c#对dataset和list集合压缩和解压，能提高访问速度
public class YS
{
public static byte[] Decompress(byte[] data)
{
byte[] bData;
MemoryStream ms = new MemoryStream();
//把数据写入到内存流
ms.Write(data, 0, data.Length);
//确定写入的位置，因为不是一次性写入
ms.Position = 0;
//解压流
GZipStream stream = new GZipStream(ms, CompressionMode.Decompress, true);
//性能处理
byte[] buffer = new byte[4096];
//临时内存流
MemoryStream temp = new MemoryStream();
//读入指定的文件流,0表示有没有到文件末尾
int read = stream.Read(buffer, 0, buffer.Length);
while (read > 0)
{
//写入到临时缓冲区内
temp.Write(buffer, 0, read);
//
read = stream.Read(buffer, 0, buffer.Length);
}
//必须把stream流关闭才能返回ms流数据,不然数据会不完整
stream.Close();
stream.Dispose();
ms.Close();
ms.Dispose();
bData = temp.ToArray();
temp.Close();
temp.Dispose();
return bData;
}
/// <summary>
/// 压缩数据
/// </summary>
/// <param name="data"></param>
/// <returns></returns>
public static byte[] Compress(byte[] data)
{
byte[] bData;
//创建内存流
MemoryStream ms = new MemoryStream();
//创建压缩解压对象
GZipStream stream = new GZipStream(ms, CompressionMode.Compress, true);
//把数据写入缓冲区
stream.Write(data, 0, data.Length);
stream.Close();
stream.Dispose();
//必须把stream流关闭才能返回ms流数据,不然数据会不完整
//并且解压缩方法stream.Read(buffer, 0, buffer.Length)时会返回0
bData = ms.ToArray();
ms.Close();
ms.Dispose();
return bData;
}
public static DataSet ConvertByteArrayToDataSet(Byte[] aByte)
{
DataSet resultDs = null;
MemoryStream ms = new MemoryStream(aByte);
IFormatter bf = new BinaryFormatter();
try
{
object obj = bf.Deserialize(ms);
resultDs = (DataSet)obj;
ms.Close();
return resultDs;
}
catch (Exception ex)
{
throw ex;
}
finally
{
if (ms != null) ms.Close();
resultDs.Dispose();
}
}
/// <summary>
/// 将DataSet格式化成字节数组byte[]
/// </summary>
/// <param name="dsOriginal">DataSet对象</param>
/// <returns>字节数组</returns>
public static Byte[] ConvertDataSetToByteArray(DataSet aDs)
{
//保存序列化的对象
Byte[] tranData;
//创建内存流
MemoryStream ms = new MemoryStream();
//创建格式化对象
IFormatter bf = new BinaryFormatter();
try
{
if (aDs == null) return null;
//设置序列化的方式
aDs.RemotingFormat = SerializationFormat.Binary;
//序列化字节对象
bf.Serialize(ms, aDs);
//把流转换成字节数组
tranData = ms.ToArray();
ms.Close();
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
finally
{
if (ms != null) ms.Close();
}
return tranData;
}
/// <summary>
/// 把list转换成dataset
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="list"></param>
/// <returns></returns>
public static DataSet ConvertToDataSet<T>(IList<T> list)
{
if (list == null || list.Count <= 0)
{
return null;
}
//创建dataset 对象
DataSet ds = new DataSet();
//创建表的，并且以类型的名字命名
DataTable dt = new DataTable(typeof(T).Name);
DataColumn column;
DataRow row;
//通过反射得到属性对象，只能得到简单的属性
System.Reflection.PropertyInfo[] myPropertyInfo
= typeof(T).GetProperties(System.Reflection.BindingFlags.Public
| System.Reflection.BindingFlags.Instance);
//遍历集合，遍历一次创建一行
foreach (T t in list)
{
if (t == null)
{
continue;
}
row = dt.NewRow();
//根据属性创建列
for (int i = 0, j = myPropertyInfo.Length; i < j; i++)
{
System.Reflection.PropertyInfo pi = myPropertyInfo[i];
string name = pi.Name;
if (name.Trim().ToLower().Equals("lastmodify"))
{
continue;
}
//判断列的值为不为空
if (dt.Columns[name] == null)
{
//获得属性的类型，作为列的类型
Type colType = pi.PropertyType;
//感觉这个if语句没啥用，有知道的朋友给我留言，谢谢了
if ((colType.IsGenericType) && (colType.GetGenericTypeDefinition()
== typeof(Nullable<>)))
{
colType = colType.GetGenericArguments()[0];
}
column = new DataColumn(name, colType);
dt.Columns.Add(column);
}
//获得属性的值，判断是不是为空
row[name] = pi.GetValue(t, null) == null ? DBNull.Value
: pi.GetValue(t, null);
}
dt.Rows.Add(row);
}
ds.Tables.Add(dt);
return ds;
}
public static List<T> GetList<T>(DataSet ds )
{
DataTable table = ds.Tables[0];
List<T> list = new List<T>();
//
T t = default(T);
PropertyInfo[] propertypes = null;
string tempName = string.Empty;
try
{
foreach (DataRow row in table.Rows)
{
//动态创建一个对象
t = Activator.CreateInstance<T>();
//获得该类的所有属性
propertypes = t.GetType().GetProperties();
//遍历属性
foreach (PropertyInfo pro in propertypes)
{
//属性名
tempName = pro.Name;
//检查表中是否包含该列
if (table.Columns.Contains(tempName))
{
object value = row[tempName];
//值不能为空，
if (value != null && value != DBNull.Value && row[tempName].ToString() != null &&
!row[tempName].ToString().Trim().Equals(""))
{
if (tempName.Trim().ToLower().Equals("lastmodify"))
{
// pro.SetValue(t, ConvertHelper.ConvertToTimestamp(Convert.ToString(value)), null);
}
else
{
//char类型单独处理
if (pro.PropertyType == typeof(System.Char)
|| pro.PropertyType == typeof(System.Nullable<System.Char>))
{
pro.SetValue(t, Convert.ToChar(value), null);
}
else
{
pro.SetValue(t, value, null);
}
}
}
//if (value.GetType() == typeof(System.DBNull))
//{
// value = null;
//}
//if (tempName.Trim().Equals("lastmodify"))
//{
// pro.SetValue(t,Convert.to
//pro.SetValue(t, 0, null);
//}
//else
//{
// pro.SetValue(t, value, null);
//}
}
}
list.Add(t);
}
}
catch (Exception ex)
{
throw new Exception(ex.Message);
}
return list;
}
}
static void Main(string[] args)
{
// using (BookShop2Entities context = new BookShop2Entities()) {
List<User<string>> list = new List<User<string>>{
new User<string>(){Age=90}
};
//把list集合转化成dataset
DataSet ds = YS.ConvertToDataSet(list);
//压缩dataset
byte[] byes =YS.ConvertDataSetToByteArray(ds);
Console.WriteLine("压缩之前字节数"+byes.Length);
byte[] byesYS =YS.Compress(byes);
Console.WriteLine("压缩之后字节数" + byesYS.Length);
byte[] byesJZ = YS.Decompress(byesYS);
Console.WriteLine("解压之后字节数" + byesJZ.Length);
//解压成dataset
DataSet ds2 = YS.ConvertByteArrayToDataSet(byesJZ);
//
Console.WriteLine("完成");
Console.Read();
}
这个自己写的，有什么问题可以给我留言
posted on 2014-09-23 16:54 topguntopgun 阅读(752) 评论(0) 编辑 收藏 举报
