从服务器读取多行

Question

我对其他方法持开放态度，但这是我的代码：

public class Client {
    public static void main (String [] args) {
        try(Socket socket = new Socket("localhost", 7789)) {
            BufferedReader incoming = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            PrintWriter outgoing = new PrintWriter(socket.getOutputStream(),true);
            StringBuilder sb = new StringBuilder();

            Scanner scanner = new Scanner(System.in);
            String send = "";
            String response = "";

            while (!send.equals("logout")){
                System.out.println("Enter Command: ");
                send = scanner.nextLine();
                outgoing.println(send);
                while ((response = incoming.readLine()) != null) {
                    System.out.println(response);
                    sb.append(response);
                    sb.append('\n');

                    }
            }
        } catch (IOException e) {
            System.out.println("Client Error: "+ e.getMessage());
        }
    }
}

我确实得到了服务器的响应，但是程序卡在了内部 while 循环中while ((response = incoming.readLine()) != null) ，所以我无法输入第二个命令。 如果传入的响应完成，我该如何打破循环？

Answer 1

问题在于，如果套接字关闭，则incoming.readLine()只会返回null ，否则它将阻塞并等待来自服务器的更多输入。

如果您可以更改服务器，您可以添加一些标记，表明请求已被完全处理，然后像这样检查它while ((response = incoming.readLine()) != "--finished--") 。

如果你不能，试试这个：

while(response.isEmpty()){
    if(incoming.ready()){ //check if there is stuff to read
        while ((response = incoming.readLine()) != null){
            System.out.println(response);
            sb.append(response);
            sb.append('\n');
        }
    }
}