Java服务器/客户端应用程序仅在按Enter键时显示消息

Question

Server Side:

try {
    ServerSocket server_socket=new ServerSocket(port_number);
    Socket client_socket= server_socket.accept();
    PrintWriter output = new PrintWriter(client_socket.getOutputStream(),true);
    BufferedReader input = new BufferedReader(new InputStreamReader(client_socket.getInputStream()));
    BufferedReader stdIn=new BufferedReader(new InputStreamReader(System.in));
    String userInput, clientOutput;
    while ((userInput=stdIn.readLine())!="EXIT") {
        if ((clientOutput=input.readLine())!=null) {
            System.out.println("Client: "+clientOutput);
        } if (userInput!=null) {
            output.println(userInput);
            output.flush();
        }
    }
}

Client Side:

try {
    Socket client_socket= new Socket(hostname,port_number);
    PrintWriter output = new PrintWriter(client_socket.getOutputStream(),true);
    BufferedReader input = new BufferedReader(new InputStreamReader(client_socket.getInputStream()));
    BufferedReader stdIn=new BufferedReader(new InputStreamReader(System.in));

    String userInput,serverOutput;
    while ((userInput=stdIn.readLine())!="EXIT") {
        if ((serverOutput=input.readLine())!=null) {
            System.out.println("Server: "+serverOutput);
        } if (userInput!=null) {
            output.println(userInput);
            output.flush();
        }
    }
}

The code in my case makes sense to me, I cant seem to figure out why an enter still needs to be pressed, does it have something to do with .readLine() ? I checked out the following post Server Client in Java only displays message when I press enter , however the solution provided does not fix the situation.

Note: Initially there were no if statements in the while loop. The way I saw this to be an issue was that the while loop may get stuck on one of the lines, waiting for user/server input. Therefore implementing if statements allowed it to skip the waiting portion and re-run the loop.

Answer 1

Turns out I mixed my variables up. The while loops should be:

 while ((userInput=input.readLine())!="EXIT") {

It fixed it, but there are some other issues still present

Answer 2

does it have something to do with .getLine()?

Yes. If you look at the Javadoc for BufferedReader#readLine() , it clearly states that an end of line character terminates the String to be read:

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.