JSON (JavaScript Object Notation) is a lightweight data-interchange format. It is easy for humans to read and write. It is easy for machines to parse and generate. It is based on a subset of the JavaScript Programming Language,Standard ECMA-262 3rd Edition – December 1999. JSON is a text format that is completely language independent but uses conventions that are familiar to programmers of the C-family of languages,including C,C++,C#,Java,JavaScript,Perl,Python,and many others. These properties make JSON an ideal data-interchange language.

参考号：json.org

一个对象是一组无序的名称/值对.一个对象以{(左括号)开始,以}(右括号)结尾.每个名称后跟：(冒号),名称/值对由((逗号))分隔.

alt text http://www.json.org/object.gif

数组是值的有序集合.阵列以[(左括号)]开始,以](右括号)结尾.值由((逗号)分隔).

alt text http://www.json.org/array.gif

值可以是双引号的字符串,也可以是数字,或true或false或null,或对象或数组.这些结构可以嵌套.

alt text http://www.json.org/value.gif

字符串是零个或多个Unicode字符的集合,用双引号括起来,使用反斜杠转义.字符表示为单个字符串.一个字符串非常像一个C或Java字符串.

alt text http://www.json.org/string.gif

数字非常像C或Java编号,不同之处在于不使用八进制和十六进制格式.
alt text http://www.json.org/number.gif

这是一个例子：

{
    "menu": {
        "id": "file","value": "File","popup": {
            "menuitem": [{
                "onclick": "CreateNewDoc()"
            },{
                "value": "Open","onclick": "OpenDoc()"
            },{
                "value": "Close","onclick": "CloseDoc()"
            }]
        }
    }
}

在XML中也是一样的：

<menu id="file" value="File">
  <popup>
    <menuitem value="New" onclick="CreateNewDoc()" />
    <menuitem value="Open" onclick="OpenDoc()" />
    <menuitem value="Close" onclick="CloseDoc()" />
  </popup>
</menu>

参考号：json.org

希望你现在知道什么是JSON.