Apache在CommonsCompress中提供了众所周知的tar、cpio、zip等压缩算法实现，其中最为丰富的当属zip实现了！
Commons Compress为压缩（GZip和BZip2）构建了压缩算法工厂类CompressorStreamFactory。通过这个类可以方便的构建GZip和BZip2的输入输出流，关键字分别为“gz”和“bzip2”。
GZip
Java代码
//GzipCompressorInputStream
CompressorInputStream gzipIn = newCompressorStreamFactory()
.createCompressorInputStream("gz",is);
// GzipCompressorOutputStream
CompressorOutputStream gzipOut = newCompressorStreamFactory()
.createCompressorOutputStream("gz", os);
BZip2
Java代码
// BZip2CompressorInputStream
CompressorInputStream bzip2In =new CompressorStreamFactory()
.createCompressorInputStream("bzip2", is);
//BZip2CompressorOutputStream
CompressorOutputStream bzip2Out= new CompressorStreamFactory()
.createCompressorOutputStream("bzip2", os);
下面是一个完整的通过apachecommons compress简单实现bzip2压缩的样例。
需要导入的包为：commons-compress-1.9.jar
packagetest.ffm83.commons.compress;
importjava.io.ByteArrayInputStream;
importjava.io.ByteArrayOutputStream;
importjava.io.File;
importjava.io.FileInputStream;
importjava.io.FileOutputStream;
importjava.io.InputStream;
importjava.io.OutputStream;
importorg.apache.commons.compress.compressors.bzip2.BZip2CompressorInputStream;
importorg.apache.commons.compress.compressors.bzip2.BZip2CompressorOutputStream;
/* 通过apache commons compress简单实现bzip2压缩
* 部分代码来自互联网
* @author 范芳铭
* */
publicclass BZip2Utils {
public static final int BUFFER = 1024;
public static final CharSequence EXT =".bz2";
/**
* 数据压缩
*
* @param data
* @return
* @throws Exception
*/
public static byte[] compress(byte[] data)throws Exception {
ByteArrayInputStream bais = newByteArrayInputStream(data);
ByteArrayOutputStream baos = newByteArrayOutputStream();
// 压缩
compress(bais, baos);
byte[] output =baos.toByteArray();
baos.flush();
baos.close();
bais.close();
return output;
}
/**
* 文件压缩
*
* @param file
* @param delete
* 是否删除原始文件
* @throws Exception
*/
public static void compress(File file,boolean delete) throws Exception {
FileInputStream fis = newFileInputStream(file);
FileOutputStream fos = newFileOutputStream(file.getPath() + EXT);
compress(fis, fos);
fis.close();
fos.flush();
fos.close();
if (delete) {
file.delete();
}
}
/**
* 数据压缩
*
* @param is
* @param os
* @throws Exception
*/
public static void compress(InputStream is,OutputStream os)
throws Exception {
BZip2CompressorOutputStream gos = newBZip2CompressorOutputStream(os);
int count;
byte data[] = new byte[BUFFER];
while ((count = is.read(data, 0, BUFFER)) !=-1) {
gos.write(data, 0, count);
}
gos.finish();
gos.flush();
gos.close();
}
/**
* 文件压缩
*
* @param path
* @param delete
* 是否删除原始文件
* @throws Exception
*/
public static void compress(String path,boolean delete) throws Exception {
File file = new File(path);
compress(file, delete);
}
/**
* 数据解压缩
*
* @param data
* @return
* @throws Exception
*/
public static byte[] decompress(byte[]data) throws Exception {
ByteArrayInputStream bais = newByteArrayInputStream(data);
ByteArrayOutputStream baos = newByteArrayOutputStream();
// 解压缩
decompress(bais, baos);
data = baos.toByteArray();
baos.flush();
baos.close();
bais.close();
return data;
}
/**
* 文件解压缩
*
* @param file
* @param delete
* 是否删除原始文件
* @throws Exception
*/
public static void decompress(File file,boolean delete) throws Exception {
FileInputStream fis = newFileInputStream(file);
FileOutputStream fos = newFileOutputStream(file.getPath().replace(EXT,
""));
decompress(fis, fos);
fis.close();
fos.flush();
fos.close();
if (delete) {
file.delete();
}
}
/**
* 数据解压缩
*
* @param is
* @param os
* @throws Exception
*/
public static void decompress(InputStreamis, OutputStream os)
throws Exception {
BZip2CompressorInputStream gis = newBZip2CompressorInputStream(is);
int count;
byte data[] = new byte[BUFFER];
while ((count = gis.read(data, 0,BUFFER)) != -1) {
os.write(data, 0, count);
}
gis.close();
}
/**
* 文件解压缩
*
* @param path
* @param delete
* 是否删除原始文件
* @throws Exception
*/
public static void decompress(String path,boolean delete) throws Exception {
File file = new File(path);
decompress(file, delete);
}
public static void main(String[] args)throws Exception{
StringinputStr = "http://blog.csdn.net/ffm83/article/details/42240513";
byte[]input = inputStr.getBytes();
System.out.println("原文:\t" + inputStr);
System.out.println("长度:\t" + input.length);
byte[] data = compress(input);
System.err.println("压缩后:\t");
System.err.println("长度:\t" + data.length);
byte[] output = decompress(data);
String outputStr = newString(output);
System.err.println("解压缩后:\t" + outputStr);
System.err.println("长度:\t" + output.length);
}
}
运行结果如下：
原文: http://blog.csdn.net/ffm83/article/details/42240513
长度: 51
压缩后:
长度: 86
解压缩后: http://blog.csdn.net/ffm83/article/details/42240513
长度: 51