FileTransfer

🎞 A command-line interface tool of using Java Socket API transfer files

• FileTransfer
  • Usage
    • For server
    • For client
  • Features
  • 学习笔记

Usage

Note: JDK java runtime environment must be installed

For server

$ java Server -h
A tool of starting share files in current directory
Usage:
    java Server [options]
Options:
                  When no option specified, start service on default port: 2019
    -h, --help    Show help and quit
    -p <port>     Set the listening port and start service
    -l            List sharing files of current directory

For client

$ java Client -h
A tool for download/upload files from remote sharing directory
Usage:
    java Client <options>
Options:
    -h, --help    Show help
    -4            Make all connections via IPv4
    -6            Make all connections via IPv6
    -c            Use conf.properties file of current directory to start
    -l            List sharing files of remote host
    -d <file>     Download specified sharing file from remote host
    -u <file>     Upload specified file to remote host (you can drag the file to command prompt)

Features

学习笔记

• TCP 传输存在粘包问题。即发送端分两次发送数据，接收端一次性全部接收数据
• 输出流写完就要刷新。即 OutputStream.write(buffer, 0, len) 完成后最好立马 OutputStream.flush()。好处如下：
  • Socket 中可以确保一端的 OutputStream out = socket.getOutputStream() 输出流的内容可以立马被另一端 InputStream in = socket.getInputStream() 输入流取到
  • 文件流中可以确保文件输出流及时变化，即可以及时看到本地文件大小变化
• Socket 中一端关闭输出流 out.close() 可以使得另一端的 in.read(buffer) 调用得到 -1，不然 in.read(buffer) 会一直阻塞。