Java服务器，客户端程序

Question

下面的代码应该允许用户输入一个URL，它也返回该网站的IP地址，但它不工作。

该应用程序是一个控制台应用程序。我曾经一起工作，但我不知道为什么它现在不起作用。

这里是我得到的错误，当用户进入一个网站，从

IOException: java.net.SocketException: Connection reset 

在这里得到的IP地址是我的客户端代码

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

public class Client { 
    public static void main(String[] args) { 

     String hostname = "localhost"; 
     int port = 6052; 

     if (args.length > 0) { 
      hostname = args[0]; 
     } 

     Socket clientSocket = null; 
     PrintWriter os = null; 
     BufferedReader is = null; 


     try { 
      clientSocket = new Socket(hostname, port); 
      os = new PrintWriter(clientSocket.getOutputStream(), true); 
      is = new BufferedReader(new InputStreamReader(clientSocket.getInputStream())); 
     } catch (UnknownHostException e) { 
      System.err.println("Don't know about host: " + hostname); 
     } catch (IOException e) { 
      System.err.println("Couldn't get I/O for the connection to: " + hostname); 
     } 


     if (clientSocket == null || os == null || is == null) { 
      System.err.println("Something is really wrong. "); 
      return; 
     } 

     try { 
      if (args.length != 2) { 

       System.out.print("Enter a www web address (must have www!) "); 
       BufferedReader br = new BufferedReader(new InputSreamReader(Sy.in)) 
       String keyboardInput = br.readLine(); 
       os.println(keyboardInput); 

      } else { 
       os.println(args[1]); 
      } 
      String responseLine = is.readLine(); 
      System.out.println("The IP address of " + args[1] + "is" + responseLine); 


     } catch (UnknownHostException e) { 
      System.err.println("Trying to connect to host: " + e); 
     } catch (IOException e) { 
      System.err.println("IOException: " + e); 
     } 
    } 
} 

这里是我的服务器代码

import java.io.IOException; 
import java.net.ServerSocket; 
import java.net.Socket; 

public class Server { 
    public static void main(String args[]) { 
     int port = 6052; 
     Server server = new Server(port); 
     server.startServer(); 
    } 

    ServerSocket echoServer = null; 
    Socket clientSocket = null; 
    int numConnections = 0; 
    int port; 

    public Server(int port) { 
     this.port = port; 
    } 

    public void stopServer() { 
     System.out.println("Server working hold on a min."); 
     System.exit(0); 
    } 

    public void startServer() { 
     try { 
      echoServer = new ServerSocket(port); 
     } catch (IOException e) { 
      e.printStackTrace(); 
     } 

     System.out.println("Server is now started and is waiting for Clients."); 


     while (true) { 
      try { 
       clientSocket = echoServer.accept(); 
       numConnections++; 
       new Thread(new ServerConnection(clientSocket, numConnections, 
         this)).start(); 
      } catch (IOException e) { 
       System.out.println(e); 
      } 
     } 
    } 
} 




class ServerConnection implements Runnable { 
private static BufferedReader is; 
private static PrintStream os; 
private static Socket clientSocket; 
private static int id; 
private static Server server; 

public ServerConnection(Socket clientSocket, int id, Server server) { 
this.clientSocket = clientSocket; 
this.id = id; 
this.server = server; 
System.out.println("Connection " + id + " established with: " + clientSocket); 
try { 
    is = new BufferedReader(new InputStreamReader(clientSocket.getInputStream())); 
    os = new PrintStream(clientSocket.getOutputStream()); 
} catch (IOException e) { 
    System.out.println(e); 
} 
} 




public void run() { 
    String line; 
try { 
    boolean serverStop = false; 

      line = is.readLine(); 
    System.out.println("Received " + line + " from Connection " + id + "."); 

       InetAddress hostAddress = InetAddress.getByName(line); 
       String IPaddress = hostAddress.getHostAddress(); 
       os.println(IPaddress); 

      is.close(); 
     os.close(); 
    clientSocket.close(); 
} catch (IOException e) { 
    e.printStackTrace(); 
} 
} 
} 

Answer 1

不带任何参数，主机会localhost，用户将被propted一个网伊特。 ArrayOutOfBoundsException，因为你没有检查参数。

有一个参数，它是主机。传递网站将无法正常工作，因为该网站无法按预期工作。

两个参数运行，它的工作原理，如果第一个参数是localhost。