[펌]Transfer a file via Socket

출처 : http://www.rgagnon.com/javadetails/java-0542.html
 
A client module connects to a server then a file is sent to the client. This exemple is very simple with no authentication and hard-coded filename!

First a server module.

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

public class FileServer {
  public static void main (String [] args ) throws IOException {
    // create socket
    ServerSocket servsock = new ServerSocket(13267);
    while (true) {
      System.out.println("Waiting...");

      Socket sock = servsock.accept();
      System.out.println("Accepted connection : " + sock);

      // sendfile
      File myFile = new File ("source.pdf");
      byte [] mybytearray  = new byte [(int)myFile.length()];
      FileInputStream fis = new FileInputStream(myFile);
      BufferedInputStream bis = new BufferedInputStream(fis);
      bis.read(mybytearray,0,mybytearray.length);
      OutputStream os = sock.getOutputStream();
      System.out.println("Sending...");
      os.write(mybytearray,0,mybytearray.length);
      os.flush();
      sock.close();
      }
    }
}

The client module

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

public class FileClient{
  public static void main (String [] args ) throws IOException {
    int filesize=6022386; // filesize temporary hardcoded

    long start = System.currentTimeMillis();
    int bytesRead;
    int current = 0;
    // localhost for testing
    Socket sock = new Socket("127.0.0.1",13267);
    System.out.println("Connecting...");

    // receive file
    byte [] mybytearray  = new byte [filesize];
    InputStream is = sock.getInputStream();
    FileOutputStream fos = new FileOutputStream("source-copy.pdf");
    BufferedOutputStream bos = new BufferedOutputStream(fos);
    bytesRead = is.read(mybytearray,0,mybytearray.length);
    current = bytesRead;

    // thanks to A. Cádiz for the bug fix
    do {
       bytesRead =
          is.read(mybytearray, current, (mybytearray.length-current));
       if(bytesRead >= 0) current += bytesRead;
    } while(bytesRead > -1);

    bos.write(mybytearray, 0 , current);
    bos.flush();
    long end = System.currentTimeMillis();
    System.out.println(end-start);
    bos.close();
    sock.close();
  }
}

Thanks to s.gondi for the fix (bos.flush())!