Implementing Simple Java GZIP Utility
This examaple shows how to implement a GZIP program in Java as a command-line utility. It is demonstrating the use of Java I/O streams and shows the simplicity of plugging one stream type into another.
import java.io.*;
import java.util.*;
import java.util.zip.*;
public class ZIPMachine {
public static void zipFile(String fileName) throws IOException {
FileInputStream in = new FileInputStream(fileName);
BufferedInputStream in2 = new BufferedInputStream(in);
FileOutputStream out = new FileOutputStream(fileName + ".zip");
GZIPOutputStream zipOut = new GZIPOutputStream(out);
BufferedOutputStream out2 = new BufferedOutputStream(zipOut);
int chunk;
while ((chunk = in2.read()) != -1) {
out2.write(chunk);
}
out2.close();
zipOut.close();
out.close();
System.out.println("Wrote: " + fileName + ".zip");
}
public static void unzipFile(String fileName) throws IOException {
FileInputStream in = new FileInputStream(fileName);
GZIPInputStream inZip = new GZIPInputStream(in);
BufferedInputStream in2 = new BufferedInputStream(inZip);
FileOutputStream out = new FileOutputStream(fileName
.replace(".zip", ""));
BufferedOutputStream out2 = new BufferedOutputStream(out);
int chunk;
while ((chunk = in2.read()) != -1) {
out2.write(chunk);
}
out2.close();
out.close();
System.out.println("Wrote: " + fileName.replace(".zip", ""));
}
public static void main(String[] args) {
try {
if (args.length == 1) {
zipFile(args[0]);
} else if (args.length == 2 && args[0].equals("-unzip")) {
unzipFile(args[1]);
} else {
System.out.println("Usage: zip [-unzip] file_name");
}
} catch (IOException e) {
System.out.println("An I/O error occured:");
System.out.println(e.toString());
e.printStackTrace();
}
}
}
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