java中GZIP压缩解压类使用实例

importjava.io.ByteArrayInputStream;

importjava.io.ByteArrayOutputStream;

importjava.io.IOException;

importjava.util.zip.GZIPInputStream;

importjava.util.zip.GZIPOutputStream;

/**

 * GZIP压缩解压类

 */

publicclassMessageGZIP {

  privatestaticString encode ="utf-8";//"ISO-8859-1"

  publicString getEncode() {

    returnencode;

  }

  /*

   * 设置 编码，默认编码：UTF-8

   */

  public void setEncode(String encode) {

    MessageGZIP.encode = encode;

  }

  /*

   * 字符串压缩为字节数组

   */

  public static byte[] compressToByte(String str){

    if (str == null || str.length() == 0) {

      return null;

    }

    ByteArrayOutputStream out = new ByteArrayOutputStream();

    GZIPOutputStream gzip;

    try {

      gzip = new GZIPOutputStream(out);

      gzip.write(str.getBytes(encode));

      gzip.close();

    } catch (IOException e) {

      e.printStackTrace();

    }

    return out.toByteArray();

  }

  /*

   * 字符串压缩为字节数组

   */

  public static byte[] compressToByte(String str,String encoding){

    if (str == null || str.length() == 0) {

      return null;

    }

    ByteArrayOutputStream out = new ByteArrayOutputStream();

    GZIPOutputStream gzip;

    try {

      gzip = new GZIPOutputStream(out);

      gzip.write(str.getBytes(encoding));

      gzip.close();

    } catch (IOException e) {

      e.printStackTrace();

    }

    return out.toByteArray();

  }

  /*

   * 字节数组解压缩后返回字符串

   */

  public static String uncompressToString(byte[] b) {

    if (b == null || b.length == 0) {

      return null;

    }

    ByteArrayOutputStream out = new ByteArrayOutputStream();

    ByteArrayInputStream in = new ByteArrayInputStream(b);

    try {

      GZIPInputStream gunzip = new GZIPInputStream(in);

      byte[] buffer = new byte[256];

      int n;

      while ((n = gunzip.read(buffer)) >= 0) {

        out.write(buffer, 0, n);

      }

    } catch (IOException e) {

      e.printStackTrace();

    }

    return out.toString();

  }

  /*

   * 字节数组解压缩后返回字符串

   */

  publicstaticString uncompressToString(byte[] b, String encoding) {

    if(b ==null|| b.length ==0) {

      returnnull;

    }

    ByteArrayOutputStream out =newByteArrayOutputStream();

    ByteArrayInputStream in =newByteArrayInputStream(b);

    try{

      GZIPInputStream gunzip =newGZIPInputStream(in);

      byte[] buffer =newbyte[256];

      intn;

      while((n = gunzip.read(buffer)) >=0) {

        out.write(buffer,0, n);

      }

      returnout.toString(encoding);

    }catch(IOException e) {

      e.printStackTrace();

    }

    returnnull;

  }

}