C#使用GZipStream实现压缩和解压缩

前言

我们在项目中，有可能会遇到存入到数据库或者传输的数据量比较大，这个时候，就可以考虑在存入数据库或者发送传输之前，将数据压缩下，当从数据库中取出时，再解压还原数据。

正文

废话不多说，我封装了一个工具类用于压缩和解压数据，代码如下：

using System;
using System.IO;
using System.IO.Compression;
using System.Text;

namespace Test
{
    public class GZipUtils
    {
        /// <summary>
        /// 压缩指定字符串
        /// </summary>
        /// <param name="str">待压缩字符串</param>
        /// <returns>返回压缩后的字节数组</returns>
        public static byte[] Compress(string str)
        {
            if (string.IsNullOrEmpty(str)) return null;

            byte[] bytes = Encoding.UTF8.GetBytes(str);
            return Compress(bytes);
        }

        /// <summary>
        /// 压缩指定字节数组
        /// </summary>
        /// <param name="bytes">待压缩字节数组</param>
        /// <returns>返回压缩后的字节数组</returns>
        public static byte[] Compress(byte[] bytes)
        {
            if (bytes == null || bytes.Length <= 0) return bytes;

            using (var compressedStream = new MemoryStream())
            {
                using (var compressionStream = new GZipStream(compressedStream, CompressionMode.Compress))
                {
                    compressionStream.Write(bytes, 0, bytes.Length);
                }
                return compressedStream.ToArray();
            }
        }

        /// <summary>
        /// 压缩指定字符串到指定文件中
        /// </summary>
        /// <param name="compressData">待压缩字符串</param>
        /// <param name="zipFilePath">压缩后的文件路径</param>
        public static void CompressToFile(string compressData, string zipFilePath)
        {
            if (!string.IsNullOrEmpty(compressData))
            {
                byte[] bytes = Encoding.UTF8.GetBytes(compressData);
                using (var originalStream = new MemoryStream(bytes))
                {
                    using (FileStream compressedStream = File.Create(zipFilePath))
                    {
                        using (GZipStream compressionStream = new GZipStream(compressedStream, CompressionMode.Compress))
                        {
                            originalStream.CopyTo(compressionStream);
                        }
                    }
                }
            }
        }

        /// <summary>
        /// 从指定字节数组解压出字符串
        /// </summary>
        /// <param name="bytes">待解压的字节数组</param>
        /// <returns>返回解压后的字符串</returns>
        public static string DecompressToString(byte[] bytes)
        {
            var result = Decompress(bytes);
            if (result == null || result.Length <= 0) return string.Empty;

            return Encoding.UTF8.GetString(result);
        }

        /// <summary>
        /// 从指定字节数组解压出字节数组
        /// </summary>
        /// <param name="bytes">待解压的字节数组</param>
        /// <returns>返回解压后的字节数组</returns>
        public static byte[] Decompress(byte[] bytes)
        {
            if (bytes == null || bytes.Length <= 0) return bytes;

            using (var originalStream = new MemoryStream(bytes))
            {
                using (var decompressedStream = new MemoryStream())
                {
                    using (var decompressionStream = new GZipStream(originalStream, CompressionMode.Decompress))
                    {
                        decompressionStream.CopyTo(decompressedStream);
                    }
                    return decompressedStream.ToArray();
                }
            }
        }

        /// <summary>
        /// 从指定文件中解压出字符串
        /// </summary>
        /// <param name="zipFilePath">待解压的文件路径</param>
        /// <returns>返回解压后的字符串</returns>
        public static string DecompressFromFile(string zipFilePath)
        {
            if (File.Exists(zipFilePath))
            {
                using (FileStream originalStream = File.Open(zipFilePath, FileMode.Open))
                {
                    using (MemoryStream decompressedStream = new MemoryStream())
                    {
                        using (GZipStream decompressionStream = new GZipStream(originalStream, CompressionMode.Decompress))
                        {
                            decompressionStream.CopyTo(decompressedStream);
                        }
                        byte[] bytes = decompressedStream.ToArray();
                        return Encoding.UTF8.GetString(bytes);
                    }
                }
            }
            return string.Empty;
        }
    }
}

参考文档

1. C# 关于GZipStream压缩与解压缩数据丢失问题

2. GZipStream 类 (System.IO.Compression)