努力将字符串从客户端传递到服务器

Question

寻求帮助！我一直试图让这个工作太久了。我最初尝试将服务器和它的 JavaFX 部分（实际阶段、启动方法等）放在同一个 Class 中，但经过数小时的尝试后，我继续将它们分开并从头开始尝试。可惜没有运气。

这是我的服务器：

public class Server
{
    String s = "";
   public void startServer() throws UnknownHostException, IOException
    {
        ServerSocket server = new ServerSocket (8896);
        while(true)
        {
                    Socket socket = null;
                    try
                    {
                            socket = server.accept();
                            System.out.println("Connected");
                            BufferedReader dis = new BufferedReader(new InputStreamReader(socket.getInputStream()));
                            s = dis.readLine();
                            System.out.println(dis.readLine());
                    }
                    catch(IOException e){}
                    finally
                    {
                        if(socket != null)
                            try
                            {
                                    socket.close();
                            }
                            catch(IOException e){}
                    }
            }
    }
    public  String giveString()
    {
        return s;
    }
}

我的客户：

public class Client
{
    private String string = "";
    private Socket s;

    public void connect() throws UnknownHostException, IOException
    {
        s = new Socket("localhost",8896);
        PrintStream dos = new PrintStream(s.getOutputStream(),true);
        dos.println(string);
        dos.flush();
        s.close();   
    }

    public void setString(String string)
    {
        this.string = string;
    }
}

最后，我的 ServerGUI class。我想在我添加到场景的 TextField 中显示通过 Client->Server.giveString()->ServerGUI 传递的字符串 s。

public class ServerGUI extends Application
{
    private TextField tf = new TextField("");
    private static Server server = new Server();
    private SimpleStringProperty ssp = new SimpleStringProperty();

    public void initialize() throws UnknownHostException, IOException
    {


        ssp.bind(tf.textProperty());
        tf.textProperty().set(server.giveString());
        ssp.setValue(server.giveString());
        server.startServer();
    }

    public void start(Stage primaryStage) throws UnknownHostException, IOException
    {
        VBox root = new VBox();
        Scene scene = new Scene(root, 380, 200);
        root.getChildren().add(tf);
        primaryStage.setScene(scene);
        primaryStage.show();
        server.startServer();
    }

    public static void main(String[] args) throws UnknownHostException, IOException
    {

        launch(args);
    }

}

我试着把 server.startServer();已经在 ServerGUI 中的不同位置，结果不同。从未找到解决方案。我确信这很简单，如果有人能给我一些指示，我将不胜感激。我根本没有取得任何进展，我觉得我尝试了这里的每一个想法。

Answer 1

您的代码存在问题，您的服务器 class 调用了 accept()。等待客户端套接字启动。您的代码永远不会通过这一点，因为线程只是在那里等待。您可以查看我在下面发布的代码，看看这是真的。我在创建客户端的线程中有一个 Thread.sleep(6000)（6 秒），因此您可以看到服务器在接受 Socket 之前永远不会打印出 "Connected"。

import javafx.application.Application;
import javafx.application.Platform;
import javafx.beans.property.SimpleStringProperty;
import javafx.scene.Scene;
import javafx.scene.control.Label;
import javafx.scene.layout.VBox;
import javafx.stage.Stage;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.UnknownHostException;

public class Test extends Application
{
    private Label tf = new Label("");
    private static Server server = new Server();

    @Override
    public void start(Stage primaryStage)
    {
        VBox root = new VBox();
        Scene scene = new Scene(root, 380, 200);
        root.getChildren().add(tf);
        primaryStage.setScene(scene);
        primaryStage.show();

        tf.textProperty().bind(server.passedStringValProperty());

        new Thread(() -> {
            try {
                server.startServer();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }, "Server socket listener").start();

        new Thread(() -> {
            try {
                Thread.sleep(6000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
            Client client = new Client();
            client.setString("Hello world!");
            try{
                client.connect();
            } catch (IOException e) {
                e.printStackTrace();
            }


        }, "Client connection").start();
    }

    public static void main(String[] args) throws UnknownHostException, IOException
    {
        launch(args);
    }

    private static class Server
    {

        public SimpleStringProperty passedStringValProperty () {
            return passedStringVal;
        }

        private SimpleStringProperty passedStringVal = new SimpleStringProperty();

        public void startServer () throws UnknownHostException, IOException {
            ServerSocket server = new ServerSocket(8896);

            // Removed while loop since you only need 1 instance
            Socket socket = null;
            try {
                socket = server.accept();
                System.out.println("Connected");
                BufferedReader dis = new BufferedReader(new InputStreamReader(socket.getInputStream()));
                final String passedVal = dis.readLine();

                Platform.runLater(() -> {
                            passedStringVal.set(passedVal);
                        });

                System.out.println(passedVal);
            } catch (IOException ignored) {
            } finally {
                if (socket != null)
                    try {
                        socket.close();
                    } catch (IOException ignored) {
                    }
            }
        }
    }

    private static class Client{
        private String string = "";
        private Socket s;

        public void connect() throws IOException
        {
            s = new Socket("localhost",8896);
            PrintStream stream = new PrintStream(s.getOutputStream(),true);
            stream.println(string);
            s.close();
        }

        public void setString(String string)
        {
            this.string = string;
        }
    }
}

您可以将 Client 和 Server 分成它们自己的 classes，我只是将它们保留为静态 classes 以便将它们放入主 class。我还从您的代码中删除了 while(true) 循环。仅当您想要继续检查套接字时才需要循环。服务器 class 中的代码也将挂在 readLine() 直到客户端发送一些东西（您可以通过在 stream.println() 之前在客户端的连接函数中放置一个 Thread.sleep() 调用来测试它.

所以你无法通过 server.startServer() 的原因是因为它在主线程中运行并挂起所有内容。

努力将字符串从客户端传递到服务器

Struggling with passing String from Client to Server

client

javafx

stream

server