C#中的JSON封装与解析

太过爱你忘了你带给我的痛 2022-08-04 05:27 242阅读 0赞

欲成为海洋大师，必知晓海中每一滴水的真名。  
刚开始只是想找一个转换JSON数组的方法，结果在MSDN翻到一大把。  
  
搜索过程中免不了碰到一大堆名词：WCF => DataContract => DataMember => DataContractJsonSerializer，然后就是不停的引入命名空间。  
  
这一段经历，立即让我就联想到了上面引用的这句存在于某小说里面巫师的话语。静态语言真有点令人抓狂，不停的做准备，然后才可能开始工作。  
  
对比  
.NET下几种常见的解析JSON方法  
主要类 命名空间 限制 内建LINQ支持  
DataContractJsonSerializer System.Runtime.Serialization.Json 通用 否  
JavaScriptSerializer System.Web.Script.Serialization 只能在Web环境使用 否  
JsonArray、JsonObject、JsonValue System.Json 只能在Silverlight中使用 是  
JsonConvert、JArray、JObject、JValue、JProperty Newtonsoft.Json 通用 是  
准备数据  
实体类：  
  
\[DataContract\]  
public class Person  
\{  
\[DataMember(Order = 0, IsRequired = true)\]  
public string Name \{ get; set; \}  
  
\[DataMember(Order = 1)\]  
public int Age \{ get; set; \}  
  
\[DataMember(Order = 2)\]  
public bool Alive \{ get; set; \}  
  
\[DataMember(Order = 3)\]  
public string\[\] FavoriteFilms \{ get; set; \}  
  
\[DataMember(Order = 4)\]  
public Person Child \{ get; set; \}  
\}  
定义：  
  
Action<object> log = o => Console.WriteLine(o);  
Func<int, int, int> add = (x, y) => x + y;  
  
var p1 = new Person \{  
Age = 12,  
Alive = true,  
Name = "lj",  
FavoriteFilms = new\[\] \{ "Up", "Avatar" \}  
\};  
var p2 = new Person() \{ Age = 28, Name = "cy", Child = p1 \};  
  
使用DataContractJsonSerializer  
帮助类：  
  
// using System.Runtime.Serialization.Json;  
  
/// <summary>  
/// 解析JSON，仿Javascript风格  
/// </summary>  
public static class JSON  
\{  
  
public static T parse<T>(string jsonString)  
\{  
using (var ms = new MemoryStream(Encoding.UTF8.GetBytes(jsonString)))  
\{  
return (T)new DataContractJsonSerializer(typeof(T)).ReadObject(ms);  
\}  
\}  
  
public static string stringify(object jsonObject)  
\{  
using (var ms = new MemoryStream())  
\{  
new DataContractJsonSerializer(jsonObject.GetType()).WriteObject(ms, jsonObject);  
return Encoding.UTF8.GetString(ms.ToArray());  
\}  
\}  
\}  
用法：  
  
// 序列化  
var jsonString = JSON.stringify(new\[\] \{ p1, p2 \});  
log(jsonString == JSON.stringify(new List<Person>() \{ p1, p2 \})); //true  
log(jsonString);  
// 反序列化，泛型集合  
JSON.parse<List<Person>>(jsonString);  
// 数组转换  
JSON.parse<Person\[\]>(jsonString);  
输出：  
  
\[\{"Name":"lj","Age":12,"Alive":true,"FavoriteFilms":\["Up","Avatar"\],"Child":null  
\},\{"Name":"cy","Age":28,"Alive":false,"FavoriteFilms":null,"Child":\{"Name":"lj",  
"Age":12,"Alive":true,"FavoriteFilms":\["Up","Avatar"\],"Child":null\}\}\]  
使用JavaScriptSerializer  
// using System.Web.Script.Serialization;  
  
var jser = new JavaScriptSerializer();  
var json = jser.Serialize(new List<Person>() \{ p1, p2 \});  
var persons = jser.Deserialize<List<Person>>(json);  
使用Silverlight  
// using System.Json  
  
var css = "\{ \\"\#header\\" : \{background:\\"red\\"\}, layout : \[5,4,1\],color:\\"cyan\\" \}";  
  
var style = JsonObject.Parse(css) as JsonObject;  
  
(  
from s in style  
where s.Key == "color"  
select (string)s.Value  
).First().ToString();  
// "cyan"  
  
  
// 更多操作  
style\["layout"\]\[0\] = 22;  
  
var hd = style\["\#header"\];  
style\["body>div+p"\] = hd;  
style.Remove("\#header");  
  
var bd = new JsonObject();  
bd\["border"\] = "1px solid cyan";  
style\["body>div+p"\]\["\#meta"\] = bd;  
style.ToString();  
// \{"layout":\[22,4,1\],"color":"cyan","body>div+p":\{"background":"red","\#meta":\{"border":"1px solid cyan"\}\}\}  
使用JSON.NET  
// using Newtonsoft.Json;  
  
var json = JsonConvert.SerializeObject(new\[\] \{ p1, p2 \});  
var persons = JsonConvert.DeserializeObject<List<Person>>(json);  
var ja = JArray.Parse(jsonString);  
log(ja); //注意，格式化过的输出  
输出：  
  
\[  
\{  
"Name": "lj",  
"Age": 12,  
"Alive": true,  
"FavoriteFilms": \[  
"Up",  
"Avatar"  
\],  
"Child": null  
\},  
\{  
"Name": "cy",  
"Age": 28,  
"Alive": false,  
"FavoriteFilms": null,  
"Child": \{  
"Name": "lj",  
"Age": 12,  
"Alive": true,  
"FavoriteFilms": \[  
"Up",  
"Avatar"  
\],  
"Child": null  
\}  
\}  
\]  
LINQ：  
  
var ageCount = ja.Select(j => (int)j\["Age"\]).Aggregate(add);  
var q = from j in ja  
where !j\["Name"\].Value<string>().Equals("lj")  
select (int)j\["Age"\];  
  
log(q.Aggregate(add) == ageCount); //false  
其他：  
  
// 与Linq to XML 相似的嵌套构造函数：  
var jo = new JObject(  
new JProperty("age", persons.Select( p => p.Age)),  
new JProperty("funny", true),  
new JProperty("array", new JArray(new\[\] \{ 2, 4, 1 \}))  
);  
log(jo);  
  
// JObject 操作  
var css = "\{ \\"\#header\\" : \{background:\\"red\\"\}, layout : \[5,4,1\] \}";  
var style = JObject.Parse(css);  
  
var bd = new JObject();  
bd\["color"\] = "1px solid cyan";  
  
style\["border"\] = bd;  
  
var hd = style\["\#header"\];  
style\["body>div+p"\] = hd;  
  
hd.Parent.Remove();  
  
style\["layout"\]\[0\] = 22;  
log(style);  
输出：  
  
\{  
"age": \[  
12,  
28  
\],  
"funny": true,  
"array": \[  
2,  
4,  
1  
\]  
\}  
\{  
"layout": \[  
22,  
4,  
1  
\],  
"border": \{  
"color": "1px solid cyan"  
\},  
"body>div+p": \{  
"background": "red"  
\}  
\}