在 Qt 中支持 JSON ¶

JSON 是结构化数据存储格式。它有 6 种基本数据类型：

• bool

• double

• string

• array

• object

• null

A value can have any of the above types. A boolean value is represented by the strings true or false in JSON. JSON doesn’t explicitly specify the valid range for numbers, but the support in Qt is limited to the validity range and precision of doubles. A string can be any valid unicode string. An array is a list of values, and an object is a collection of key/value pairs. All keys in an object are strings, and an object cannot contain any duplicate keys.

The text representation of JSON encloses arrays in square brackets ([ … ]) and objects in curly brackets ({ … }). Entries in arrays and objects are separated by commas. The separator between keys and values in an object is a colon (:).

简单 JSON 文档编码一个人、他/她的年龄、地址及电话号码看起来像：

{
    "FirstName": "John",
    "LastName": "Doe",
    "Age": 43,
    "Address": {
        "Street": "Downing Street 10",
        "City": "London",
        "Country": "Great Britain"
    },
    "Phone numbers": [
        "+44 1234567",
        "+44 2345678"
    ]
}
											

以上范例由 5 个键/值对的对象组成。二个值是字符串，一个是数字，一个是其它对象，最后一个是数组。

有效 JSON 文档是数组 (或对象)，因此文档始终以方括号 (或花括号) 开头。

所有 JSON 类都是基于值的， 隐式共享类 .

Qt 中的 JSON 支持由这些类组成：