Apache在Commons Compress簡介和簡單應用

Apache在CommonsCompress中提供了眾所周知的tar、cpio、zip等壓縮算法實現，其中最為豐富的當屬zip實現了！

Commons Compress為壓縮（GZip和BZip2）構建了壓縮算法工廠類CompressorStreamFactory。通過這個類可以方便的構建GZip和BZip2的輸入輸出流，關鍵字分別為“gz”和“bzip2”。 
GZip 

Java代碼 

//GzipCompressorInputStream       

    CompressorInputStream gzipIn = newCompressorStreamFactory() 

            .createCompressorInputStream("gz",is); 



    // GzipCompressorOutputStream 

    CompressorOutputStream gzipOut = newCompressorStreamFactory() 

           .createCompressorOutputStream("gz", os);



BZip2 

Java代碼 

// BZip2CompressorInputStream 

    CompressorInputStream bzip2In =new CompressorStreamFactory() 

           .createCompressorInputStream("bzip2", is); 



    //BZip2CompressorOutputStream 

    CompressorOutputStream bzip2Out= new CompressorStreamFactory() 

           .createCompressorOutputStream("bzip2", os); 



下面是一個完整的通過apachecommons compress簡單實現bzip2壓縮的樣例。

需要導入的包為：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;

/* 通過apache commons compress簡單實現bzip2壓縮

 * 部分代碼來自互聯網

 * @author 范芳銘

 * */

publicclass BZip2Utils {

    public static final int BUFFER = 1024; 

    public static final CharSequence EXT =".bz2"; 



    /**

     * 數據壓縮

     * 

     * @param data

     * @return

     * @throws Exception

     */ 

    public static byte[] compress(byte[] data)throws Exception { 

        ByteArrayInputStream bais = newByteArrayInputStream(data); 

        ByteArrayOutputStream baos = newByteArrayOutputStream(); 



        // 壓縮 

        compress(bais, baos); 



        byte[] output =baos.toByteArray(); 



        baos.flush(); 

        baos.close(); 



        bais.close(); 



        return output; 

    } 



    /**

     * 文件壓縮

     * 

     * @param file

     * @param delete

     *            是否刪除原始文件

     * @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(); 

        } 

    } 



    /**

     * 數據壓縮

     * 

     * @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(); 

    } 



    /**

     * 文件壓縮

     * 

     * @param path

     * @param delete

     *            是否刪除原始文件

     * @throws Exception

     */ 

    public static void compress(String path,boolean delete) throws Exception { 

        File file = new File(path); 

        compress(file, delete); 

    } 



    /**

     * 數據解壓縮

     * 

     * @param data

     * @return

     * @throws Exception

     */ 

    public static byte[] decompress(byte[]data) throws Exception { 

        ByteArrayInputStream bais = newByteArrayInputStream(data); 

        ByteArrayOutputStream baos = newByteArrayOutputStream(); 



        // 解壓縮 



        decompress(bais, baos); 



        data = baos.toByteArray(); 



        baos.flush(); 

        baos.close(); 



        bais.close(); 



        return data; 

    } 



    /**

     * 文件解壓縮

     * 

     * @param file

     * @param delete

     *            是否刪除原始文件

     * @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(); 

        } 

    } 



    /**

     * 數據解壓縮

     * 

     * @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(); 

    } 



    /**

     * 文件解壓縮

     * 

     * @param path

     * @param delete

     *            是否刪除原始文件

     * @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("長度:\t" + input.length); 



        byte[] data = compress(input); 

        System.err.println("壓縮后:\t"); 

        System.err.println("長度:\t" + data.length); 



        byte[] output =  decompress(data); 

        String outputStr = newString(output); 

        System.err.println("解壓縮后:\t" + outputStr); 

        System.err.println("長度:\t" + output.length);

    }

}

運行結果如下：

原文:   http://blog.csdn.net/ffm83/article/details/42240513

長度:   51

壓縮后:

長度:   86

解壓縮后:   http://blog.csdn.net/ffm83/article/details/42240513

長度:   51