分享基于.NET动态编译&Newtonsoft.Json封装实现JSON转换器（JsonConverter）原理及JSON操作技巧

private List<string> Parse(string csCode)
{ var provider = new CSharpCodeProvider();
var cp = new CompilerParameters();
cp.GenerateExecutable = false;
cp.GenerateInMemory = true;
cp.IncludeDebugInformation = false;
//cp.ReferencedAssemblies.Add("mscorlib.dll");
cp.ReferencedAssemblies.Add("System.dll");
cp.ReferencedAssemblies.Add("System.Data.dll");
cp.ReferencedAssemblies.Add("System.Linq.dll");
cp.ReferencedAssemblies.Add("System.ComponentModel.DataAnnotations.dll");
cp.ReferencedAssemblies.Add("Newtonsoft.Json.dll"); CompilerResults result = provider.CompileAssemblyFromSource(cp, csCode);
List<string> errList = new List<string>();
if (result.Errors.Count > 0)
{
foreach (CompilerError err in result.Errors)
{
errList.Add(string.Format("Line:{0},ErrorNumber:{1},ErrorText:{2}", err.Line, err.ErrorNumber, err.ErrorText));
} MessageBox.Show("Compile error:\n" + string.Join("\n", errList));
return null;
} dyAssembly = result.CompiledAssembly; return dyAssembly.GetTypes().Select(t => t.FullName).ToList();
} private string ToJsonString(string targetType)
{
if (dyAssembly == null)
{
MessageBox.Show("dyAssembly is null!");
return null;
}
var type = dyAssembly.GetType(targetType);
var typeConstructor = type.GetConstructor(Type.EmptyTypes);
var obj = typeConstructor.Invoke(null);
return JsonConvert.SerializeObject(obj, Formatting.Indented, new JsonSerializerSettings { DateFormatString = "yyyy-MM-dd HH:mm:ss" });
}

private string ToClassCode(JObject jObject, string className)
{
var classCodes = new Dictionary<string, string>();
classCodes.Add(className, BuildClassCode(jObject, className, classCodes)); StringBuilder codeBuidler = new StringBuilder();
foreach (var code in classCodes)
{
codeBuidler.AppendLine(code.Value);
} return codeBuidler.ToString(); } private Dictionary<JTokenType, string> jTokenBaseTypeMappings = new Dictionary<JTokenType, string> {
{ JTokenType.Integer,"int" },{ JTokenType.Date,"DateTime" },{ JTokenType.Bytes,"byte[]"},{ JTokenType.Boolean,"bool"},{ JTokenType.String,"string"},
{ JTokenType.Null,"object"},{ JTokenType.Float,"float"},{ JTokenType.TimeSpan,"long"}
}; private string BuildClassCode(JObject jObject, string className, Dictionary<string, string> classCodes)
{
StringBuilder classBuidler = new StringBuilder();
classBuidler.Append("public class " + className + " \r\n { \r\n");
foreach (var jProp in jObject.Properties())
{
string propClassName = "object"; if (jProp.Value.Type == JTokenType.Object)
{ if (jProp.Value.HasValues)
{
propClassName = GetClassName(jProp.Name);
if (classCodes.ContainsKey(propClassName))
{
propClassName = className + propClassName;
} classCodes.Add(propClassName, BuildClassCode((JObject)jProp.Value, propClassName, classCodes));
} classBuidler.AppendFormat("public {0} {1} {2}\r\n", propClassName, jProp.Name, "{get;set;}");
}
else if (jProp.Value.Type == JTokenType.Array)
{
if (jProp.Value.HasValues)
{
var jPropArrItem = jProp.Value.First;
if (jPropArrItem.Type == JTokenType.Object)
{
propClassName = GetClassName(jProp.Name);
if (classCodes.ContainsKey(propClassName))
{
propClassName = className + propClassName;
}
propClassName += "Item"; classCodes.Add(propClassName, BuildClassCode((JObject)jPropArrItem, propClassName, classCodes));
}
else
{
if (jTokenBaseTypeMappings.ContainsKey(jPropArrItem.Type))
{
propClassName = jTokenBaseTypeMappings[jPropArrItem.Type];
}
else
{
propClassName = jPropArrItem.Type.ToString();
}
}
} classBuidler.AppendFormat("public List<{0}> {1} {2}\r\n", propClassName, jProp.Name, "{get;set;}"); }
else
{
if (jTokenBaseTypeMappings.ContainsKey(jProp.Value.Type))
{
propClassName = jTokenBaseTypeMappings[jProp.Value.Type];
}
else
{
propClassName = jProp.Value.Type.ToString();
} classBuidler.AppendFormat("public {0} {1} {2} \r\n", propClassName, jProp.Name, "{get;set;}");
} } classBuidler.Append("\r\n } \r\n"); return classBuidler.ToString();
}

using Newtonsoft.Json.Linq;
using System;
using System.Collections.Generic;
using System.Linq;namespace Zuowj.EasyUtils
{
/// <summary>
/// JObject扩展类
/// author:zuowenjun
/// 2019-6-15
/// </summary>
public static class JObjectExtensions
{ /// <summary>
/// 根据Jpath查找JSON指定的属性节点值
/// </summary>
/// <param name="jObj"></param>
/// <param name="fieldPath"></param>
/// <returns></returns>
public static IEnumerable<JToken> FindJsonNodeValues(this JObject jObj, string fieldPath)
{
var tks = jObj.SelectTokens(fieldPath, true); List<JToken> nodeValues = new List<JToken>();
foreach (var tk in tks)
{
if (tk is JProperty)
{
var jProp = tk as JProperty;
nodeValues.Add(jProp.Value);
}
else
{
nodeValues.Add(tk);
}
} return nodeValues;
} /// <summary>
/// 根据Jpath查找JSON指定的属性节点并赋值
/// </summary>
/// <param name="jObj"></param>
/// <param name="fieldPath"></param>
/// <param name="value"></param>
public static void SetJsonNodeValue(this JObject jObj, string fieldPath, JToken value)
{
var tks = jObj.SelectTokens(fieldPath, true); JArray targetJArray = null;
List<int> arrIndexs = new List<int>();
foreach (var tk in tks)
{
JProperty jProp = null;
if (tk is JProperty)
{
jProp = tk as JProperty;
}
else if (tk.Parent is JProperty)
{
jProp = (tk.Parent as JProperty);
}
else if (tk.Parent is JObject)
{
jProp = (tk.Parent as JObject).Property(tk.Path.Substring(tk.Path.LastIndexOf('.') + 1));
} if (jProp != null)
{
jProp.Value = value;
}
else if (tk.Parent is JArray) //注意不能直接在for循环中对JArray元素赋值，否则会导致报错
{
targetJArray = tk.Parent as JArray;
arrIndexs.Add(targetJArray.IndexOf(tk));
}
else
{
throw new Exception("无法识别的元素");
}
} //单独对找到的数组元素进行重新赋值
if (targetJArray != null && arrIndexs.Count > 0)
{
foreach (int i in arrIndexs)
{
targetJArray[i] = value;
}
}
} /// <summary>
/// 在指定的JPath的属性节点位置前或后创建新的属性节点
/// </summary>
/// <param name="jObj"></param>
/// <param name="fieldPath"></param>
/// <param name="name"></param>
/// <param name="value"></param>
/// <param name="addBefore"></param>
/// <returns></returns>
public static void AppendJsonNode(this JObject jObj, string fieldPath, string name, JToken value, bool addBefore = false)
{
var nodeValues = FindJsonNodeValues(jObj, fieldPath); if (nodeValues == null || !nodeValues.Any()) return; foreach (var node in nodeValues)
{
var targetNode = node;
if (node is JObject) //注意只能对普能单值 的JToken对象（JProptery）允许添加，若不是则应找对应的属性信息
{
targetNode = node.Parent;
} var jProp = new JProperty(name, value);
if (addBefore)
{
targetNode.AddBeforeSelf(jProp);
}
else
{
targetNode.AddAfterSelf(jProp);
}
}
}
}
}

var jsonObj = new
{
Root = new
{
Lv1 = new
{
col1 = 123,
col2 = true,
col3 = new
{
f1 = "aa",
f2 = "bb",
f3 = "cc",
Lv2 = new
{
flv1 = 1,
flv2 = "flv2-2"
}
}
}
},
Main = new[] {
new{
mf1="x",
mf2="y",
mf3=123
},
new{
mf1="x2",
mf2="y2",
mf3=225
}
}
}; string json = JsonConvert.SerializeObject(jsonObj, Formatting.Indented); Console.WriteLine("JSON1:" + json); var jObj = JObject.FromObject(jsonObj); //JObject.Parse(json); var findResult = jObj.FindJsonNodeValues("Root.Lv1.col3.Lv2.*");
Console.WriteLine("FindJsonNodeValues:" + string.Join(",", findResult)); jObj.SetJsonNodeValue("Main[*].mf2", "*changed value*");
json = JsonConvert.SerializeObject(jObj, Formatting.Indented);
Console.WriteLine("JSON2:" + json); jObj.AppendJsonNode("Root.Lv1.col3.Lv2", "LV2-New", JObject.FromObject(new {flv21="a2",flv22=221,flv23=true }));
// jObj.AppendJsonNode("Root.Lv1.col3.Lv2", "LV2-2","single value");
json = JsonConvert.SerializeObject(jObj, Formatting.Indented);
Console.WriteLine("JSON3:" + json); Console.ReadKey();

JSON1:{
"Root": {
"Lv1": {
"col1": 123,
"col2": true,
"col3": {
"f1": "aa",
"f2": "bb",
"f3": "cc",
"Lv2": {
"flv1": 1,
"flv2": "flv2-2"
}
}
}
},
"Main": [
{
"mf1": "x",
"mf2": "y",
"mf3": 123
},
{
"mf1": "x2",
"mf2": "y2",
"mf3": 225
}
]
}
FindJsonNodeValues:1,flv2-2
JSON2:{
"Root": {
"Lv1": {
"col1": 123,
"col2": true,
"col3": {
"f1": "aa",
"f2": "bb",
"f3": "cc",
"Lv2": {
"flv1": 1,
"flv2": "flv2-2"
}
}
}
},
"Main": [
{
"mf1": "x",
"mf2": "*changed value*",
"mf3": 123
},
{
"mf1": "x2",
"mf2": "*changed value*",
"mf3": 225
}
]
}
JSON3:{
"Root": {
"Lv1": {
"col1": 123,
"col2": true,
"col3": {
"f1": "aa",
"f2": "bb",
"f3": "cc",
"Lv2": {
"flv1": 1,
"flv2": "flv2-2"
},
"LV2-New": {
"flv21": "a2",
"flv22": 221,
"flv23": true
}
}
}
},
"Main": [
{
"mf1": "x",
"mf2": "*changed value*",
"mf3": 123
},
{
"mf1": "x2",
"mf2": "*changed value*",
"mf3": 225
}
]
}