER:"+modsentence);
    clientSocket.close();
}
}
import java.net.*;
import java.io.*;
class tcpserver{
    public static void main(String args[])throws Exception
    {
        String clientSentence;
        ServerSocket welcomeSocket = new ServerSocket(2057);
        while(true)
        {
            Socket connectionSocket=welcomeSocket.accept();
            BufferedReader inFromClient=new BufferedReader(new InputStreamReader(connectionSocket.getInputStream()));
            DataOutputStream outToClient=new DataOutputStream(connectionSocket.getOutputStream());
            clientSentence=inFromClient.readLine();
            if(clientSentence.equals("a"))
                outToClient.writeBytes("testtt");

       }
   }
}

Answer 1

To answer the question: It's not relevant whether you use bash or CMD. Socket programming is the same because the shell doesn't interfere. You send some characters to the server and the servers sends some characters back. I have tested this in CMD and it works the same.

Answer 2

Change

outToClient.writeBytes("testtt");

to

outToClient.writeBytes("testtt\n");

According to https://docs.oracle.com/javase/7/docs/api/java/io/BufferedReader.html#readLine()

readLine() Reads a line of text. A line is considered to be terminated by any one of a line feed ('\\n') , a carriage return ('\\r'), or a carriage return followed immediately by a linefeed.

This would make

modsentence = inFromServer.readLine();

return a String and assign it to modsentence.

Also remember that your tcpserver only responds to character "a".

Answer 3

If you use a BufferedReader then you should also use a BufferedWriter . Also note DataInputStream.readLine() is deprecated and should not be used. With all that being said, yes there is a difference between the Command Prompt in Windows, and the Shell in Linux. Windows uses \\r\\n as a line terminator, and Linux uses \\n . If you use \\r\\n as a line feed, it should work fine on all platforms. However you never will realistically use the Command Prompt in a real client/server architecture so it's best not to base your application off of windows ancient features. use \\n .

Try using Scanner to get input from System.in