Json_encode缺少数据

Question

我有以下结构，你可以看到json中没有返回“方法”数据。为什么？ 这是一个UML建模程序。

object(UClass)[1]
  public 'classname' => string 'Class_Temp_1311967657' (length=21)
  public 'classtype' => string 'public' (length=6)
  public 'methods' => 
    array
      0 => 
        object(UFunction)[2]
          private 'name' => string 'Bill' (length=4)
          private 'type' => null
          private 'attributes' => null
          private 'returntype' => null
      1 => 
        object(UFunction)[3]
          private 'name' => string 'Function_Temp_1311967657' (length=24)
          private 'type' => null
          private 'attributes' => null
          private 'returntype' => null
  public 'attributes' => 
    array
      'person' => 
        array
          'type' => string 'string' (length=6)
          'visability' => string 'public' (length=6)
      'id' => 
        array
          'type' => string 'int' (length=3)
          'visability' => string 'public' (length=6)
  private 'interfacesUsed' => 
    array
      empty

json看起来像这样

{"classname":"Class_Temp_1311967657","classtype":"public","methods":[{},{}],"attributes":{"person":{"type":"string","visability":"public"},"id":{"type":"int","visability":"public"}}}

Answer 1

因为私有成员未被json_encode序列化。