如何通过Java在套接字上发送文件列表 [英] How to send a list of files over a socket in Java

问题描述

我已使用代码此处通过套接字发送单个文件。但是，我需要能够通过套接字发送多个文件（基本上是目录中的所有文件），并让客户端识别文件之间的分离方式。坦率地说，我完全不知道该做什么。任何提示都会有所帮助。

I have used the code here to send an individual file over a socket. However, I need to be able to send multiple files (basically all files in a directory) over the socket and have the client recognize how the separation between files. Frankly, I am at a complete loss for what to do. Any tips would be helpful.

注意1：我需要一种方法在一个连续的流中发送文件，客户端可以将这些文件分隔成个人文件。它不能依赖客户的个别请求。

NOTE 1: I need a way to send the files in one continuous stream that the client can segregate into individual files. It cannot rely on individual requests from the client.

注意2：要回答一个问题，我很确定我会在评论中加入，不，这是 NOT 作业。

NOTE 2: To answer a question I am pretty sure I will get in the comments, no, this is NOT homework.

编辑有人建议我可以发送文件的大小在文件本身之前。我怎么能这样做，因为通过套接字发送文件总是以预定的字节数组或单个字节完成，而不是由 File.length（）

EDIT it has been suggested that I could send the size of the file before the file itself. How can I do this, as sending a file over the socket is always done in either a predetermined array of bytes, or a single byte individually, rather than the long returned by File.length()

推荐答案

以下是完整实施：

发件人方：

String directory = ...;
String hostDomain = ...;
int port = ...;

File[] files = new File(directory).listFiles();

Socket socket = new Socket(InetAddress.getByName(hostDomain), port);

BufferedOutputStream bos = new BufferedOutputStream(socket.getOutputStream());
DataOutputStream dos = new DataOutputStream(bos);

dos.writeInt(files.length);

for(File file : files)
{
    long length = file.length();
    dos.writeLong(length);

    String name = file.getName();
    dos.writeUTF(name);

    FileInputStream fis = new FileInputStream(file);
    BufferedInputStream bis = new BufferedInputStream(fis);

    int theByte = 0;
    while((theByte = bis.read()) != -1) bos.write(theByte);

    bis.close();
}

dos.close();

接收方：

String dirPath = ...;

ServerSocket serverSocket = ...;
Socket socket = serverSocket.accept();

BufferedInputStream bis = new BufferedInputStream(socket.getInputStream());
DataInputStream dis = new DataInputStream(bis);

int filesCount = dis.readInt();
File[] files = new File[filesCount];

for(int i = 0; i < filesCount; i++)
{
    long fileLength = dis.readLong();
    String fileName = dis.readUTF();

    files[i] = new File(dirPath + "/" + fileName);

    FileOutputStream fos = new FileOutputStream(files[i]);
    BufferedOutputStream bos = new BufferedOutputStream(fos);

    for(int j = 0; j < fileLength; j++) bos.write(bis.read());

    bos.close();
}

dis.close();

我没有测试它，但我希望它能运作！

I did not test it, but I hope it will work!

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