java DataOutputStream异常

Question

第二次在第二次键入内容时（在键入主机名之后）在第24行中引发了异常-服务器正常运行。 码

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

class TCPclient {
    public static void main(String[] args) throws Exception {
        String hostname, msg;
        InetAddress hostaddress;
        BufferedReader inFromUser = new BufferedReader (new InputStreamReader(System.in));
        System.out.println("Please type host\n");
        hostname = inFromUser.readLine();   //I type localhost
        hostaddress = InetAddress.getByName(hostname);
        Socket cSocket = new Socket(hostaddress, 44444);
        String cAddress = cSocket.getLocalSocketAddress().toString();
        DataOutputStream outToServer = new DataOutputStream (cSocket.getOutputStream());
        while (true)
        {
            msg = inFromUser.readLine();
            System.out.println(msg);
            if (msg.equals("exit"))
            {
                System.out.println("exit");
                break;
            }
            outToServer.writeBytes(cAddress + " said : " + msg + '\n'); //this line throws an exception the second time it runs
        }
        cSocket.close();
    }
}

我是Java的新手，所以我想念一些显而易见的东西。 异常读取：

线程“主”中的异常java.net.SocketException：软件导致连接中止：java处java.net.SocketOutputStream.socketWrite0（本机方法）处的java.net.SocketOutputStream.socketWrite0（本机方法）处的套接字写入错误。 net.SocketOutputStream.write（SocketOutputStream.java:115）位于java.io.DataOutputStream.writeBytes（DataOutputStream.java:259）位于TCPclient.main（TCPClient.java:52）Java结果：1

服务器：

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

class TCPServer {
   public static void main(String argv[]) throws Exception {
      String clientSentence;
      ServerSocket welcomeSocket = new ServerSocket(44444);
      while(true) {
         Socket connectionSocket = welcomeSocket.accept();
         BufferedReader inFromClient = new BufferedReader(
                new InputStreamReader(connectionSocket.getInputStream( ) ) );
         clientSentence = inFromClient.readLine();
         System.out.println(clientSentence + "\n");
      }
   }
}

Answer 1

您的客户端创建一个套接字，并一遍又一遍地写入该套接字。 另一方面，您的服务器会执行以下操作：

ServerSocket welcomeSocket = new ServerSocket(44444);
while(true) {
   Socket connectionSocket = welcomeSocket.accept();

那接受传入的连接，读取一行，然后放弃它（我猜想当垃圾被垃圾回收时，套接字的终结将关闭连接）。 然后，它等待一个新的连接。

因此，要解决您眼前的问题，请尝试移动

    Socket connectionSocket = welcomeSocket.accept();
    BufferedReader inFromClient = new BufferedReader(
            new InputStreamReader(connectionSocket.getInputStream( ) ) );

在while循环之前。

Answer 2

您在输入第二行之间需要等待多长时间？ 它可能与套接字空闲有关。

同样，使用这样的服务器代码，您只会看到第一条消息。 尝试这个：

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

class TCPServer {
    public static void main(String argv[]) throws Exception {
        String clientSentence;
        ServerSocket welcomeSocket = new ServerSocket(44444);
        Socket connectionSocket = welcomeSocket.accept();
        BufferedReader inFromClient = new BufferedReader(new InputStreamReader(connectionSocket.getInputStream()));
        while (true) {
            clientSentence = inFromClient.readLine();
            System.out.println(clientSentence + "\n");
        }
    }
}

Answer 3

尝试：

while (true)
{
    if(inFromUser.readLine() != null)
    {        
        msg = inFromUser.readLine();

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

        outToServer.writeBytes(cAddress + " said : " + msg + "\n");
    }
}

注意更改：

if(inFromUser.readLine() != null)
{ 

和

... "\n"); 

不

... '\n');

试一试。 这可能是一个简单的解决方案，但这是:)