java - 当我运行客户端-服务器程序时，我得到 ArrayIndexOutofBoundException

Question

我正在编写我的第一个java客户端/服务器程序，它只是与服务器建立连接，当我运行程序时，应该打印IP地址和端口号。但是当我运行服务器程序时出现错误。

服务器.java

package serverpro;
import java.io.*;
import java.net.*;

public class Server{
 static InetAddress ip;
 public static final String HOST="localhost";
 public static final int PORT= 4444; 


public static void main(String a[]) throws Exception {
System.out.println("starting server..");
System.out.println("Initializing Connection..");

try (
        ServerSocket serverSocket = new ServerSocket(PORT);
        Socket clientSocket = serverSocket.accept();

        //BufferedReader in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
        //PrintWriter out = new PrintWriter(clientSocket.getOutputStream(), true);
) {
    ip = InetAddress.getLocalHost();
    System.out.println("InetAdress " + ip.getHostAddress() + " : " + clientSocket.getPort());


} catch (Exception e) {
    System.err.println("Exception in starting server: " + e.getMessage());
}
}
 }

客户端.java

package serverpro;

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

 public class Client {
 public static void main(String[] args) throws IOException {
try (
        Socket client = new Socket(Server.HOST, Server.PORT);
        PrintWriter out = new PrintWriter(client.getOutputStream(), true);

        BufferedReader in = new BufferedReader(new InputStreamReader(client.getInputStream()));
        BufferedReader stdIn = new BufferedReader(new InputStreamReader(System.in));
) {
    String inputLine;
    while ((inputLine = stdIn.readLine()) != null) {

        if ("exit".equals(inputLine)) {
            out.println("exit");
            break;
        }

        out.println(inputLine);
        out.flush();

        final String response = in.readLine();
        System.out.println(response);
    }
} catch (UnknownHostException e) {
    System.err.println("Don't know about host: localhost.");
    System.exit(1);
} catch (IOException e) {
    System.err.println("Couldn't get I/O for the connection to: localhost.");
    System.exit(1);
}

}}

现在，当我首先运行 ServerProgram 时，我得到以下输出

运行:

Entered server console..
Initializing Connection..

但是当我运行客户端输出时，它显示为 null

运行:

Answer 1

我猜您没有使用任何参数启动程序，因此您的 args 数组为空。使用参数启动程序或找到不同的方法来获取服务器名称和端口。