使用 GZIP 进行压缩和解压缩代码,Java代码库,德仔网

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【Java】使用 GZIP 进行压缩和解压缩
作者:禹福 / 发布于2015/1/12/ 547

	import java.util.zip.GZIPOutputStream;
	import java.io.FileOutputStream;
	import java.io.FileInputStream;
	import java.io.FileNotFoundException;
	import java.io.IOException;

	/**
	* -----------------------------------------------------------------------------
	* Used to provide an example of compressing a file using the GZIP Format.
	*
	* @version 1.0
	* @author Jeffrey M. Hunter (jhunter@idevelopment.info)
	* @author http://www.idevelopment.info
	* -----------------------------------------------------------------------------
	*/

	public class CompressFileGZIP {

	 /**
	 * Perform file compression.
	 * @param inFileName Name of the file to be compressed
	 */
	 private static void doCompressFile(String inFileName) {

	 try {

	 System.out.println("Creating the GZIP output stream.");
	 String outFileName = inFileName + ".gz";
	 GZIPOutputStream out = null;
	 try {
	 out = new GZIPOutputStream(new FileOutputStream(outFileName));
	 } catch(FileNotFoundException e) {
	 System.err.println("Could not create file: " + outFileName);
	 System.exit(1);
	 }

	 System.out.println("Opening the input file.");
	 FileInputStream in = null;
	 try {
	 in = new FileInputStream(inFileName);
	 } catch (FileNotFoundException e) {
	 System.err.println("File not found. " + inFileName);
	 System.exit(1);
	 }

	 System.out.println("Transfering bytes from input file to GZIP Format.");
	 byte[] buf = new byte[1024];
	 int len;
	 while((len = in.read(buf)) > 0) {
	 out.write(buf, 0, len);
	 }
	 in.close();

	 System.out.println("Completing the GZIP file");
	 out.finish();
	 out.close();

	 } catch (IOException e) {
	 e.printStackTrace();
	 System.exit(1);
	 }

	 }

	 /**
	 * Sole entry point to the class and application.
	 * @param args Array of String arguments.
	 */
	 public static void main(String[] args) {

	 if (args.length != 1) {
	 System.err.println("Usage: java CompressFileGZIP filename");
	 } else {
	 doCompressFile(args[0]);
	 }

	 }

	}
	UncompressFileGZIP.java

	import java.util.zip.GZIPInputStream;
	import java.io.FileOutputStream;
	import java.io.FileInputStream;
	import java.io.FileNotFoundException;
	import java.io.IOException;

	/**
	* -----------------------------------------------------------------------------
	* Used to provide an example of uncompressing a file in the GZIP Format.
	*
	* @version 1.0
	* @author Jeffrey M. Hunter (jhunter@idevelopment.info)
	* @author http://www.idevelopment.info
	* -----------------------------------------------------------------------------
	*/

	public class UncompressFileGZIP {

	 /**
	 * Uncompress the incoming file.
	 * @param inFileName Name of the file to be uncompressed
	 */
	 private static void doUncompressFile(String inFileName) {

	 try {

	 if (!getExtension(inFileName).equalsIgnoreCase("gz")) {
	 System.err.println("File name must have extension of \".gz\"");
	 System.exit(1);
	 }

	 System.out.println("Opening the compressed file.");
	 GZIPInputStream in = null;
	 try {
	 in = new GZIPInputStream(new FileInputStream(inFileName));
	 } catch(FileNotFoundException e) {
	 System.err.println("File not found. " + inFileName);
	 System.exit(1);
	 }

	 System.out.println("Open the output file.");
	 String outFileName = getFileName(inFileName);
	 FileOutputStream out = null;
	 try {
	 out = new FileOutputStream(outFileName);
	 } catch (FileNotFoundException e) {
	 System.err.println("Could not write to file. " + outFileName);
	 System.exit(1);
	 }

	 System.out.println("Transfering bytes from compressed file to the output file.");
	 byte[] buf = new byte[1024];
	 int len;
	 while((len = in.read(buf)) > 0) {
	 out.write(buf, 0, len);
	 }

	 System.out.println("Closing the file and stream");
	 in.close();
	 out.close();

	 } catch (IOException e) {
	 e.printStackTrace();
	 System.exit(1);
	 }

	 }

	 /**
	 * Used to extract and return the extension of a given file.
	 * @param f Incoming file to get the extension of
	 * @return String representing the extension of the incoming
	 * file.
	 */
	 public static String getExtension(String f) {
	 String ext = "";
	 int i = f.lastIndexOf('.');

	 if (i > 0 && i < f.length() - 1) {
	 ext = f.substring(i+1);
	 }
	 return ext;
	 }

	 /**
	 * Used to extract the filename without its extension.
	 * @param f Incoming file to get the filename
	 * @return String representing the filename without its
	 * extension.
	 */
	 public static String getFileName(String f) {
	 String fname = "";
	 int i = f.lastIndexOf('.');

	 if (i > 0 && i < f.length() - 1) {
	 fname = f.substring(0,i);
	 }
	 return fname;
	 }

	 /**
	 * Sole entry point to the class and application.
	 * @param args Array of String arguments.
	 */
	 public static void main(String[] args) {

	 if (args.length != 1) {
	 System.err.println("Usage: java UncompressFileGZIP gzipfile");
	 } else {
	 doUncompressFile(args[0]);
	 }

	 }

	}
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　GZIP　　　　压缩　　解压缩　
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