Question

因此，作为我的项目，我必须编写一个客户端类和一个简单的服务器类，它将由客户端编写ECHO消息。

出于某种原因，我要么得到I / O异常，要么关闭套接字的异常循环。

我真的很感激一些帮助，因为我连续两天都在努力解决这个问题而无法找到任何解决方案。

我的服务器类：

import java.io.*;
import java.net.*;
import java.util.regex.Pattern;

public class SimpleServer {
    private ServerSocket ss = null;
    private BufferedReader in = null;
    private PrintWriter out = null;

public SimpleServer(String host, int port) {
    try {
    InetSocketAddress isa = new InetSocketAddress(host, port);
    ss = new ServerSocket();
    ss.bind(isa);
    } catch (IOException exc) {
        System.out.println("Error in constructor");
        System.exit(1);
    }
    System.out.println("Server started.");
    System.out.println("on port: " + ss.getLocalPort());
    System.out.println("bind address: " + ss.getInetAddress());
    serviceConnections();       
}//constructor

private void serviceConnections() {     
    boolean serverRunning = true;

    while(serverRunning) {
        try {
            Socket conn = ss.accept();
            System.out.println("Connection established!");
            serviceRequests(conn);              
        } catch (Exception exc) {
            exc.printStackTrace();
        }

        try { ss.close(); } catch (Exception exc) {}
    }       
}//serviceConnections

private void serviceRequests(Socket connection) throws IOException {
    try {
        in = new BufferedReader(new      InputStreamReader(connection.getInputStream()));
        out = new PrintWriter(connection.getOutputStream(), true);
        String line = in.readLine();            
        out.println(line);
    } catch (Exception exc) {
        exc.printStackTrace();
    } finally {
        try {
            in.close();
            out.close();
            connection.close();
            connection = null;
        } catch(Exception exc) {}
    }
}//serviceReq       

public static void main(String[] args) {

    String host = "localhost";
    int port = 2401;            
    new SimpleServer(host,port);        
}//main 
}//class

我的客户端类：

import java.net.*;
import java.io.*;


public class SimpleServerClient {

    private Socket sock = null;
    private PrintWriter out = null;
    private BufferedReader in = null;

public SimpleServerClient (String host, int port) {     
    try {
        sock = new Socket(host, port);
        out = new PrintWriter(sock.getOutputStream(),true);
        in = new BufferedReader(new InputStreamReader(sock.getInputStream()));
    //  System.out.println("Connected to the: " + sock.getInetAddress() );
        makeRequest("ECHO Howdy boy");      


    } catch (UnknownHostException e) {
        System.err.println("Unknown host: "+host);
        System.exit(2);
    } catch (IOException e) {
        System.err.println("I/O error for");
        System.exit(3);
    } catch (Exception exc) {
        exc.printStackTrace();
        System.exit(4);
    }
}//constructor

private void makeRequest(String req) throws IOException {
    System.out.println("Request: " + req);
    out.println(req);
    String resp = in.readLine();
    System.out.println(resp);
    disconnect();
}//method

public void disconnect() {
    try {
    out.close();
    sock.close();
    in.close();     
    } catch(IOException exc) {
        System.out.println("Error while closing");
        System.exit(5);
    }
}//method

public static void main(String[] args) {
    new SimpleServerClient("localhost", 2401);
}//main
}//class

Answer 1

它（应该）的工作方式：

服务器打开ServerSocket并接受ServerSocket上的连接每个连接（新客户端）[应在单独的线程中处理]是与其自己的I / O通道的单独的新Socket连接。对于每个新的Socket，您应该打开一次I / O通道并保持打开状态，直到客户端断开连接。

如果遵循这个逻辑，一切都会奏效。

Answer 2

我已经分享了一个很好的聊天程序，其中有一台服务器使用TCP协议与多个客户端进行通信。

请查看Java Server with Multiclient communication.

它可能对你有所帮助。与此同时，我正在寻找你的代码。

在您的代码中，您在与单个客户端连接后关闭了套接字。

以下是修复：

private void serviceConnections() {
    boolean serverRunning = true;

    while (serverRunning) {
        try {
            Socket conn = ss.accept();
            System.out.println("Connection established!");
            serviceRequests(conn);
        } catch (Exception exc) {
            exc.printStackTrace();
        }

    }
    try {
        ss.close();
    } catch (Exception exc) {
    }
}// serviceConnections

基本的echo服务器，客户端 - 服务器关系

2 个答案: