84 lines
2.5 KiB
Java
84 lines
2.5 KiB
Java
// compression/ZipCompress.java
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// (c)2021 MindView LLC: see Copyright.txt
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// We make no guarantees that this code is fit for any purpose.
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// Visit http://OnJava8.com for more book information.
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// Uses Zip compression to compress any
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// number of files given on the command line
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// {java ZipCompress ZipCompress.java}
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// {VisuallyInspectOutput}
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import java.util.zip.*;
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import java.io.*;
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import java.util.*;
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public class ZipCompress {
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public static void main(String[] args) {
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try(
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FileOutputStream f =
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new FileOutputStream("test.zip");
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CheckedOutputStream csum =
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new CheckedOutputStream(f, new Adler32());
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ZipOutputStream zos = new ZipOutputStream(csum);
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BufferedOutputStream out =
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new BufferedOutputStream(zos)
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) {
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zos.setComment("A test of Java Zipping");
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// No corresponding getComment(), though.
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for(String arg : args) {
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System.out.println("Writing file " + arg);
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try(
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InputStream in = new BufferedInputStream(
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new FileInputStream(arg))
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) {
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zos.putNextEntry(new ZipEntry(arg));
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int c;
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while((c = in.read()) != -1)
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out.write(c);
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}
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out.flush();
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}
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// Checksum valid only after the file is closed!
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System.out.println(
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"Checksum: " + csum.getChecksum().getValue());
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} catch(IOException e) {
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throw new RuntimeException(e);
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}
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// Now extract the files:
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System.out.println("Reading file");
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try(
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FileInputStream fi =
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new FileInputStream("test.zip");
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CheckedInputStream csumi =
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new CheckedInputStream(fi, new Adler32());
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ZipInputStream in2 = new ZipInputStream(csumi);
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BufferedInputStream bis =
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new BufferedInputStream(in2)
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) {
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ZipEntry ze;
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while((ze = in2.getNextEntry()) != null) {
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System.out.println("Reading file " + ze);
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int x;
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while((x = bis.read()) != -1)
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System.out.write(x);
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}
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if(args.length == 1)
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System.out.println(
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"Checksum: "+csumi.getChecksum().getValue());
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} catch(IOException e) {
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throw new RuntimeException(e);
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}
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// Alternative way to open and read Zip files:
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try(
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ZipFile zf = new ZipFile("test.zip")
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) {
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Enumeration e = zf.entries();
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while(e.hasMoreElements()) {
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ZipEntry ze2 = (ZipEntry)e.nextElement();
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System.out.println("File: " + ze2);
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// ... and extract the data as before
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}
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} catch(IOException e) {
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throw new RuntimeException(e);
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}
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}
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}
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