使用C#压缩/解压缩字符串
使用C#压缩/解压缩字符串
提问于 2011-09-08 13:27:04
我是.net的新手。我正在用C#做压缩和解压缩字符串。有一个XML，我正在转换成字符串，然后我做压缩，decompression.There在我的代码中没有编译错误，除非我解压缩我的代码并返回我的字符串，它只返回XML的一半。
下面是我的代码，请纠正我哪里错了。
代码：
class Program
{
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();
}
static void Main(string[] args)
{
XDocument doc = XDocument.Load(@"D:\RSP.xml");
string val = doc.ToString(SaveOptions.DisableFormatting);
val = Zip(val);
val = UnZip(val);
}
} 我的XML大小是63KB。
回答 4
Stack Overflow用户
发布于 2013-08-01 19:38:16
根据this snippet的说法，我使用了这段代码，它工作得很好：
using System;
using System.IO;
using System.IO.Compression;
using System.Text;
namespace CompressString
{
internal static class StringCompressor
{
/// <summary>
/// Compresses the string.
/// </summary>
/// <param name="text">The text.</param>
/// <returns></returns>
public static string CompressString(string text)
{
byte[] buffer = Encoding.UTF8.GetBytes(text);
var memoryStream = new MemoryStream();
using (var gZipStream = new GZipStream(memoryStream, CompressionMode.Compress, true))
{
gZipStream.Write(buffer, 0, buffer.Length);
}
memoryStream.Position = 0;
var compressedData = new byte[memoryStream.Length];
memoryStream.Read(compressedData, 0, compressedData.Length);
var gZipBuffer = new byte[compressedData.Length + 4];
Buffer.BlockCopy(compressedData, 0, gZipBuffer, 4, compressedData.Length);
Buffer.BlockCopy(BitConverter.GetBytes(buffer.Length), 0, gZipBuffer, 0, 4);
return Convert.ToBase64String(gZipBuffer);
}
/// <summary>
/// Decompresses the string.
/// </summary>
/// <param name="compressedText">The compressed text.</param>
/// <returns></returns>
public static string DecompressString(string compressedText)
{
byte[] gZipBuffer = Convert.FromBase64String(compressedText);
using (var memoryStream = new MemoryStream())
{
int dataLength = BitConverter.ToInt32(gZipBuffer, 0);
memoryStream.Write(gZipBuffer, 4, gZipBuffer.Length - 4);
var buffer = new byte[dataLength];
memoryStream.Position = 0;
using (var gZipStream = new GZipStream(memoryStream, CompressionMode.Decompress))
{
gZipStream.Read(buffer, 0, buffer.Length);
}
return Encoding.UTF8.GetString(buffer);
}
}
}
}Stack Overflow用户
发布于 2017-04-12 06:39:38
随着带有Stream.CopyTo()方法的.NET 4.0 (以及更高版本)的出现，我想我应该发布一种更新的方法。
我还认为下面的版本是一个很好的例子，它是一个自包含的类，用于将常规字符串压缩为Base64编码的字符串，反之亦然：
public static class StringCompression
{
/// <summary>
/// Compresses a string and returns a deflate compressed, Base64 encoded string.
/// </summary>
/// <param name="uncompressedString">String to compress</param>
public static string Compress(string uncompressedString)
{
byte[] compressedBytes;
using (var uncompressedStream = new MemoryStream(Encoding.UTF8.GetBytes(uncompressedString)))
{
using (var compressedStream = new MemoryStream())
{
// setting the leaveOpen parameter to true to ensure that compressedStream will not be closed when compressorStream is disposed
// this allows compressorStream to close and flush its buffers to compressedStream and guarantees that compressedStream.ToArray() can be called afterward
// although MSDN documentation states that ToArray() can be called on a closed MemoryStream, I don't want to rely on that very odd behavior should it ever change
using (var compressorStream = new DeflateStream(compressedStream, CompressionLevel.Fastest, true))
{
uncompressedStream.CopyTo(compressorStream);
}
// call compressedStream.ToArray() after the enclosing DeflateStream has closed and flushed its buffer to compressedStream
compressedBytes = compressedStream.ToArray();
}
}
return Convert.ToBase64String(compressedBytes);
}
/// <summary>
/// Decompresses a deflate compressed, Base64 encoded string and returns an uncompressed string.
/// </summary>
/// <param name="compressedString">String to decompress.</param>
public static string Decompress(string compressedString)
{
byte[] decompressedBytes;
var compressedStream = new MemoryStream(Convert.FromBase64String(compressedString));
using (var decompressorStream = new DeflateStream(compressedStream, CompressionMode.Decompress))
{
using (var decompressedStream = new MemoryStream())
{
decompressorStream.CopyTo(decompressedStream);
decompressedBytes = decompressedStream.ToArray();
}
}
return Encoding.UTF8.GetString(decompressedBytes);
}这里是使用扩展方法技术扩展String类以添加字符串压缩和解压缩的另一种方法。您可以将下面的类拖放到现有项目中，然后使用：
var uncompressedString = "Hello World!";
var compressedString = uncompressedString.Compress();和
var decompressedString = compressedString.Decompress();也就是说：
public static class Extensions
{
/// <summary>
/// Compresses a string and returns a deflate compressed, Base64 encoded string.
/// </summary>
/// <param name="uncompressedString">String to compress</param>
public static string Compress(this string uncompressedString)
{
byte[] compressedBytes;
using (var uncompressedStream = new MemoryStream(Encoding.UTF8.GetBytes(uncompressedString)))
{
using (var compressedStream = new MemoryStream())
{
// setting the leaveOpen parameter to true to ensure that compressedStream will not be closed when compressorStream is disposed
// this allows compressorStream to close and flush its buffers to compressedStream and guarantees that compressedStream.ToArray() can be called afterward
// although MSDN documentation states that ToArray() can be called on a closed MemoryStream, I don't want to rely on that very odd behavior should it ever change
using (var compressorStream = new DeflateStream(compressedStream, CompressionLevel.Fastest, true))
{
uncompressedStream.CopyTo(compressorStream);
}
// call compressedStream.ToArray() after the enclosing DeflateStream has closed and flushed its buffer to compressedStream
compressedBytes = compressedStream.ToArray();
}
}
return Convert.ToBase64String(compressedBytes);
}
/// <summary>
/// Decompresses a deflate compressed, Base64 encoded string and returns an uncompressed string.
/// </summary>
/// <param name="compressedString">String to decompress.</param>
public static string Decompress(this string compressedString)
{
byte[] decompressedBytes;
var compressedStream = new MemoryStream(Convert.FromBase64String(compressedString));
using (var decompressorStream = new DeflateStream(compressedStream, CompressionMode.Decompress))
{
using (var decompressedStream = new MemoryStream())
{
decompressorStream.CopyTo(decompressedStream);
decompressedBytes = decompressedStream.ToArray();
}
}
return Encoding.UTF8.GetString(decompressedBytes);
}Stack Overflow用户
发布于 2020-10-29 06:22:29
我最喜欢@fubo的答案，但我认为这个更优雅。
这种方法更兼容，因为它不会预先手动存储长度。
此外，我还公开了一些扩展，以支持从string到string、从byte[]到byte[]和从Stream到Stream的压缩。
public static class ZipExtensions
{
public static string CompressToBase64(this string data)
{
return Convert.ToBase64String(Encoding.UTF8.GetBytes(data).Compress());
}
public static string DecompressFromBase64(this string data)
{
return Encoding.UTF8.GetString(Convert.FromBase64String(data).Decompress());
}
public static byte[] Compress(this byte[] data)
{
using (var sourceStream = new MemoryStream(data))
using (var destinationStream = new MemoryStream())
{
sourceStream.CompressTo(destinationStream);
return destinationStream.ToArray();
}
}
public static byte[] Decompress(this byte[] data)
{
using (var sourceStream = new MemoryStream(data))
using (var destinationStream = new MemoryStream())
{
sourceStream.DecompressTo(destinationStream);
return destinationStream.ToArray();
}
}
public static void CompressTo(this Stream stream, Stream outputStream)
{
using (var gZipStream = new GZipStream(outputStream, CompressionMode.Compress))
{
stream.CopyTo(gZipStream);
gZipStream.Flush();
}
}
public static void DecompressTo(this Stream stream, Stream outputStream)
{
using (var gZipStream = new GZipStream(stream, CompressionMode.Decompress))
{
gZipStream.CopyTo(outputStream);
}
}
}页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/7343465
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