使用java套接字将文本文件从客户端发送到服务器

这是一项任务

我想听听我在哪里出问题的建议。我的目标是从文件中读取文本，将其发送到服务器并将该文本写入新文件

问题是我不太清楚怎么做，我看过很多例子，但都没有什么帮助

按原样解释程序。将要求用户输入与该代码的if语句相关的代码。我想重点关注的是代码200，它是上传文件到服务器的代码

当我运行代码时，我得到下面的错误。如果有人能告诉我哪里出了问题，我将不胜感激

    Connection request made
Enter Code: 100 = Login, 200 = Upload, 400 = Logout:
200
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 MyStreamSocket.receiveMessage(MyStreamSocket.java:50)
        at EchoClientHelper2.getEcho(EchoClientHelper2.java:34)
        at EchoClient2.main(EchoClient2.java:99)

服务器上出现以下错误：

    Waiting for a connection.
connection accepted
message received: 200
java.net.SocketException: Socket is not connected
        at java.net.Socket.getInputStream(Unknown Source)
        at EchoServer2.main(EchoServer2.java:71)

---

您的

MyStreamSocket

类不需要扩展套接字。神秘的错误消息是因为MyStreamSocket表示的套接字从未连接到任何东西。由其

套接字

成员引用的套接字是已连接的套接字。因此，当您从MyStreamSocket获取输入流时，它实际上没有连接。这将导致一个错误，这意味着客户端将关闭。这会导致套接字关闭，服务器会及时报告

使用BufferedReader会给您带来问题。它总是尽可能多地读取缓冲区中的内容，因此在文件传输开始时，它将读取“200”消息，然后读取发送的文件的前几个Kb，这些Kb将被解析为字符数据。结果将是一堆错误

我建议您现在就摆脱BufferedReader，改用DataInputStream和DataOutputStream。您可以使用writeUTF和readUTF方法发送文本命令。要发送文件，我建议使用简单的块编码

如果我给你代码可能是最简单的

首先是客户端类

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

public class EchoClient2 {

    public static void main(String[] args) {
        InputStreamReader is = new InputStreamReader(System.in);
        BufferedReader br = new BufferedReader(is);

        File file = new File("C:\\MyFile.txt");

        try {
            System.out.println("Welcome to the Echo client.\n"
                    + "What is the name of the server host?");
            String hostName = br.readLine();
            if( hostName.length() == 0 ) // if user did not enter a name
                hostName = "localhost"; // use the default host name
            System.out.println("What is the port number of the server host?");
            String portNum = br.readLine();
            if( portNum.length() == 0 ) portNum = "7"; // default port number
            MyStreamSocket socket = new MyStreamSocket(
                    InetAddress.getByName(hostName), Integer.parseInt(portNum));
            boolean done = false;
            String echo;
            while( !done ) {

                System.out.println("Enter Code: 100 = Login, 200 = Upload, 400 = Logout: ");
                String message = br.readLine();
                boolean messageOK = false;

                if( message.equals("100") ) {
                    messageOK = true;
                    System.out.println("Enter T-Number: (Use Uppercase 'T')");
                    String login = br.readLine();
                    if( login.charAt(0) == 'T' ) {
                        System.out.println("Login Worked fantastically");
                    } else {
                        System.out.println("Login Failed");
                    }
                    socket.sendMessage("100");
                }

                if( message.equals("200") ) {
                    messageOK = true;
                    socket.sendMessage("200");
                    socket.sendFile(file);
                }
                if( (message.trim()).equals("400") ) {
                    messageOK = true;
                    System.out.println("Logged Out");
                    done = true;
                    socket.sendMessage("400");
                    socket.close();
                    break;
                }

                if( ! messageOK ) {
                    System.out.println("Invalid input");
                    continue;
                }

                // get reply from server
                echo = socket.receiveMessage();
                System.out.println(echo);
            } // end while
        } // end try
        catch (Exception ex) {
            ex.printStackTrace();
        } // end catch
    } // end main
} // end class

然后您的服务器类：

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

public class EchoServer2 {
    static final String loginMessage = "Logged In";

    static final String logoutMessage = "Logged Out";


    public static void main(String[] args) {
        int serverPort = 7; // default port
        String message;

        if( args.length == 1 ) serverPort = Integer.parseInt(args[0]);
        try {
            // instantiates a stream socket for accepting
            // connections
            ServerSocket myConnectionSocket = new ServerSocket(serverPort);
            /**/System.out.println("Daytime server ready.");
            while( true ) { // forever loop
                // wait to accept a connection
                /**/System.out.println("Waiting for a connection.");
                MyStreamSocket myDataSocket = new MyStreamSocket(
                        myConnectionSocket.accept());
                /**/System.out.println("connection accepted");
                boolean done = false;
                while( !done ) {
                    message = myDataSocket.receiveMessage();

                    /**/System.out.println("message received: " + message);

                    if( (message.trim()).equals("400") ) {
                        // Session over; close the data socket.
                        myDataSocket.sendMessage(logoutMessage);
                        myDataSocket.close();
                        done = true;
                    } // end if

                    if( (message.trim()).equals("100") ) {
                        // Login
                        /**/myDataSocket.sendMessage(loginMessage);
                    } // end if

                    if( (message.trim()).equals("200") ) {

                        File outFile = new File("C:\\OutFileServer.txt");
                        myDataSocket.receiveFile(outFile);
                        myDataSocket.sendMessage("File received "+outFile.length()+" bytes");
                    }

                } // end while !done
            } // end while forever
        } // end try
        catch (Exception ex) {
            ex.printStackTrace();
        }
    } // end main
} // end class

然后，StreamSocket类：

public class MyStreamSocket {
    private Socket socket;

    private DataInputStream input;

    private DataOutputStream output;


    MyStreamSocket(InetAddress acceptorHost, int acceptorPort)
            throws SocketException, IOException {
        socket = new Socket(acceptorHost, acceptorPort);
        setStreams();
    }


    MyStreamSocket(Socket socket) throws IOException {
        this.socket = socket;
        setStreams();
    }


    private void setStreams() throws IOException {
        // get an input stream for reading from the data socket
        input = new DataInputStream(socket.getInputStream());
        output = new DataOutputStream(socket.getOutputStream());
    }


    public void sendMessage(String message) throws IOException {
        output.writeUTF(message);
        output.flush();
    } // end sendMessage


    public String receiveMessage() throws IOException {
        String message = input.readUTF();
        return message;
    } // end receiveMessage


    public void close() throws IOException {
        socket.close();
    }


    public void sendFile(File file) throws IOException {
        FileInputStream fileIn = new FileInputStream(file);
        byte[] buf = new byte[Short.MAX_VALUE];
        int bytesRead;        
        while( (bytesRead = fileIn.read(buf)) != -1 ) {
            output.writeShort(bytesRead);
            output.write(buf,0,bytesRead);
        }
        output.writeShort(-1);
        fileIn.close();
    }



    public void receiveFile(File file) throws IOException {
        FileOutputStream fileOut = new FileOutputStream(file);
        byte[] buf = new byte[Short.MAX_VALUE];
        int bytesSent;        
        while( (bytesSent = input.readShort()) != -1 ) {
            input.readFully(buf,0,bytesSent);
            fileOut.write(buf,0,bytesSent);
        }
        fileOut.close();
    }    
} // end class

放弃“helper”类。这对你没有帮助