java - 客户端从服务器读取太多字节？

Question

我正在编写一个简单的 FTP 客户端/服务器设置。客户端应该能够从服务器检索文件并将结果作为字节流放入/retr_files/filex 中。从服务器发送适当的响应，并且 file1 确实在文件夹中创建。但是，发送(或接收)的字节过多。我在 9.6kB 文件上对此进行了测试，它在客户端生成的文件为 16.6kB。奇怪的。我觉得我在这里遗漏了一些明显的东西，有人可以帮助我吗？ 谢谢!

相关代码:

客户:

BufferedReader inFromServer_d = null;

    if(welcomeSocket!=null){
        if(!welcomeSocket.isClosed()){
            welcomeSocket.close();
        }
    }

    try {
        welcomeSocket = new ServerSocket(port);
        System.out.print("PORT " + myIP + "," + num1 + "," + num2 + "\r\n");
        out.writeBytes("PORT " + myIP + "," + num1 + "," + num2 + "\r\n");
        System.out.print(parseReply(getResponse()));
        System.out.print("RETR " + pathname + "\r\n");
        out.writeBytes("RETR " + pathname + "\r\n");
        String reply = parseReply(getResponse());
        if (reply.charAt(10)=='1') {
            System.out.print(reply);
            System.out.print(parseReply(getResponse()));

            try{
                clientSocket_d = welcomeSocket.accept();
            } catch (IOException e) {
                System.out.print("GET failed, FTP-data port not allocated.\r\n");
                System.exit(-1);
            }


                inFromServer_d = new BufferedReader(new InputStreamReader(
                        clientSocket_d.getInputStream()));


            // READ
            BufferedReader bufferedReader = inFromServer_d;
            FileWriter output = new FileWriter("retr_files/file" + retrCnt);
            BufferedWriter bufferedWriter = new BufferedWriter(output);

            String length;
            while ((length = bufferedReader.readLine()) != null) {
                bufferedWriter.write(length + "\n");
            }

            bufferedReader.close();
            bufferedWriter.close();
            clientSocket_d.close();

服务器:

//TCP CONNECT
                        DataOutputStream outToClient_d = null;
                        Socket clientSocket1 = null;


                        try {
                            ipAddress = ipAddress.substring(0, ipAddress.length()-1);
                        clientSocket1 = new Socket(ipAddress, portNumber);
                        outToClient_d = new DataOutputStream(clientSocket1.getOutputStream());
                        }

                        catch(UnknownHostException e){
                          out.writeBytes("425 Can not open data connection.\r\n");
                        }



                        BufferedReader bufferedReader = new BufferedReader(input);

                        String length;
                        while((length = bufferedReader.readLine())!=null){
                            outToClient_d.writeBytes(length+"\n");
                        }
                        out.writeBytes("250 Requested file action completed.\r\n");
                        bufferedReader.close();
                        clientSocket1.close();
                        outToClient_d.close();

}

Answer 1

不要使用 Readers 和 Writers 以及 readLine()。并非所有文件都不是文本文件，也并非所有文本文件都有换行符。使用流。