net core体系-web应用程序-4asp.net core2.0 项目实战（1）-10项目各种全局帮助类
本文目录
1. 前沿
2.CacheHelper基于Microsoft.Extensions.Caching.Memory封装
3.XmlHelper快速操作xml文档
4.SerializationHelper文件序列化操作
5.JsonHelper基于Newtonsoft.Json封装
6.ByteConvertHelper byte转换操作类
7. 总结
1. 前沿
Net Core2.0以前缓存操作、XML操作文档、处理JSON、序列化等都整理过相关帮助类，方便项目全局开发调用，但这些Helper在Net Core下面需要做调整才能使用，下面是我开发过程中整理的几个帮助类，可单独使用，仅供参考。
2. CacheHelper基于Microsoft.Extensions.Caching.Memory封装
在net core2.0下System.Web.Caching不在提供支持，取而代之的是Microsoft.Extensions.Caching.Memory，现在就基于新的类库做扩展封装。注意：netcore2.0文件依赖缓存好像没有扩展，修改文件信息后缓存自动更新功能暂未整合。
using System;
//using System.Web.Caching;//netcore2.0不再提供支持
using Microsoft.Extensions.Caching.Memory;
namespace NC.Common
{
/// <summary>
/// 为当前 HTTP 请求获取 Cache 对象。
/// </summary>
public class CacheHelper
{
static MemoryCache cache = new MemoryCache(new MemoryCacheOptions());
/// <summary>
/// 创建缓存项的文件
/// </summary>
/// <param name="key">缓存Key</param>
/// <param name="obj">object对象</param>
public static void Set(string key, object value)
{
if (key != null)
{
cache.Set(key, value);
}
}
/// <summary>
/// 创建缓存项过期
/// </summary>
/// <param name="key">缓存Key</param>
/// <param name="obj">object对象</param>
/// <param name="expires">过期时间(秒)</param>
public static void Set(string key, object value, int expires)
{
if (key != null)
{
cache.Set(key, value, new MemoryCacheEntryOptions()
//设置缓存时间，如果被访问重置缓存时间。设置相对过期时间x秒
.SetSlidingExpiration(TimeSpan.FromSeconds(expires)));
}
}
//dotnetcore2.0 文件依赖缓存好像没有，暂未找到。
///// <summary>
///// 创建缓存项的文件依赖
///// </summary>
///// <param name="key">缓存Key</param>
///// <param name="obj">object对象</param>
///// <param name="fileName">文件绝对路径</param>
//public static void Set(string key, object obj, string fileName)
//{
// //创建缓存依赖项
// CacheDependency dep = new CacheDependency(fileName);
// //创建缓存
// HttpContext.Current.Cache.Insert(key, obj, dep);
//}
/// <summary>
/// 获取缓存对象
/// </summary>
/// <param name="key">缓存Key</param>
/// <returns>object对象</returns>
public static object Get(string key)
{
object val = null;
if (key != null && cache.TryGetValue(key, out val))
{
return val;
}
else
{
return default(object);
}
}
/// <summary>
/// 获取缓存对象
/// </summary>
/// <typeparam name="T">T对象</typeparam>
/// <param name="key">缓存Key</param>
/// <returns></returns>
public static T Get<T>(string key)
{
object obj = Get(key);
return obj == null ? default(T) : (T)obj;
}
/// <summary>
/// 移除缓存项的文件
/// </summary>
/// <param name="key">缓存Key</param>
public static void Remove(string key)
{
cache.Remove(key);
}
}
}
3. XmlHelper快速操作xml文档
这里封装常见的对xml的操作和读取方法，追加节点，删除节点操作处理方法。配合序列化Hepler类处理。Core项目中实际使用过程中现仅用到SerializationHelper，里面序列化了xml并操作。由于xmlhelper做好了分享出来。
using System;
using System.Collections.Generic;
using System.Text;
using System.Xml;
namespace NC.Common
{
public class XmlHelper
{
#region --增、删、改操作--
/// <summary>
/// 追加节点
/// </summary>
/// <param name="filePath">XML文档绝对路径</param>
/// <param name="xPath">范例: @"Skill/First/SkillItem"</param>
/// <param name="xmlNode">XmlNode节点</param>
/// <returns></returns>
public static bool AppendChild(string filePath, string xPath, XmlNode xmlNode)
{
try
{
XmlDocument doc = new XmlDocument();
doc.Load(filePath);
XmlNode xn = doc.SelectSingleNode(xPath);
XmlNode n = doc.ImportNode(xmlNode, true);
xn.AppendChild(n);
doc.Save(filePath);
return true;
}
catch
{
return false;
}
}
/// <summary>
/// 从XML文档中读取节点追加到另一个XML文档中
/// </summary>
/// <param name="filePath">需要读取的XML文档绝对路径</param>
/// <param name="xPath">范例: @"Skill/First/SkillItem"</param>
/// <param name="toFilePath">被追加节点的XML文档绝对路径</param>
/// <param name="toXPath">范例: @"Skill/First/SkillItem"</param>
/// <returns></returns>
public static bool AppendChild(string filePath, string xPath, string toFilePath, string toXPath)
{
try
{
XmlDocument doc = new XmlDocument();
doc.Load(toFilePath);
XmlNode xn = doc.SelectSingleNode(toXPath);
XmlNodeList xnList = ReadNodes(filePath, xPath);
if (xnList != null)
{
foreach (XmlElement xe in xnList)
{
XmlNode n = doc.ImportNode(xe, true);
xn.AppendChild(n);
}
doc.Save(toFilePath);
}
return true;
}
catch
{
return false;
}
}
/// <summary>
/// 修改节点的InnerText的值
/// </summary>
/// <param name="filePath">XML文件绝对路径</param>
/// <param name="xPath">范例: @"Skill/First/SkillItem"</param>
/// <param name="value">节点的值</param>
/// <returns></returns>
public static bool UpdateNodeInnerText(string filePath, string xPath, string value)
{
try
{
XmlDocument doc = new XmlDocument();
doc.Load(filePath);
XmlNode xn = doc.SelectSingleNode(xPath);
XmlElement xe = (XmlElement)xn;
xe.InnerText = value;
doc.Save(filePath);
}
catch
{
return false;
}
return true;
}
/// <summary>
/// 读取XML文档
/// </summary>
/// <param name="filePath">XML文件绝对路径</param>
/// <returns></returns>
public static XmlDocument LoadXmlDoc(string filePath)
{
try
{
XmlDocument doc = new XmlDocument();
doc.Load(filePath);
return doc;
}
catch
{
return null;
}
}
#endregion 增、删、改操作
#region --读取XML的所有子节点--
/// <summary>
/// 读取XML的所有子节点
/// </summary>
/// <param name="filePath">XML文件绝对路径</param>
/// <param name="xPath">范例: @"Skill/First/SkillItem"</param>
/// <returns></returns>
public static XmlNodeList ReadNodes(string filePath, string xPath)
{
try
{
XmlDocument doc = new XmlDocument();
doc.Load(filePath);
XmlNode xn = doc.SelectSingleNode(xPath);
XmlNodeList xnList = xn.ChildNodes; //得到该节点的子节点
return xnList;
}
catch
{
return null;
}
}
#endregion 扩展方法
}
}
以上用的是try catch这种处理，如果使用using可以参考一下链接：https://www.cnblogs.com/Chary/p/No0000DE.html
4. SerializationHelper文件序列化操作
对xml文件进行序列化并操作，可以参考。
using System;
using System.Collections.Generic;
using System.IO;
using System.Text;
using System.Xml.Serialization;
namespace NC.Common
{
public class SerializationHelper
{
public SerializationHelper() { }
/// <summary>
/// 反序列化
/// </summary>
/// <param name="type">对象类型</param>
/// <param name="filename">文件路径</param>
/// <returns></returns>
public static object Load(Type type, string filename)
{
FileStream fs = null;
try
{
// open the stream...
fs = new FileStream(filename, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
XmlSerializer serializer = new XmlSerializer(type);
return serializer.Deserialize(fs);
}
catch (Exception ex)
{
throw ex;
}
finally
{
if (fs != null)
fs.Close();
}
}
/// <summary>
/// 序列化
/// </summary>
/// <param name="obj">对象</param>
/// <param name="filename">文件路径</param>
public static void Save(object obj, string filename)
{
FileStream fs = null;
// serialize it...
try
{
fs = new FileStream(filename, FileMode.Create, FileAccess.Write, FileShare.ReadWrite);
XmlSerializer serializer = new XmlSerializer(obj.GetType());
serializer.Serialize(fs, obj);
}
catch (Exception ex)
{
throw ex;
}
finally
{
if (fs != null)
fs.Close();
}
}
}
}
调用案例：
#region--站点配置文件--
/// <summary>
/// 读取配置文件
/// </summary>
public NC.Model.siteconfig loadConfig()
{
NC.Model.siteconfig model = CacheHelper.Get<NC.Model.siteconfig>(JHKeys.CACHE_SYS_CONFIG);
if (model == null)
{
//netcore2.0文件依赖缓存没有，暂时只能修改文件后手动清空一次缓存
//Utils.GetXmlMapPath(JHKeys.FILE_SYS_XML_CONFING);
//CacheHelper是NET Core下Microsoft.Extensions.Caching.Memory缓存帮助类
CacheHelper.Set(JHKeys.CACHE_SYS_CONFIG, (NC.Model.siteconfig)SerializationHelper.Load(typeof(NC.Model.siteconfig), Utils.GetXmlMapPath(JHKeys.FILE_SYS_XML_CONFING)));
model = CacheHelper.Get<NC.Model.siteconfig>(JHKeys.CACHE_SYS_CONFIG);
}
return model;
}
/// <summary>
/// 保存配置文件
/// </summary>
public NC.Model.siteconfig saveConifg(NC.Model.siteconfig model)
{
return saveConifg(model, Utils.GetXmlMapPath(JHKeys.FILE_SYS_XML_CONFING));
}
private static object lockHelper = new object();
/// <summary>
/// 写入站点配置文件
/// </summary>
public NC.Model.siteconfig saveConifg(NC.Model.siteconfig model, string configFilePath)
{
// 清缓存
CacheHelper.Remove(JHKeys.CACHE_SYS_CONFIG);
lock (lockHelper)
{
SerializationHelper.Save(model, configFilePath);
}
return model;
}
#endregion
5. JsonHelper基于Newtonsoft.Json封装
using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Data;
using System.Text;
namespace NC.Common
{
/// <summary>
/// JSON帮助类
/// </summary>
public class JsonHelper
{
/// <summary>
/// 对象转JSON
/// </summary>
/// <param name="obj">对象</param>
/// <returns>JSON格式的字符串</returns>
public static string ObjectToJSON(object obj)
{
try
{
byte[] b = Encoding.UTF8.GetBytes(JsonConvert.SerializeObject(obj));
return Encoding.UTF8.GetString(b);
}
catch (Exception ex)
{
throw new Exception("JSONHelper.ObjectToJSON(): " + ex.Message);
}
}
/// <summary>
/// 数据表转键值对集合
/// 把DataTable转成 List集合, 存每一行
/// 集合中放的是键值对字典,存每一列
/// </summary>
/// <param name="dt">数据表</param>
/// <returns>哈希表数组</returns>
public static List<Dictionary<string, object>> DataTableToList(DataTable dt)
{
List<Dictionary<string, object>> list
= new List<Dictionary<string, object>>();
foreach (DataRow dr in dt.Rows)
{
Dictionary<string, object> dic = new Dictionary<string, object>();
foreach (DataColumn dc in dt.Columns)
{
dic.Add(dc.ColumnName, dr[dc.ColumnName]);
}
list.Add(dic);
}
return list;
}
/// <summary>
/// 数据集转键值对数组字典
/// </summary>
/// <param name="dataSet">数据集</param>
/// <returns>键值对数组字典</returns>
public static Dictionary<string, List<Dictionary<string, object>>> DataSetToDic(DataSet ds)
{
Dictionary<string, List<Dictionary<string, object>>> result = new Dictionary<string, List<Dictionary<string, object>>>();
foreach (DataTable dt in ds.Tables)
result.Add(dt.TableName, DataTableToList(dt));
return result;
}
/// <summary>
/// 数据表转JSON
/// </summary>
/// <param name="dataTable">数据表</param>
/// <returns>JSON字符串</returns>
public static string DataTableToJSON(DataTable dt)
{
return ObjectToJSON(DataTableToList(dt));
}
/// <summary>
/// JSON文本转对象,泛型方法
/// </summary>
/// <typeparam name="T">类型</typeparam>
/// <param name="jsonText">JSON文本</param>
/// <returns>指定类型的对象</returns>
public static T JSONToObject<T>(string jsonText)
{
//JavaScriptSerializer jss = new JavaScriptSerializer();
try
{
return JsonConvert.DeserializeObject<T>(jsonText);
//return jss.Deserialize<T>(jsonText);
}
catch (Exception ex)
{
throw new Exception("JSONHelper.JSONToObject(): " + ex.Message);
}
}
/// <summary>
/// 将JSON文本转换为数据表数据
/// </summary>
/// <param name="jsonText">JSON文本</param>
/// <returns>数据表字典</returns>
public static Dictionary<string, List<Dictionary<string, object>>> TablesDataFromJSON(string jsonText)
{
return JSONToObject<Dictionary<string, List<Dictionary<string, object>>>>(jsonText);
}
/// <summary>
/// 将JSON文本转换成数据行
/// </summary>
/// <param name="jsonText">JSON文本</param>
/// <returns>数据行的字典</returns>
public static Dictionary<string, object> DataRowFromJSON(string jsonText)
{
return JSONToObject<Dictionary<string, object>>(jsonText);
}
}
}
6. ByteConvertHelper byte转换操作类
Byte转换操作类这里主要配合session存储使用，net core 2.0存储session 类型为object，先转成byte存储，读取再通过byte转object。
例如Session存储值是字符串；设置session：HttpContext.Session.SetString("name","hello world!"); 获取session：string str = HttpContext.Session.GetString("name");
using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Text;
namespace NC.Common
{
/// <summary>
/// byte转换操作类，主要用于Session存储
/// </summary>
public class ByteConvertHelper
{
/// <summary>
/// 将对象转换为byte数组
/// </summary>
/// <param name="obj">被转换对象</param>
/// <returns>转换后byte数组</returns>
public static byte[] Object2Bytes(object obj)
{
byte[] serializedResult = Encoding.UTF8.GetBytes(JsonConvert.SerializeObject(obj));
return serializedResult;
}
/// <summary>
/// 将byte数组转换成对象
/// </summary>
/// <param name="buff">被转换byte数组</param>
/// <returns>转换完成后的对象</returns>
public static object Bytes2Object(byte[] buff)
{
return JsonConvert.DeserializeObject<object>(Encoding.UTF8.GetString(buff));
}
/// <summary>
/// 将byte数组转换成对象
/// </summary>
/// <param name="buff">被转换byte数组</param>
/// <returns>转换完成后的对象</returns>
public static T Bytes2Object<T>(byte[] buff)
{
return JsonConvert.DeserializeObject<T>(Encoding.UTF8.GetString(buff));
}
}
}
调用实例参考《Asp.Net Core 2.0 项目实战（11） 基于OnActionExecuting全局过滤器，页面操作权限过滤控制到按钮级》中的<3.5 Session相关操作>。
7. 总结
以上帮助类只是为了快速开发，文中有些帮助类是由webform项目升级改造的，适合自己项目的一些封装，仅供参考。需要做成帮助类全局调用的Helper还有很多，欢迎大家多多交流，谢谢！
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