Java套接字文件传输-文件不完整

Question

I have a problem with my file transfer from a server to client. The thing is that even how big the file is, the last bytes will not be transferred. Let say I want to download a file for 56kb, then I only receives 35kb for example.

I will provide you with some code snippets and maybe someone could see anything that is wrong.

Sender:

public void sendFile(String fileName, Socket socket) {
    try {
        try {
            File transferFile = new File(fileName);
            byte[] bytearray = new byte[(int) transferFile.length()];
            FileInputStream fin = new FileInputStream(transferFile);
            BufferedInputStream bin = new BufferedInputStream(fin);
            OutputStream os = socket.getOutputStream();
            int bytesRead = 0;

            while (-1 != (bytesRead = bin.read(bytearray, 0, bytearray.length))) {
                os.write(bytearray, 0, bytesRead);
            }

            bin.close();
            os.flush();
            socket.close();
        } catch (IOException e) {
            System.out.println("error " + e);
        }
    } catch (Exception ex) {
        System.out.println("error " + ex);
    }
}

Receiver:

public void downloadFile(Socket socket, String fName) {

    try {
        InputStream is = socket.getInputStream();

        FileOutputStream fos = new FileOutputStream(fName);
        BufferedOutputStream bos = new BufferedOutputStream(fos);

        int count;
        byte[] buffer = new byte[1024];

        while ((count = is.read(buffer)) != -1) {
            bos.write(buffer, 0, count);
        }

        bos.flush();
        bos.close();
    } catch (Exception e) {
        System.out.println("Error " + e);
    }
}

Any help is welcome, thank you.

Answer 1

while ((count = is.read(buffer)) > 0) will break the loop if is.read() returns zero.

However, you should not assume that the end of the file has been reached if zero is returned, because according to the documentation, zero is a perfectly valid value to return.

You should keep reading until -1 is returned.

Furthermore, after closing your BufferedOutputStream bos you should also close your FileOutputStream fos .