c#操作json示例分享

1..net对json的支持介绍

(1)操作json的dll介绍

.net自身有system.runtime.serialization.dll与system.web.extensions.dll，使用这两个dll可以把对象序列化和反序列化成json数据。也可以使用第三方的newtonsoft.json.dll来操作json数据，使用它会更方便的操作json数据，其功能也跟强一些。

(2)使用system.web.extensions.dll的限制

要使用system.web.extensions.dll必须是在web项目中，只有在web项目中才能引用此dll。

2.json序列化和反序列化

(1)使用newtonsoft.json.dll实现

代码示例：

public class person
{
public string name;//姓名
public bool sex;//性别，是否是男
public person(string name, bool sex)
{
this.name = name;
this.sex = sex;
}
public override string tostring()
{
return "姓名：" + this.name + "\t性别：" + (this.sex ? "男" : "女");
}
}
public class programmer : person
{
public list<string> languages;//编程语言
public programmer(string name, bool sex, list<string> languages) : base(name, sex)
{
this.languages = languages;
}
public override string tostring()
{
stringbuilder str = new stringbuilder();
str.append(base.tostring() + "\t编程语言：");
foreach (string l in this.languages)
{
str.append(l + " ");
}
return str.tostring();
}
}
class program
{
static void main(string[] args)
{
string filepath = @"d:\users\lizw\桌面\objectjson.txt";
list<string> languages = null;
list<programmer> list = new list<programmer>();
languages = new list<string>(new string[] { "c#", "java" });
list.add(new programmer("*伟", true, languages));
languages = new list<string>(new string[] { "c#", "c++" });
list.add(new programmer("coder2", false, languages));
languages = new list<string>(new string[] { "c#", "c++", "c", "java" });
list.add(new programmer("coder3", true, languages));
//序列化对象
string jsonstr = jsonconvert.serializeobject(list);//将对象转换成json存储
file.writealltext(filepath, jsonstr);
list.clear();
//反序列化对象
list = jsonconvert.deserializeobject<list<programmer>>(jsonstr);
foreach (programmer p in list)
{
console.writeline(p);
}
console.writeline("ok!");
console.read();
}
}

得到的json文本：

[{"languages":["c#","java"],"name":"*伟","sex":true},

{"languages":["c#","c++"],"name":"coder2","sex":false},

{"languages":["c#","c++","c","java"],"name":"coder3","sex":true}]

注意：此种方式json序列化对象时，只能序列化对象的公有成员。

(2)使用system.web.extensions.dll实现

代码示例：

public class person

{

public string name;//姓名

public bool sex;//性别，是否是男

public person() { }//必须有此构造方法，否者无法反序列化

public person(string name, bool sex)

{

this.name = name;

this.sex = sex;

}

public override string tostring()

{

return "姓名：" + this.name + "\t性别：" + (this.sex ? "男" : "女");

}

}

public class programmer : person

{

public list<string> languages;//编程语言

public programmer() { }//必须有此构造方法，否者无法反序列化

public programmer(string name, bool sex, list<string> languages)

: base(name, sex)

{

this.languages = languages;

}

public override string tostring()

{

stringbuilder str = new stringbuilder();

str.append(base.tostring() + "\t编程语言：");

foreach (string l in this.languages)

{

str.append(l + " ");

}

return str.tostring();

}

}

public partial class webform1 : system.web.ui.page

{

protected void page_load(object sender, eventargs e)//web页面的加载事件

{

list<string> languages = null;

list<programmer> list = new list<programmer>();

languages = new list<string>(new string[] { "c#", "java" });

list.add(new programmer("*伟", true, languages));

languages = new list<string>(new string[] { "c#", "c++" });

list.add(new programmer("coder2", false, languages));

languages = new list<string>(new string[] { "c#", "c++", "c", "java" });

list.add(new programmer("coder3", true, languages));

//序列化对象

javascriptserializer jsonserialize = new javascriptserializer();

string jsonstr = jsonserialize.serialize(list);//将对象转换成json存储

response.write(jsonstr + "<br>");//前台输出

//反序列化对象

list.clear();

list = jsonserialize.deserialize<list<programmer>>(jsonstr);

foreach (programmer p in list)

{

response.write(p + "<br>");//前台输出

}

}

}

得到的json文本：

[{"languages":["c#","java"],"name":"*伟","sex":true},

{"languages":["c#","c++"],"name":"coder2","sex":false},

{"languages":["c#","c++","c","java"],"name":"coder3","sex":true}]

注意：此种方式json序列化对象时，除了只能序列化对象的公有成员外，被序列化的对象还必须有无参的构造方法才能被反序列化！system.web.extensions.dll只能在web项目中引用，在控制台和winfrom项目中无法引用！

(3)使用system.runtime.serialization.dll实现

代码示例：

[datacontract]//必须申明，否则无法序列化

public class person

{

[datamember(name = "姓名")]//必须申明，否则无法序列化

private string name;

[datamember(name = "性别")]//必须申明，否则无法序列化

private bool sex;

public person(string name, bool sex)

{

this.name = name;

this.sex = sex;

}

public override string tostring()

{

return "姓名：" + this.name + "\t性别：" + (this.sex ? "男" : "女");

}

}

[datacontract]

public class programmer : person

{

[datamember(name = "编程语言")]

private list<string> languages;

public programmer(string name, bool sex, list<string> languages)

: base(name, sex)

{

this.languages = languages;

}

public override string tostring()

{

stringbuilder str = new stringbuilder();

str.append(base.tostring() + "\t编程语言：");

foreach (string l in this.languages)

{

str.append(l + " ");

}

return str.tostring();

}

}

class program

{

static void main(string[] args)

{

string filepath = @"d:\users\lizw\桌面\objectjson.txt";

list<string> languages = null;

list<programmer> list = new list<programmer>();

languages = new list<string>(new string[] { "c#", "java" });

list.add(new programmer("*伟", true, languages));

languages = new list<string>(new string[] { "c#", "c++" });

list.add(new programmer("coder2", false, languages));

languages = new list<string>(new string[] { "c#", "c++", "c", "java" });

list.add(new programmer("coder3", true, languages));

//序列化对象

datacontractjsonserializer ser =

new datacontractjsonserializer(typeof(list<programmer>));

memorystream ms = new memorystream();

ser.writeobject(ms, list);//将对象转换成json存储

string jsonstr = encoding.utf8.getstring(ms.toarray());

file.writealltext(filepath, jsonstr);

//反序列化对象

list.clear();

ms.position = 0;

list = (list<programmer>)ser.readobject(ms);

foreach (programmer p in list)

{

console.writeline(p);

}

ms.dispose();//关闭内存流

console.writeline("ok!");

console.read();

}

}
[code]

得到的json文本：

[{"姓名":"*伟","性别":true,"编程语言":["c#","java"]},

{"姓名":"coder2","性别":false,"编程语言":["c#","c++"]},

{"姓名":"coder3","性别":true,"编程语言":["c#","c++","c","java"]}]

注意：此种方式json序列化对象时，可以序列化对象的任意成员(包括私有成员)，但是使用此方式必须要在类和成员的定义处加上相应的特性(具体请参考代码)。

(4)小结

3.解析json字符串(使用newtonsoft.json.dll)

(1)使用jsontextreader类进行只进读取(不常用)
[code]
class program

{

static void main(string[] args)

{

//json字符串

string jsonstr = @"

[{'languages':['c#','java'],'name':'*伟','sex':true},

{'languages':['c#','c++'],'name':'coder2','sex':false},

{'languages':['c#','c++','c','java'],'name':'coder3','sex':true}]";

jsontextreader json = new jsontextreader(new stringreader(jsonstr));

while (json.read())

{

console.writeline(json.value + "--" + json.tokentype + "--" + json.valuetype);

}

console.writeline("ok!");

console.read();

}

}

(2)使用jarray、jobject、jtoken进行读取(常用)

class program

{

static void main(string[] args)

{

//json字符串

string jsonstr = @"

[{'languages':['c#','java'],'name':'*伟','sex':true},

{'languages':['c#','c++'],'name':'coder2','sex':false},

{'languages':['c#','c++','c','java'],'name':'coder3','sex':true}]";

jarray ja = (jarray)jsonconvert.deserializeobject(jsonstr);

foreach (jtoken jt in ja)

{

jobject jo = (jobject)jt;

jarray temp = (jarray)jo["languages"];

foreach (jtoken token in temp)

{

console.write(token+" ");

}

console.writeline("\t" + jo["name"] + "\t" + jo["sex"]);

}

console.writeline("ok!");

console.read();

}

}

(3)json时间字符串的处理

class program

{

static void main(string[] args)

{

datetime time = datetime.now;

//这里使用自定义日期格式

isodatetimeconverter timeconverter = new isodatetimeconverter();

timeconverter.datetimeformat = "北京时间：yyyy-mm-dd hh:mm:ss";

//序列化时间

string jsonstr = jsonconvert.serializeobject(time, timeconverter);

console.writeline(jsonstr);

//反序列化时间

datetime time2 = jsonconvert.deserializeobject<datetime>(jsonstr, timeconverter);

console.writeline(time2);

console.writeline("ok!");

console.read();

}

}

4.读取json字符串的技巧

(1)使用匿名类

class program

{

static void main(string[] args)

{

//json字符串

string jsonstr = @"{'languages':['c#','java'],'name':'*伟','sex':true}";

//创建匿名类

var tempclass = new { languages = new string[0], name = string.empty, sex = false };

//反序列化

var o = jsonconvert.deserializeanonymoustype(jsonstr, tempclass);

console.writeline(o.name+"\t"+o.sex+"\t"+o.languages[1]);

console.read();

}

}

(2)使用索引器

class program

{

static void main(string[] args)

{

//json字符串

string jsonstr = @"{'languages':['c#','java'],'name':'*伟','sex':true}";

//反序列化

jobject o = jsonconvert.deserializeobject(jsonstr) as jobject;

//使用索引器访问

console.writeline(o["name"] + "\t" + o["sex"] + "\t" + o["languages"][1]);

console.read();

}
}