json看这个就够了

Json数据格式

json是一种与编程语言无关的数据交换的格式。使用ajax进行前后台数据交换，移动端与服务端的数据交换。

json的格式与解析

json有两种格式：
1）对象格式:{"key1":obj,"key2":obj,"key3":obj...}
2）数组格式:[obj,obj,obj...]

//以user对象为例
{"username":"lisi","age":22,"password":"123456","addr":"长沙"}

[{"pid":10,"pname":"华为p20"},{...},{...}]

注意：

• 对象格式和数组格式可以相互嵌套
• json的key是字符串 json的value是Object

//js里书写json对象
<script>
var person = {"firstname":"汪","lastname":"思源","age":22}
var persons = [{"firstname":"张","lastname":"三","age":18},{"firstname":"李","lastname":"四","age":82}];
var json = {
    "baobao":[
        {"name":"小双","age":28,"addr":"扬州"},
        {"name":"建宁","age":18,"addr":"紫禁城"},
        {"name":"阿珂","age":19,"addr":"山西"}
    ]
}

// 取person的lastname值
alert(person.lastname);

// 取persons=李
alert(persons[1].firstname);

// 取阿珂
alert(json.baobao[2].name);
</script>

Gson

// TODO

FastJson

//TODO