Java 套接字写入错误

Java Socket Write Error

提问by user1767061

I'm getting a "Socket Write Error". While scouting around on StackOverflow I found some suggestions for using flush(); method to send bytes through the stream. The problem I'm having is that after using the flush(); method, I still get the error. I'm not sure what is causing the problem. Any ideas? This is the complete client code:

我收到“套接字写入错误”。在 StackOverflow 上四处寻找时，我发现了一些使用 flush(); 的建议。通过流发送字节的方法。我遇到的问题是在使用了 flush(); 之后。方法，我仍然收到错误。我不确定是什么导致了这个问题。有任何想法吗？这是完整的客户端代码：

import java.io.*;
import java.net.*;
import java.util.ArrayList;
import java.util.Scanner;

public class TCPClient {

   public static void main(String[] args) throws Exception {

      String origSentence;
      String modifiedSentence;
      boolean win = false;
      boolean lose = false;

      //BufferedReader inFromUser;
      //inFromUser = new BufferedReader(new InputStreamReader(System.in));
      Scanner inFromUser = new Scanner(System.in);
      Socket clientSocket = new Socket("10.64.121.145", 6784);
      boolean first = true;
      DataOutputStream outToServer =
              new DataOutputStream(clientSocket.getOutputStream());
      origSentence = inFromUser.nextLine();
      outToServer.writeBytes(origSentence + '\n');
      outToServer.flush();

      Scanner inFromServer = new Scanner(clientSocket.getInputStream());
      modifiedSentence = inFromServer.nextLine();
      GUI gui = new GUI(Integer.parseInt(modifiedSentence));
      System.out.println("The word is " + modifiedSentence + " letters long. Pick a letter!");
      gui.isNotSolved();

      while (win != true && lose != true) {
         origSentence = inFromUser.nextLine();
         System.out.println(origSentence);
         outToServer.writeBytes(origSentence + '\n'); //The failure is on this line
         outToServer.flush();
         modifiedSentence = inFromServer.nextLine();
         if (modifiedSentence.equals(""))//guess not in word so add a miss
         {
            if (gui.addMiss(origSentence) == false) {
               lose = true;
            }
         }
         if (!modifiedSentence.equals(""))//guess is in word so display where letter occurs
         {
            ArrayList<Character> list = new ArrayList<Character>();
            int length = modifiedSentence.length();
            for (int i = 0; i < length; i++) {
               list.add(modifiedSentence.charAt(i));
            }
            for (char c : list) {
               if (c == ' ') {
                  list.remove(c);
               }
            }
            for (int i = 0; i < list.size(); i++) {
               String s = list.get(i).toString();
               gui.addLetter(origSentence.charAt(0), Integer.parseInt(s));
            }

         }

         if (gui.isNotSolved() == false)//game won send server "won" message to terminate connection
         {
            String won = "won";
            outToServer.writeBytes(won);
            outToServer.flush();
         }

         if (lose == true)//game lost send server "lost" message to
         {            //have server send the word to display for player
            String lost = "lost";
            outToServer.writeBytes(lost);
            gui.setWord(modifiedSentence);
            outToServer.flush();
         }
      }
      clientSocket.close();

   }
}

... the code continues but it doesn't seem to make it to the rest of the code anyway. I'm a bit lost as to why it keeps failing. I flush() after the first use of outToServer but on the second use it fails. I'm guessing this is a Client-side problem. Any help? Thanks. Here is the Server Code:

...代码继续，但它似乎并没有让它进入代码的其余部分。我有点不明白为什么它总是失败。我在第一次使用 outToServer 后刷新（），但在第二次使用时它失败了。我猜这是一个客户端问题。有什么帮助吗？谢谢。这是服务器代码：

import java.io.*;
import java.net.*;
import java.util.Scanner;

public class TCPServer {

   public static void main(String[] args) throws Exception {
      String clientSentence;
      Word word = new Word();
      int wordLen = word.getLength();
      ServerSocket welcomeSocket = new ServerSocket(6784);
      System.out.println(InetAddress.getLocalHost());
      boolean begin = true;

      while (true) {
         Socket connSocket = welcomeSocket.accept();
         Scanner inFromClient = new Scanner(connSocket.getInputStream());
         clientSentence = inFromClient.nextLine(); //cap would go after this
         DataOutputStream outToClient =
                 new DataOutputStream(connSocket.getOutputStream());

         if (begin == true) {
            //DataOutputStream outToClient =
            //new DataOutputStream(connSocket.getOutputStream());
            System.out.println("begin " + word.getWord());
            outToClient.writeBytes("" + word.getLength());
            outToClient.flush();
         }
         if (begin == false) {
            System.out.println("hello");
            //DataOutputStream outToClient =
            //new DataOutputStream(connSocket.getOutputStream());
            String pos = word.getSpots(clientSentence.charAt(0));
            outToClient.writeBytes(pos);
            outToClient.flush();
         }
         if (clientSentence.equals("lost")) {
            outToClient.writeBytes(word.getWord());
            outToClient.flush();
         }
         if (clientSentence.equals("won")) {
            connSocket.close();
         }
         begin = false;
         connSocket.close();
      }


   }
}

Here is the error:

这是错误：

Exception in thread "main" h //Ignore the 'h', it's just a print statement checking input
java.net.SocketException: Software caused connection abort: socket write error
at java.net.SocketOutputStream.socketWrite0(Native Method)
at java.net.SocketOutputStream.socketWrite(Unknown Source)
at java.net.SocketOutputStream.write(Unknown Source)
at java.io.DataOutputStream.writeBytes(Unknown Source)
at TCPClient.main(TCPClient.java:35)

The error now is:
Exception in thread "main" java.net.ConnectException: Connection timed out: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(Unknown Source)
at java.net.PlainSocketImpl.connectToAddress(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.SocksSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at TCPClient.main(TCPClient.java:17)

回答by JB Nizet

You're closing the connection in the server immediately:

您正在立即关闭服务器中的连接：

Socket connSocket = welcomeSocket.accept();
Scanner inFromClient = new Scanner(connSocket.getInputStream());
clientSentence = inFromClient.nextLine(); //cap would go after this
DataOutputStream outToClient =
    new DataOutputStream(connSocket.getOutputStream());

[...]
connSocket.close();

So obviously, as soon as the first line from the client has been read by the server and the response has been sent, the connection is closed, and the client can't send anything more.

很明显，一旦服务器读取了客户端的第一行并发送了响应，连接就会关闭，客户端无法再发送任何内容。

回答by saurcery

Should work with below changes in the server code:

应该适用于服务器代码中的以下更改：

Socket connSocket = welcomeSocket.accept();
Scanner inFromClient = new Scanner(connSocket.getInputStream());
DataOutputStream outToClient = new DataOutputStream(connSocket.getOutputStream());
while (inFromClient.hasNext()) {
    clientSentence = inFromClient.nextLine(); //cap would go after this
    System.out.println("received from client: "+clientSentence);
}
.
.
.
.
connSocket.close();

Your client creates IO stream just once while server did it for every iteration so no connection could be established.

您的客户端只创建一次 IO 流，而服务器为每次迭代都创建一次，因此无法建立连接。