Java 双向套接字连接答案

【问题标题】：Java Two-Way Socket ConnectionJava 双向套接字连接
【发布时间】：2022-02-02 02:11:48
【问题描述】：

我正在努力在 Java 中创建客户端和服务器之间的基本双向套接字连接。按照我在网上其他地方找到的一些指南，我让它以一种方式工作，服务器从客户端接收消息，但我很好奇我将如何制作它，以便客户端和服务器可以相互发送消息。我也在努力实现一个有效负载，但直到我设法让双向连接正常工作之后，我才担心这一点。

这是我的服务器代码：

import java.net.*;
import java.io.*;
public class ServerDemo {
    private Socket mySocket = null;
    private ServerSocket server = null;
    private DataInputStream input = null;
    
    public ServerDemo(int port)
    {
         try
         {
               server = new ServerSocket(port);
               System.out.println("Server started");
               System.out.println("Waiting for a client ...");
               mySocket = server.accept();
               System.out.println("Client accepted");
               input = new DataInputStream(
                        new BufferedInputStream(mySocket.getInputStream()));
               String newLine = "";
               while (!newLine.equals("Over"))
               {
                    try
                    {
                        newLine = input.readUTF();
                        System.out.println(newLine);
                    }
                    catch(IOException i)
                    {
                        System.out.println(i);
                    }
               }
               System.out.println("Closing connection");
               mySocket.close();
               input.close();
         }
         catch(IOException i)
         {
              System.out.println(i);
         }
    }
 
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        ServerDemo server = new ServerDemo(5000);
    }

}

这是客户端的代码：

import java.net.*;
import java.util.Scanner;
import java.io.*;
public class ClientDemo {
    private Socket mySocket = null;
    private BufferedReader input= null;
    private DataOutputStream output = null;

    public ClientDemo(String address, int port)
    {
        try
        {
            mySocket = new Socket(address, port);
            System.out.println("Connected");
            input = new BufferedReader(new InputStreamReader(System.in));
            output = new DataOutputStream(mySocket.getOutputStream());
        }
        catch(UnknownHostException u)
        {
            System.out.println(u);
        }
        catch(IOException i)
        {
            System.out.println(i);
        }
        String newLine = "";
        while (!newLine.equals("Over"))
        {
            try
            {
                newLine = input.readLine();
                output.writeUTF(newLine);
            }
            catch(IOException i)
            {
                System.out.println(i);
            }
        }
        try
        {
            input.close();
            output.close();
            mySocket.close();
        }
        catch(IOException i)
        {
            System.out.println(i);
        }
    }

    public static void main(String[] args) {
        String response="";
        Scanner myScanner = new Scanner(System.in);
        System.out.println("Please enter a server to connect to.");
        response=myScanner.next();
        ClientDemo client = new ClientDemo(response, 5000);
    }
}

对于如何将其转换为双向通信的任何建议，我将不胜感激。

【问题讨论】：

标签： java sockets server network-programming client

【解决方案1】：

为了让服务器将消息发送回客户端，您必须使用mySocket.getOutputStream()从服务器（ServerDemo）响应客户端

有多种方法，

使用 OutputStreamWriter

BufferedWriter buffer = new BufferedWriter(new OutputStreamWriter(mySocket.getOutputStream(), "UTF8"));
buffer.append(stringToSend).append("\n");
buffer.append("Over").append("\n");
buffer.flush();

使用 PrintWriter

PrintWriter out = new PrintWriter(mySocket.getOutputStream());
String response = "Data received successfully";
out.print(response);

为了打印来自服务器的响应，可以在 ClientDemo try/catch 块中使用以下代码 sn-p关闭。

BufferedReader bufferIn=new BufferedReader(new InputStreamReader(mySocket.getInputStream()));
String message;
while(!(message = bufferIn.readLine()).equals("Over")){
    System.out.println(message);
}

【讨论】：