java 解析压缩文件-gzip

package impl;

import inter.AbstractUnCompressService;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.zip.GZIPInputStream;

import org.apache.tools.tar.TarEntry;
import org.apache.tools.tar.TarInputStream;

/**
 * This file is used to uncompress gz compress file
 * @author Jacky.Dong
 *
 */
public class GzUnCompressServiceImpl extends AbstractUnCompressService {

	private static final String SUFFIX_TAR_GZ = ".tar.gz";

	@Override
	public void unCompressFolder(String folder) {
		// TODO Auto-generated method stub

	}

	@Override
	public void unCompressFile(String inputFilePath, String outputDir)
			throws IOException {

		File inputFile = new File(inputFilePath);
		if (outputDir == null) {
			outputDir = inputFile.getPath().replace(SUFFIX_TAR_GZ, "")
					+ File.separator;
		}

		try {
			// create a gzip input stream
			TarInputStream tarIn = new TarInputStream(new GZIPInputStream(
					new FileInputStream(inputFile)));

			TarEntry entry = null;
			while ((entry = tarIn.getNextEntry()) != null) {
				// if entry is a directory ,we should create a new directory
				if (entry.isDirectory()) {
					createDirectory(outputDir, entry.getName());// 创建空目录
				} else {
					// if entry is a file ,we should add this file to related
					// folder and write content to the file
					File tmpFile = new File(outputDir + File.separator
							+ entry.getName());
					createDirectory(tmpFile.getParent() + File.separator, null);
					OutputStream out = null;

					try {
						out = new FileOutputStream(tmpFile);
						int length = 0;
						byte[] b = new byte[BUFFEREDSIZE];

						while ((length = tarIn.read(b)) != -1) {
							out.write(b, 0, length);
						}
					} catch (IOException ex) {
						throw ex;
					} finally {
						if (out != null)
							out.close();
					}

				}
			}
		} catch (Exception ex) {
			System.err.println(ex.toString());
		}
	}

}