你的位置:首页 > ASP.net教程

[ASP.net教程]JSON扩展类——JsonHelper


1.引用Newtonsoft.Json库(JSON.NET)。

2.复制粘贴JsonHelper吧。

 

源代码:

using System;using System.Collections.Generic;using System.Linq;using Newtonsoft.Json;using Newtonsoft.Json.Converters;namespace Allen.Core{  public static partial class JsonHelper  {    #region Private fields    private static readonly JsonSerializerSettings JsonSettings;    private const string EmptyJson = "[]";    #endregion    #region Constructor    static JsonHelper()    {      var datetimeConverter = new IsoDateTimeConverter { DateTimeFormat = "yyyy-MM-dd HH:mm:ss" };      JsonSettings = new JsonSerializerSettings      {        MissingMemberHandling = MissingMemberHandling.Ignore,        NullValueHandling = NullValueHandling.Ignore,        ReferenceLoopHandling = ReferenceLoopHandling.Ignore      };      JsonSettings.Converters.Add(datetimeConverter);    }    #endregion    #region Public Methods    /// <summary>    /// 应用Formatting.None和指定的JsonSerializerSettings设置,序列化对象到JSON格式的字符串    /// </summary>    /// <param name="obj">任意一个对象</param>    /// <param name="jsonSettings">在一个 Newtonsoft.Json.JsonSerializer 对象上指定设置,如果为null,则使用默认设置</param>    /// <returns>标准的JSON格式的字符串</returns>    public static string ToJson(object obj, JsonSerializerSettings jsonSettings)    {      return ToJson(obj, Formatting.None, jsonSettings);    }    /// <summary>    /// 应用指定的Formatting枚举值None和指定的JsonSerializerSettings设置,序列化对象到JSON格式的字符串    /// </summary>    /// <param name="obj">任意一个对象</param>    /// <param name="format">指定 Newtonsoft.Json.JsonTextWriter 的格式设置选项</param>    /// <param name="jsonSettings">在一个 Newtonsoft.Json.JsonSerializer 对象上指定设置,如果为null,则使用默认设置</param>    /// <returns>标准的JSON格式的字符串</returns>    public static string ToJson(object obj, Formatting format, JsonSerializerSettings jsonSettings)    {      try      {        return obj == null ? EmptyJson : JsonConvert.SerializeObject(obj, format, jsonSettings ?? JsonSettings);      }      catch (Exception)      {        //TODO LOG        return EmptyJson;      }    }    /// <summary>    /// 应用Formatting.None和指定的JsonSerializerSettings设置,反序列化JSON数据为dynamic对象    /// <para>如果发生JsonSerializationException异常,再以集合的方式重试一次,取出集合的第一个dynamic对象。</para>    /// <para>转换失败,或发生其它异常,则返回dynamic对象的默认值</para>    /// </summary>    /// <param name="json">需要反序列化的JSON字符串</param>    /// <param name="jsonSettings">在一个 Newtonsoft.Json.JsonSerializer 对象上指定设置,如果为null,则使用默认设置</param>    /// <returns>dynamic对象</returns>    public static dynamic FromJson(this string json, JsonSerializerSettings jsonSettings)    {      return FromJson<dynamic>(json, Formatting.None, jsonSettings);    }    /// <summary>    /// 应用指定的Formatting枚举值None和指定的JsonSerializerSettings设置,反序列化JSON数据为dynamic对象    /// <para>如果发生JsonSerializationException异常,再以集合的方式重试一次,取出集合的第一个dynamic对象。</para>    /// <para>转换失败,或发生其它异常,则返回dynamic对象的默认值</para>    /// </summary>    /// <param name="json">需要反序列化的JSON字符串</param>    /// <param name="format">指定 Newtonsoft.Json.JsonTextWriter 的格式设置选项</param>    /// <param name="jsonSettings">在一个 Newtonsoft.Json.JsonSerializer 对象上指定设置,如果为null,则使用默认设置</param>    /// <returns>dynamic对象</returns>    public static dynamic FromJson(this string json, Formatting format, JsonSerializerSettings jsonSettings)    {      return FromJson<dynamic>(json, format, jsonSettings);    }    /// <summary>    /// 应用Formatting.None和指定的JsonSerializerSettings设置,反序列化JSON数据到指定的.NET类型对象    /// <para>如果发生JsonSerializationException异常,再以集合的方式重试一次,取出集合的第一个T对象。</para>    /// <para>转换失败,或发生其它异常,则返回T对象的默认值</para>    /// </summary>    /// <param name="json">需要反序列化的JSON字符串</param>    /// <param name="jsonSettings">在一个 Newtonsoft.Json.JsonSerializer 对象上指定设置,如果为null,则使用默认设置</param>    /// <typeparam name="T">反序列化对象的类型</typeparam>    /// <returns></returns>    public static T FromJson<T>(string json, JsonSerializerSettings jsonSettings) where T : class, new()    {      return FromJson<T>(json, Formatting.None, jsonSettings);    }    /// <summary>    /// 应用指定的Formatting枚举值None和指定的JsonSerializerSettings设置,反序列化JSON数据到指定的.NET类型对象    /// <para>如果发生JsonSerializationException异常,再以集合的方式重试一次,取出集合的第一个T对象。</para>    /// <para>转换失败,或发生其它异常,则返回T对象的默认值</para>    /// </summary>    /// <param name="json">需要反序列化的JSON字符串</param>    /// <param name="format">指定 Newtonsoft.Json.JsonTextWriter 的格式设置选项</param>    /// <param name="jsonSettings">在一个 Newtonsoft.Json.JsonSerializer 对象上指定设置,如果为null,则使用默认设置</param>    /// <typeparam name="T">反序列化对象的类型</typeparam>    /// <returns></returns>    public static T FromJson<T>(string json, Formatting format, JsonSerializerSettings jsonSettings) where T : class, new()    {      T result;      if (jsonSettings == null)      {        jsonSettings = JsonSettings;      }      try      {        result = string.IsNullOrWhiteSpace(json) ? default(T) : JsonConvert.DeserializeObject<T>(json, jsonSettings);      }      catch (JsonSerializationException) //在发生该异常后,再以集合的方式重试一次.      {        //LOG        try        {          var array = JsonConvert.DeserializeObject<IEnumerable<T>>(json, jsonSettings);          result = array.FirstOrDefault();        }        catch (Exception)        {          //LOG          result = default(T);        }      }      catch (Exception)      {        //LOG        result = default(T);      }      return result;    }    #endregion    #region Public Extend Methods    /// <summary>    /// 反序列化JSON数据为dynamic对象    /// <para>如果发生JsonSerializationException异常,再以集合的方式重试一次,取出集合的第一个dynamic对象。</para>    /// <para>转换失败,或发生其它异常,则返回dynamic对象的默认值</para>    /// </summary>    /// <param name="json">需要反序列化的JSON字符串</param>    /// <returns>dynamic对象</returns>    public static dynamic FromJson(this string json)    {      return FromJson<dynamic>(json, Formatting.None, JsonSettings);    }    /// <summary>    /// 反序列化JSON数据到指定的.NET类型对象    /// <para>如果发生JsonSerializationException异常,再以集合的方式重试一次,取出集合的第一个T对象。</para>    /// <para>转换失败,或发生其它异常,则返回T对象的默认值</para>    /// </summary>    /// <param name="json">需要反序列化的JSON字符串</param>    /// <typeparam name="T">反序列化对象的类型</typeparam>    /// <returns></returns>    public static T FromJson<T>(this string json) where T : class, new()    {      return FromJson<T>(json, Formatting.None, JsonSettings);    }    /// <summary>    /// 应用默认的Formatting枚举值None和默认的JsonSerializerSettings设置,序列化对象到JSON格式的字符串    /// </summary>    /// <param name="obj">任意一个对象</param>    /// <returns>标准的JSON格式的字符串</returns>    public static string ToJson(this object obj)    {      return ToJson(obj, Formatting.None, JsonSettings);    }    public static string ToJson<TSource>(this IEnumerable<TSource> source, Func<TSource, bool> predicate, bool isFilterNull = true)    {      return DelegateToJson(source, enumerable => enumerable.Where(predicate), isFilterNull);    }    public static string ToJson<TSource>(this IEnumerable<TSource> source, Func<TSource, int, bool> predicate, bool isFilterNull = true)    {      return DelegateToJson(source, enumerable => enumerable.Where(predicate), isFilterNull);    }    public static string ToJson<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, TResult> selector, bool isFilterNull = true)    {      return DelegateToJson(source, enumerable => enumerable.Where(t => t != null).Select(selector), isFilterNull);    }    public static string ToJson<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, int, TResult> selector, bool isFilterNull = true)    {      return DelegateToJson(source, enumerable => enumerable.Where(t => t != null).Select(selector), isFilterNull);    }    public static string ToJson<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, bool> predicate, Func<TSource, TResult> selector, bool isFilterNull = true)    {      return DelegateToJson(source, enumerable => enumerable.Where(predicate).Select(selector), isFilterNull);    }    public static string ToJson<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, bool> predicate, Func<TSource, int, TResult> selector, bool isFilterNull = true)    {      return DelegateToJson(source, enumerable => enumerable.Where(predicate).Select(selector), isFilterNull);    }    public static string ToJson<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, int, bool> predicate, Func<TSource, TResult> selector, bool isFilterNull = true)    {      return DelegateToJson(source, enumerable => enumerable.Where(predicate).Select(selector), isFilterNull);    }    public static string ToJson<TSource, TResult>(this IEnumerable<TSource> source, Func<TSource, int, bool> predicate, Func<TSource, int, TResult> selector, bool isFilterNull = true)    {      return DelegateToJson(source, enumerable => enumerable.Where(predicate).Select(selector), isFilterNull);    }    #endregion    #region Private Methods    /// <summary>    /// 委托处理需要序列化为JSON格式的对象,返回标准的JSON格式的字符串。    /// 默认过滤null对象,如果需要在上层调用时,自己进行条件过滤null对象,    /// 则设置isFilterNull为false,不建议isFilterNull设置为false。    /// </summary>    /// <typeparam name="TSource"></typeparam>    /// <typeparam name="TResult"></typeparam>    /// <param name="source">需要转换为JSON格式字符串的对象</param>    /// <param name="func">集合/数组条件筛选方法委托,返回筛选后的集合/数组</param>    /// <param name="isFilterNull">是否过滤IEnumerable<TSource> source中的null对象,默认为true</param>    /// <returns>标准的JSON格式的字符串</returns>    private static string DelegateToJson<TSource, TResult>(IEnumerable<TSource> source, Func<TSource[], IEnumerable<TResult>> func, bool isFilterNull = true)    {      return DelegateToJson(source, enumerable => func(enumerable).ToJson(), isFilterNull);    }    /// <summary>    /// 委托处理需要序列化为JSON格式的对象,返回标准的JSON格式的字符串。    /// 默认过滤null对象,如果需要在上层调用时,自己进行条件过滤null对象,    /// 则设置isFilterNull为false,不建议isFilterNull设置为false。    /// </summary>    /// <typeparam name="TSource"></typeparam>    /// <param name="source">需要转换为JSON格式字符串的对象</param>    /// <param name="func">JSON处理方法委托,返回JSON格式的字符串</param>    /// <param name="isFilterNull">是否过滤IEnumerable<TSource> source中的null对象,默认为true</param>    /// <returns>标准的JSON格式的字符串</returns>    private static string DelegateToJson<TSource>(IEnumerable<TSource> source, Func<TSource[], string> func, bool isFilterNull = true)    {      if (source == null)      {        return EmptyJson;      }      TSource[] enumerable;      if (isFilterNull)      {        //过滤null        enumerable = source.Where(t => t != null).ToArray();      }      else      {        //不过滤null,但上层需要注意内里面有null对象时,可能会导致Where或Select引发异常。        enumerable = source as TSource[] ?? source.ToArray();      }      return enumerable.Any() ? func(enumerable) : EmptyJson;    }    #endregion  }}

 

用法案例:

class Program  {    static void Main(string[] args)    {      //ToJson 方法 Test      #region 默认过滤null对象      var list1 = new List<Test>      {        new Test {Id = 10, Type = 21, Name="Allen"},        new Test {Id = 11, Type = 22},        new Test {Id = 12, Type = 23},        new Test {Id = 13, Type = 24, Name="Peter"},        null,        new Test {Id = 13, Type = 24, Name=null}      };      //指定json数据所需要的属性      string jsonString = list1.ToJson(t => new { id = t.Id, type = t.Type }); //推荐写法,连true都省略掉      //string jsonString = JsonHelper.ToJson(list1, t => new { id = t.Id, type = t.Type }); //不推荐该写法      //string jsonString = list1.ToJson(t => new { id = t.Id, type = t.Type }, true);      Console.WriteLine(jsonString);      //筛选出Name为"Allen"的对象      string jsonString2 = list1.ToJson(t => t.Name == "Allen"); //推荐写法,连true都省略掉      //string jsonString2 = JsonHelper.ToJson(list1, t => t.Name == "Allen"); //不推荐该写法      //string jsonString2 = list1.ToJson(t => t.Name == "Allen", true);      Console.WriteLine(jsonString2);      //筛选出Name为"Allen"的对象,并且指定json数据所需要的属性      string jsonString3 = list1.ToJson(t => t.Name == "Allen", t => new { id = t.Id, type = t.Type }); //推荐写法,连true都省略掉      //string jsonString3 = JsonHelper.ToJson(list1, t => t.Name == "Allen", t => new { id = t.Id, type = t.Type }); //不推荐该写法      //string jsonString3 = list1.ToJson(t => t.Name == "Allen", t => new { id = t.Id, type = t.Type }, true);      Console.WriteLine(jsonString3);      #endregion      #region 不过滤null对象      var list2 = new List<Test>      {        new Test {Id = 10, Type = 21, Name="Allen"},        new Test {Id = 11, Type = 22, Name="Bolong"},        new Test {Id = 12, Type = 23, Name="Popo"},        new Test {Id = 13, Type = 24, Name="Peter"},        new Test {Id = 16, Type = 25, Name="Willy"}      };      //指定json数据所需要的属性      string jsonString4 = list2.ToJson(t => new { id = t.Id, type = t.Type }, false);      Console.WriteLine(jsonString4);      //筛选出Name为"Allen"的对象      string jsonString5 = list2.ToJson(t => t.Name == "Allen", false);      Console.WriteLine(jsonString5);      //筛选出Name为"Allen"的对象,并且指定json数据所需要的属性      string jsonString6 = list2.ToJson(t => t.Name == "Allen", t => new { id = t.Id, type = t.Type }, false);      Console.WriteLine(jsonString6);      #endregion      //FromJson<T> 方法 Test      List<Test> testList1 = jsonString.FromJson<List<Test>>();      List<Test> testList2 = jsonString2.FromJson<List<Test>>();      Test test = jsonString3.FromJson<Test>();      //弱类型 Test      var test2 = jsonString.FromJson();      Newtonsoft.Json.Linq.JArray test3 = test2;      Console.ReadKey();    }  }  internal class Test  {    public int Type { get; set; }    public int Id { get; set; }    public string Name { get; set; }  }

 

PS:有更好的封装建议吗?