c# 解析JSON的几种办法

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
    }
  }
]