C#实现压缩和解压缩的方法示例【Gzip和Zip方式】

本文实例讲述了c#实现压缩和解压缩的方法。分享给大家供大家参考，具体如下：

使用icsharpcode.sharpziplib.dll来压缩/解压（压缩效率比gzip要高一点）

public static class ziputil
{
    /// <summary>
    /// 压缩
    /// </summary>
    /// <param name="param"></param>
    /// <returns></returns>
    public static string compress(string param)
    {
      byte[] data = system.text.encoding.utf8.getbytes(param);
      //byte[] data = convert.frombase64string(param);
      memorystream ms = new memorystream();
      stream stream = new icsharpcode.sharpziplib.bzip2.bzip2outputstream(ms);
      try
      {
        stream.write(data, 0, data.length);
      }
      finally
      {
        stream.close();
        ms.close();
      }
      return convert.tobase64string(ms.toarray());
    }
    /// <summary>
    /// 解压
    /// </summary>
    /// <param name="param"></param>
    /// <returns></returns>
    public static string decompress(string param)
    {
      string commonstring = "";
      byte[] buffer = convert.frombase64string(param);
      memorystream ms = new memorystream(buffer);
      stream sm = new icsharpcode.sharpziplib.bzip2.bzip2inputstream(ms);
      //这里要指明要读入的格式，要不就有乱码
      streamreader reader = new streamreader(sm, system.text.encoding.utf8);
      try
      {
        commonstring = reader.readtoend();
      }
      finally
      {
        sm.close();
        ms.close();
      }
      return commonstring;
    }
}

使用gzip来压缩/解压缩（字符串）

public static class gziputil
{
    public static string zip(string value)
    {
      //transform string into byte[]
      byte[] bytearray = new byte[value.length];
      int indexba = 0;
      foreach (char item in value.tochararray())
      {
        bytearray[indexba++] = (byte)item;
      }
      //prepare for compress
      system.io.memorystream ms = new system.io.memorystream();
      system.io.compression.gzipstream sw = new system.io.compression.gzipstream(ms,
        system.io.compression.compressionmode.compress);
      //compress
      sw.write(bytearray, 0, bytearray.length);
      //close, do not flush cause bytes will go missing...
      sw.close();
      //transform byte[] zip data to string
      bytearray = ms.toarray();
      system.text.stringbuilder sb = new system.text.stringbuilder(bytearray.length);
      foreach (byte item in bytearray)
      {
        sb.append((char)item);
      }
      ms.close();
      sw.dispose();
      ms.dispose();
      return sb.tostring();
    }
    public static string unzip(string value)
    {
      //transform string into byte[]
      byte[] bytearray = new byte[value.length];
      int indexba = 0;
      foreach (char item in value.tochararray())
      {
        bytearray[indexba++] = (byte)item;
      }
      //prepare for decompress
      system.io.memorystream ms = new system.io.memorystream(bytearray);
      system.io.compression.gzipstream sr = new system.io.compression.gzipstream(ms,
        system.io.compression.compressionmode.decompress);
      //reset variable to collect uncompressed result
      bytearray = new byte[bytearray.length];
      //decompress
      int rbyte = sr.read(bytearray, 0, bytearray.length);
      //transform byte[] unzip data to string
      system.text.stringbuilder sb = new system.text.stringbuilder(rbyte);
      //read the number of bytes gzipstream red and do not a for each bytes in
      //resultbytearray;
      for (int i = 0; i < rbyte; i++)
      {
        sb.append((char)bytearray[i]);
      }
      sr.close();
      ms.close();
      sr.dispose();
      ms.dispose();
      return sb.tostring();
    }
}

更多关于c#相关内容感兴趣的读者可查看本站专题：《c#常见控件用法教程》、《winform控件用法总结》、《c#数据结构与算法教程》、《c#面向对象程序设计入门教程》及《c#程序设计之线程使用技巧总结》

希望本文所述对大家c#程序设计有所帮助。