Java套接字编程 - 套接字在连接完成之前超时

Question

我有一个套接字编程代码..

Server Program

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

public class GreetingServer extends Thread
{
private static int port;
  private ServerSocket serverSocket;

  public GreetingServer(int port) throws IOException
   {
  serverSocket = new ServerSocket(port);
  serverSocket.setSoTimeout(50000);
   }

 public void run()
  {
     while(true)
     {
        try
         {
           System.out.println("Waiting for client on port " +
           serverSocket.getLocalPort() + "...");
           Socket server = serverSocket.accept();
           System.out.println("Just connected to "
                + server.getRemoteSocketAddress());
           DataInputStream in =
              new DataInputStream(server.getInputStream());
           System.out.println(in.readUTF());
           DataOutputStream out =
             new DataOutputStream(server.getOutputStream());
            out.writeUTF("Thank you for connecting to "
             + server.getLocalSocketAddress() + "\nGoodbye!");
        server.close();
     }catch(SocketTimeoutException s)
     {
        System.out.println("Socket timed out!");
        break;
     }catch(IOException e)
     {
        e.printStackTrace();
        break;
       }
    }
 }
     public static void main(String [] args)
     {
       port=9000;
       try
     {
       Thread t = new GreetingServer(port);
       t.start();
     }catch(IOException e)
    {
      e.printStackTrace();
    }
   }
 }

而客户端代码是......

import java.io.*;
import java.net.*;
public class GreetingClient
 {
   private static String serverName;
   public static void main(String [] args)
    {
      String sName = "MyServerName";
      int port = 9000;
      try
       {
        System.out.println("Connecting to " + sName
                         + " on port " + port);
     Socket client = new Socket(sName, port);
     System.out.println("Just connected to "
                  + client.getRemoteSocketAddress());
     OutputStream outToServer = client.getOutputStream();
     DataOutputStream out =
                   new DataOutputStream(outToServer);

     out.writeUTF("Hello from "
                  + client.getLocalSocketAddress());
     InputStream inFromServer = client.getInputStream();
     DataInputStream in =
                    new DataInputStream(inFromServer);
     System.out.println("Server says " + in.readUTF());
     client.close();
  }catch(IOException e)
    {
    }
  }
 }

代码编译得很好.但是当我运行程序时,首先是服务器,然后是客户端,服务器会显示该程序

Waiting for client on port 9000...
Socket timed out!

并且客户端显示

Connecting to MyServerName on port 9000

代码有什么问题？我已经尝试增加和减少超时值,但它提供相同的输出.

Answer 1

代码有什么问题？

您的代码没有任何问题.您设置了50秒的接受超时,接受阻止50秒而没有客户端尝试连接,因此SocketTimeoutException抛出了a .这里的一切都按设计工作.

当然有可能:

• 你的接受超时太短了
• 你不想因为接受超时而中止你的服务器
• 你根本不想要接受超时.

所有这些都是取决于您的要求的设计决策.

您也可能在客户端中输入了错误的主机名,但是因为您忽略了客户端中的异常:

catch(IOException e)
{
}

你永远无法找到答案.千万不要忽视IOExceptions.