java - BufferedReader 给 Connection 重置？

标签 java networking tcp

我正在尝试使用 Java 将一些数据从客户端发送到服务器，这是我的 PlayerThread，它在新客户端连接时在服务器上运行

PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
        //Create a link to send data to the server
        BufferedReader in = new BufferedReader(
                new InputStreamReader(
                socket.getInputStream()));
        while(true)
        {
            out.println(pongData);
            String temp = in.readLine();
            if(temp == "up")
            {
                System.out.println("Up you say");
            }
        }
//There is a little more but no point to give it all

行 String temp = in.readLine(); 当客户端断开连接时给我这个错误

java.net.SocketException: Connection reset
at java.net.SocketInputStream.read(Unknown Source)
at java.net.SocketInputStream.read(Unknown Source)
at sun.nio.cs.StreamDecoder.readBytes(Unknown Source)
at sun.nio.cs.StreamDecoder.implRead(Unknown Source)
at sun.nio.cs.StreamDecoder.read(Unknown Source)
at java.io.InputStreamReader.read(Unknown Source)
at java.io.BufferedReader.fill(Unknown Source)
at java.io.BufferedReader.readLine(Unknown Source)
at java.io.BufferedReader.readLine(Unknown Source)
at Pong.PongPlayerThread.run(PongPlayerThread.java:36)

这是客户端代码

try
    {
        socket = new Socket(host, port);
        serverOut = new PrintWriter(socket.getOutputStream(), true);
        serverInput = new BufferedReader(new InputStreamReader(socket.getInputStream()));
    }
    catch (UnknownHostException e)
    {
        System.err.println("Couold not connect to host:" + host);
        System.exit(1);
    }
    catch (IOException e)
    {
        System.err.println("Could not get Input/Output from server");
        System.exit(1);
    }

    System.out.println("Connected to Server");

    while ((pos = serverInput.readLine()) != null) 
    {
        String[] posValues = pos.split(":");
        model.getBall().setX(Double.parseDouble(posValues[0]));
        model.getBall().setY(Double.parseDouble(posValues[1]));

        if(PongController.moveUp == true)
        {
            serverOut.println("up");
            PongController.moveUp = false;
        }

        //If the client presses up or down arrow, a message will be sent to the server
        //the server will then update the movement and the clients will be able to see it

    }

这段代码有效，但它似乎根本没有真正发送消息:(，如果有人能帮助我那就太棒了

Canvas

我刚刚编辑了一些代码，我发现在 PlayerThread 中有几行

if(temp.equals("up"))
            {
                System.out.println("Up you say");
            }

是问题吗，我在客户端的流在开始时设置为空，这可能是问题所在吗？发送空值？

这是更新后的版本

    while ((pos = serverInput.readLine()) != null) 
    {
        String[] posValues = pos.split(":");
        model.getBall().setX(Double.parseDouble(posValues[0]));
        model.getBall().setY(Double.parseDouble(posValues[1]));
        serverOut.println("nothing");

        if(PongController.moveUp == true)
        {
            System.out.println("Up");
            serverOut.println("up");
            PongController.moveUp = false;
        }
        else
        {
            serverOut.println("nothing");
        }

    }

但还是报错

检查 in.readLine 是否等于我得到的任何东西 这是代码

try
    {
        PrintWriter out = new PrintWriter(socket.getOutputStream(), true);
         BufferedReader in = new BufferedReader(
                    new InputStreamReader(
                    socket.getInputStream()));

         System.out.println("Checking readLine value");

         if(in.readLine() == null)
         {
             System.out.println("A ok");
         }
         else
         {
             System.out.println(":" + in.readLine());
         }

        while(true)
        {
             String temp = in.readLine();
             if(temp == "up")
             {
                    System.out.println("Up you say");
             }
            out.println(pongData);
        }
    }
    catch (IOException e) 
    {
        e.printStackTrace();
    }

这是结果

Pong
400.0:301.0:60.0:300.0:740.0:300.0
Server started
Server was setup and will try to create a socket
Data sent
Checking readLine value
Connection reset, and then followed by lots of red lines

我还能做什么？

我只是想像这样检查我的 BufferedReader

BufferedReader in = new BufferedReader(
                    new InputStreamReader(
                    socket.getInputStream()));

        System.out.println(in.toString());
        System.out.println(in.readLine());

我得到 java.io.BufferedReader@6262937c 的 in.toString 但是对于 readLine，我再次重置了连接...

快速更新，

在我的客户端代码中，如果我有这个

 while ((pos = serverInput.readLine()) != null) 
    {
        String[] posValues = pos.split(":");
        model.getBall().setX(Double.parseDouble(posValues[0]));
        model.getBall().setY(Double.parseDouble(posValues[1]));
        serverOut.println("nothing"); //<---

客户端将连接，获取乒乓球的位置，但随后它将停止从服务器接收数据并自行移动球(更新方法尚未被禁用)。 serverOut 是 

serverOut = new PrintWriter(socket.getOutputStream(), true);

最佳答案

好的，我注意到您最近问了很多关于网络的问题，我想您可能需要一些基础知识方面的帮助。这是一个极其简单的服务器:

package com;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;

public class SimpleServer implements Runnable
{    
    public SimpleServer()
    {
        started = false;
        serverSocket = null;
    }

    public void start()
    {
        if(!started)
        {
            started = true;

            try
            {
                serverSocket = new ServerSocket(PORT);
                running = true;

                serverThread = new Thread(this);
                serverThread.start();

                System.out.println("Server started!\n");
            }catch(Exception e)
            {
                e.printStackTrace();
                System.exit(0);
            }
        }
    }

    public void stop()
    {
        running = false;
        started = false;

        if(serverThread != null)
            serverThread.interrupt();
        serverThread = null;
    }

    public void run()
    {
        try
        {
            while(running)
            {
                try
                {
                    Socket client = serverSocket.accept();
                    System.out.println("Client Accepted!");

                    ClientHandler handler = new ClientHandler(client);

                    handler.sendMessage("Hello, SimpleClient!");
                    System.out.println("Sendeing client a message...");
                }catch(Exception e){e.printStackTrace();}
            }
        }catch(Exception e){e.printStackTrace();}
    }

    private boolean started;
    private boolean running;
    private ServerSocket serverSocket;
    private Thread serverThread;

    private static final int PORT = 8081;

    public static void main(String args[])
    {
        SimpleServer server = new SimpleServer();
        server.start();
    }

    public class ClientHandler implements Runnable
    {
        public ClientHandler(Socket socket)
        {
            this.socket = socket;

            try
            {
                writer = new PrintWriter(socket.getOutputStream());
                reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
                running = true;

                runningThread = new Thread(this);
                runningThread.start();
            }catch(Exception e){e.printStackTrace(); disconnect();}
        }

        public void disconnect()
        {
            running = false;
            if(runningThread != null)
                runningThread.interrupt();
            runningThread = null;

            try
            {
                reader.close();
            }catch(Exception e){}
            reader = null;

            try
            {
                writer.close();
            }catch(Exception e){}
            writer = null;
            try
            {
                socket.close();
            }catch(Exception e){}
            socket = null;
        }

        public void sendMessage(String message)
        {
            if(running)
            {
                writer.println(message);
                writer.flush();
            }
        }

        public void run()
        {
            try
            {
                String message = "";
                while((message = reader.readLine()) != null && running)
                {
                    System.out.println("Message Recieved: " + message);
                }
            }catch(Exception e){e.printStackTrace(); disconnect();}
        }

        private Socket socket;
        private PrintWriter writer;
        private BufferedReader reader;

        private Thread runningThread;
        private boolean running;
    }
}

现在是客户端:

package com;

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

public class SimpleClient implements Runnable
{
    public SimpleClient()
    {
        try
        {
            socket = new Socket("127.0.0.1", PORT);
            writer = new PrintWriter(socket.getOutputStream());
            reader = new BufferedReader(new InputStreamReader(socket.getInputStream()));
            running = true;

            runningThread = new Thread(this);
            runningThread.start();
        }catch(Exception e){e.printStackTrace(); disconnect();}
    }

    public void disconnect()
    {
        running = false;
        if(runningThread != null)
            runningThread.interrupt();
        runningThread = null;

        try
        {
            reader.close();
        }catch(Exception e){}
        reader = null;

        try
        {
            writer.close();
        }catch(Exception e){}
        writer = null;
        try
        {
            socket.close();
        }catch(Exception e){}
        socket = null;
    }

    public void sendMessage(String message)
    {
        if(running)
        {
            writer.println(message);
            writer.flush();
        }
    }

    public void run()
    {
        try
        {
            String message = "";
            while((message = reader.readLine()) != null && running)
            {
                System.out.println("Message Recieved: " + message);

                System.out.println("Sending a response!");
                sendMessage("Hello, SimpleServer!");
            }
        }catch(Exception e){e.printStackTrace(); disconnect();}
    }

    private Socket socket;
    private PrintWriter writer;
    private BufferedReader reader;

    private Thread runningThread;
    private boolean running;

    private static final int PORT = 8081;

    public static void main(String args[])
    {
        new SimpleClient();
    }
}

为了在 Java 中创建一个成功的服务器，您需要实现大量的面向对象。如果服务器不仅要处理对客户端的监听，还要处理与这些客户端之间的消息收发，那么它就太复杂了。这就是我通常使用 ClientHandler 类的原因。这个类处理所有的通信并且很容易实现。客户端和服务器永远不应该在同一个文件中，因为它们应该单独运行。

如果您不确定服务器和客户端应该如何工作，您可能也会感兴趣:

希望对您有所帮助!

约翰

关于java - BufferedReader 给 Connection 重置？，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/14880246/

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