修改

Question

我编写了一个程序，客户端应该能够建立连接，并将som消息写入服务器。服务器应该打印此消息。

问题是，一旦客户端连接到服务器，我就会收到以下消息的异常：

java.net.ConnectException: connect: Address is invalid on local machine, or port is not valid on remote machine
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:351)
at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:213)
at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:200)
at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
at java.net.Socket.connect(Socket.java:529)
at java.net.Socket.connect(Socket.java:478)
at java.net.Socket.<init>(Socket.java:375)
at java.net.Socket.<init>(Socket.java:189)
at Client.<init>(Client.java:21)
at Server.startServer(Server.java:42)
at Server.main(Server.java:62)

我的服务器代码如下所示：

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

public class Server {

    private int port = 5555;

    public void printServerAddress() {
        InetAddress i = null;
        String host = null;

        try {
            i = InetAddress.getLocalHost();

        } catch (UnknownHostException e) {
            e.printStackTrace();
        }

        host = i.getHostAddress();

        System.out.println("Contact this server at address: " + host + " and port: " + port);
    }

    public void startServer() {
        ServerSocket serverSocket = null;
        BufferedReader reader = null;
        Socket socket = null;
        String fromClient = null;

        try {

            serverSocket = new ServerSocket(port);

            while(true) {
                socket = serverSocket.accept();
                reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));

                if(socket != null) {
                    System.out.println("Connection from: " + socket);
                }

                Thread thread = new Thread(new Client(socket));
                thread.start();

                while((fromClient = reader.readLine()) != null) {
                    System.out.println("From client: " + fromClient);
                }

                reader.close();
                socket.close();
            }

        } catch (IOException e) {

        }
    }

    public static void main(String[] args) {
        Server server = new Server();
        server.printServerAddress();

        server.startServer();
    }

}

客户端的代码是：

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.Scanner;


public class Client implements Runnable{

    private int port;
    private String serverAddress;
    private PrintWriter writer;
    private BufferedReader reader; 

    public Client(Socket socket)
    {
        try {

            socket = new Socket(serverAddress, port);
            writer = new PrintWriter(socket.getOutputStream(), true);
            reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));

        } catch (UnknownHostException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Override
    public void run() {
        System.out.println("Write message to server:");

        Scanner scanner = new Scanner(System.in);
        while(scanner.next() != "quit") {
            writeToServer(scanner.next());
        }
        writer.close();
    }

    public void writeToServer(String message) {
        writer.write(message);
    }

    public void readFromServer() {
        String msg = null;

        try {
            while((msg = reader.readLine()) != null) {
                System.out.println("From server: " + msg);
            }

            reader.close();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    public static void main(String[] args) throws UnknownHostException, IOException {
        Socket s = new Socket("localhost", 5555);
        new Client(s);
    }
}

知道我做错了什么，以及如何解决我的问题？

Answer 1

socket = new Socket(serverAddress, port);

serverAddress为null，port为0。尝试在调用new Socket(serverAddress, port)

之前定义serverAddress变量和端口

或更改

socket = new Socket（serverAddress，port）;

到

this.socket = socket;

修改

您可以将构造函数更改为：

public Client(String serverAddress, int port)
{
    try {

        Socket socket = new Socket(serverAddress, port);
        writer = new PrintWriter(socket.getOutputStream(), true);
        reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));

    } catch (UnknownHostException e) {
        e.printStackTrace();
    } catch (IOException e) {
        e.printStackTrace();
    }
}

Java服务器客户端（I / O connectionException）

1 个答案:

修改