VBMAN.Json - JSON 操作对象

概述

VBMAN.Json 提供了 JSON 数据的解析和生成功能，支持嵌套对象、数组，是 VB6 中处理 JSON 数据的首选方案。

核心特性

• 双向转换: 支持 JSON 字符串解析和对象编码
• 嵌套支持: 无限层级的嵌套对象和数组
• 类型安全: 自动处理数据类型转换
• 格式化输出: 支持缩进美化输出
• 链式构建: 流畅的 JSON 构建 API

属性

属性	类型	说明
Root	cJson	根节点对象
Item(key)	Variant	访问指定键的值（默认成员）

方法

Encode

将对象编码为 JSON 字符串

Public Function Encode(Optional obj As Object, Optional Indent As Integer = 0, Optional UseDoubleQuotes As Boolean = True) As String

参数:

• obj - 要编码的对象（默认使用 Root）
• Indent - 缩进空格数（0=不换行）
• UseDoubleQuotes - 使用双引号（默认 True）

示例:

' 简单编码
Dim json As New cJson
json("name") = "张三"
json("age") = 25

Dim jsonStr As String
jsonStr = json.Encode()
' 结果: {"name":"张三","age":25}

' 格式化输出
Dim prettyJson As String
prettyJson = json.Encode(, 2, True)
' 结果:
' {
'   "name": "张三",
'   "age": 25
' }

Decode

解析 JSON 字符串

Public Function Decode(jsonString As String) As cJson

示例:

' 解析 JSON
Dim jsonStr As String
jsonStr = "{\"name\":\"张三\",\"age\":25}"

Dim json As cJson
Set json = VBMAN.Json.Decode(jsonStr)

Debug.Print json("name")   ' 张三
Debug.Print json("age")    ' 25

Item

访问或设置值

' 读取
Dim value As Variant
value = json("key")

' 写入
json("key") = "value"
json("number") = 123
json("bool") = True

NewItem / NewItems

创建嵌套对象/数组

Public Function NewItem() As cJson
Public Function NewItems(key As String) As cJson

示例:

' 创建嵌套对象
Dim user As New cJson
user("id") = 1
user("name") = "张三"

With user.NewItem("address")
    .Item("city") = "北京"
    .Item("zip") = "100000"
End With

' 创建数组
Dim users As New cJson

With users.NewItems("data")
    With .NewItem()
        .Item("name") = "张三"
        .Item("age") = 25
    End With
    With .NewItem()
        .Item("name") = "李四"
        .Item("age") = 30
    End With
End With

Debug.Print users.Encode(, 2)
' 结果:
' {
'   "data": [
'     {"name":"张三","age":25},
'     {"name":"李四","age":30}
'   ]
' }

Exists

检查键是否存在

Public Function Exists(key As String) As Boolean

示例:

If json.Exists("email") Then
    Debug.Print json("email")
Else
    Debug.Print "email 不存在"
End If

Remove

删除键

Public Sub Remove(key As String)

综合示例

示例1: 构建复杂 JSON

Private Sub BuildComplexJson()
    Dim root As New cJson
    
    ' 基本信息
    root("status") = "success"
    root("message") = "操作成功"
    root("timestamp") = Format(Now, "yyyy-MM-ddThh:mm:ss")
    
    ' 用户数据数组
    With root.NewItems("users")
        ' 第一个用户
        With .NewItem()
            .Item("id") = 1
            .Item("name") = "张三"
            .Item("email") = "zhangsan@example.com"
            
            ' 嵌套地址
            With .NewItem("address")
                .Item("province") = "北京"
                .Item("city") = "北京市"
                .Item("detail") = "朝阳区xxx街道"
            End With
            
            ' 嵌套订单数组
            With .NewItems("orders")
                With .NewItem()
                    .Item("order_id") = "ORD001"
                    .Item("amount") = 199.99
                End With
                With .NewItem()
                    .Item("order_id") = "ORD002"
                    .Item("amount") = 299.99
                End With
            End With
        End With
        
        ' 第二个用户
        With .NewItem()
            .Item("id") = 2
            .Item("name") = "李四"
            .Item("email") = "lisi@example.com"
        End With
    End With
    
    ' 分页信息
    With root.NewItem("pagination")
        .Item("page") = 1
        .Item("page_size") = 20
        .Item("total") = 100
    End With
    
    ' 输出 JSON
    Dim jsonStr As String
    jsonStr = root.Encode(, 2, True)
    Debug.Print jsonStr
End Sub

示例2: 解析 API 响应

Private Sub ParseApiResponse(response As String)
    Dim json As cJson
    Set json = VBMAN.Json.Decode(response)
    
    ' 检查状态
    If json("status") = "success" Then
        ' 获取用户数组
        Dim users As cJson
        Set users = json("data")("users")
        
        ' 遍历用户
        Dim i As Integer
        For i = 0 To users.Count - 1
            Dim user As cJson
            Set user = users(i)
            
            Debug.Print "ID: " & user("id")
            Debug.Print "Name: " & user("name")
            Debug.Print "Email: " & user("email")
            
            ' 检查是否有地址
            If user.Exists("address") Then
                Debug.Print "City: " & user("address")("city")
            End If
            
            Debug.Print "---"
        Next i
        
        ' 获取分页信息
        Debug.Print "Total: " & json("data")("pagination")("total")
    Else
        Debug.Print "Error: " & json("message")
    End If
End Sub

示例3: 在实际项目中使用（来自 demos）

' 构建 JSON 响应
Public Sub Json(ctx As cHttpServerContext)
    Dim ID As Long: ID = ctx.Request.QueryString("id")
    
    With New cJson
        .Item("id") = ID
        .Item("face") = ChrW(&H263A)
        .Item("timestamp") = Now
        .Item("status") = "success"
        
        ctx.Response.Json .Root
    End With
End Sub

' 解析请求数据
Public Sub HandleRequest(ctx As cHttpServerContext)
    Dim requestData As String
    requestData = ctx.Request.Body
    
    Dim json As cJson
    Set json = VBMAN.Json.Decode(requestData)
    
    Dim username As String
    Dim password As String
    
    username = json("username")
    password = json("password")
    
    ' 处理登录...
End Sub

示例4: 数据库记录转 JSON

Private Sub RecordsetToJson(rs As ADODB.Recordset)
    Dim root As New cJson
    
    ' 添加元数据
    root("count") = rs.RecordCount
    root("timestamp") = Now
    
    ' 添加数据数组
    With root.NewItems("data")
        Do While Not rs.EOF
            With .NewItem()
                Dim i As Integer
                For i = 0 To rs.Fields.Count - 1
                    .Item(rs.Fields(i).Name) = rs.Fields(i).Value
                Next i
            End With
            rs.MoveNext
        Loop
    End With
    
    ' 输出
    Debug.Print root.Encode(, 2)
End Sub

示例5: INI 配置转 JSON

Private Sub IniToJson()
    VBMAN.Ini.LoadFrom App.Path & "\\config.ini"
    
    Dim json As New cJson
    
    ' 转换所有 Section
    Dim sectionKey As Variant
    For Each sectionKey In VBMAN.Ini.Root.Keys
        With json.NewItem(CStr(sectionKey))
            Dim key As Variant
            For Each key In VBMAN.Ini.Root(sectionKey).Keys
                .Item(key) = VBMAN.Ini.Root(sectionKey)(key)
            Next key
        End With
    Next sectionKey
    
    ' 保存为 JSON 文件
    VBMAN.FileEx.SetBufferText(json.Encode(, 2), "UTF-8").SaveData App.Path & "\\config.json"
End Sub

最佳实践

1. 使用参数: 构建 JSON 时尽量使用 NewItem/NewItems
2. 检查存在性: 读取前使用 Exists 检查键是否存在
3. 错误处理: 解析 JSON 时添加错误处理
4. 类型注意: VB6 是弱类型，注意数值和字符串的区别
5. 格式化输出: 调试时使用缩进格式化便于阅读