Beyond the Basics - TCP/IP Sockets in Java Practical Guide for Programmers - page 87

and writes the compressed data until the client performs a shutdown, causing the server read
to return 1, indicating an end-of-stream. The server then closes the connection and exits.

After the client calls shutdownOutput() , it needs to read any remaining compressed bytes from
the server.
Our compression client, CompressClient.java , implements the client side of the compres-
sion protocol. The uncompressed bytes are read from the file specified on the command line,
and the compressed bytes are written to a new file. If the uncompressed filename is “ data ”, the
compressed filename is “ data.gz ”. Note that this implementation works for small files, but that
there is a flaw that causes deadlock for large files. (We discuss and correct this shortcoming
in Section 5.2.)

−

CompressClient.java

0 import java.net.*; // for Socket
1 import java.io.*;

// for IOException and [File]Input/OutputStream

2
3 public class CompressClient {
4
5

public static final int BUFSIZE = 256; // Size of read buffer

6
7

public static void main(String[] args) throws IOException {

8
9

if (args.length != 3) // Test for correct # of args

10

throw new IllegalArgumentException("Parameter(s): <Server> <Port> <File>");

11
12

String server = args[0]; // Server name or IP address

13

int port = Integer.parseInt(args[1]); // Server port

14

String filename = args[2]; // File to read data from

15
16 // Open input and output file (named input.gz)

17 FileInputStream fileIn = new FileInputStream(filename);

18 FileOutputStream fileOut = new FileOutputStream(filename + ".gz");

19
20

// Create socket connected to server on specified port

21 Socket sock = new Socket(server, port);

22
23 // Send uncompressed byte stream to server

24

sendBytes(sock, fileIn);

25
26

// Receive compressed byte stream from server

27

InputStream sockIn = sock.getInputStream();

28

int bytesRead; // Number of bytes read

29

byte[] buffer = new byte[BUFSIZE]; // Byte buffer

30

while ((bytesRead = sockIn.read(buffer)) != −1) {

31

fileOut.write(buffer, 0, bytesRead);