Ruby on rails 序列化为xml时出现NoMethodError

我试图从数据库中获取一些模型对象并将它们序列化为xml，但是当包含一个特定的（有很多）关联时，我会得到以下错误。JSON序列化（to_JSON）可以正常工作（也包括属性）。还有一个对象（XML和JSON）的序列化。有什么问题吗？（模型类不覆盖任何XML序列化内容，我使用的是Rails 3）

下面是命令：

Entity.all.to_xml:include=>：properties

和转储：

NoMethodError: undefined method `macro' for nil:NilClass from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/activesupport-3.0.1/lib/active_support/whiny_nil.rb:48:in `method_missing' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/activerecord-3.0.1/lib/active_record/serialization.rb:41:in `serializable_add_includes' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/activerecord-3.0.1/lib/active_record/serialization.rb:40:in `each' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/activerecord-3.0.1/lib/active_record/serialization.rb:40:in `serializable_add_includes' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/activerecord-3.0.1/lib/active_record/serializers/xml_serializer.rb:191:in `send' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/activerecord-3.0.1/lib/active_record/serializers/xml_serializer.rb:191:in `add_includes' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/activerecord-3.0.1/lib/active_record/serializers/xml_serializer.rb:186:in `add_extra_behavior' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/activemodel-3.0.1/lib/active_model/serializers/xml.rb:103:in `serialize' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/builder-2.1.2/lib/builder/xmlbase.rb:134:in `call' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/builder-2.1.2/lib/builder/xmlbase.rb:134:in `_nested_structures' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/builder-2.1.2/lib/builder/xmlbase.rb:58:in `method_missing' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/builder-2.1.2/lib/builder/xmlbase.rb:31:in `tag!' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/activemodel-3.0.1/lib/active_model/serializers/xml.rb:101:in `serialize' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/activerecord-3.0.1/lib/active_record/serializers/xml_serializer.rb:175:in `to_xml' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/activerecord-3.0.1/lib/active_record/associations/association_proxy.rb:218:in `send' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/activerecord-3.0.1/lib/active_record/associations/association_proxy.rb:218:in `method_missing' ... 5 levels... from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/builder-2.1.2/lib/builder/xmlbase.rb:134:in `call' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/builder-2.1.2/lib/builder/xmlbase.rb:134:in `_nested_structures' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/builder-2.1.2/lib/builder/xmlbase.rb:58:in `method_missing' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/builder-2.1.2/lib/builder/xmlbase.rb:31:in `tag!' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/activemodel-3.0.1/lib/active_model/serializers/xml.rb:101:in `serialize' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/activerecord-3.0.1/lib/active_record/serializers/xml_serializer.rb:175:in `to_xml' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/activesupport-3.0.1/lib/active_support/xml_mini.rb:107:in `to_tag' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/activesupport-3.0.1/lib/active_support/core_ext/array/conversions.rb:159:in `to_xml' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/activesupport-3.0.1/lib/active_support/core_ext/array/conversions.rb:159:in `each' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/activesupport-3.0.1/lib/active_support/core_ext/array/conversions.rb:159:in `to_xml' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/builder-2.1.2/lib/builder/xmlbase.rb:134:in `call' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/builder-2.1.2/lib/builder/xmlbase.rb:134:in `_nested_structures' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/builder-2.1.2/lib/builder/xmlbase.rb:58:in `method_missing' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/activesupport-3.0.1/lib/active_support/core_ext/array/conversions.rb:158:in `__send__' from /home/kai/.rvm/gems/ruby-1.8.7-p302@projectx/gems/activesupport-3.0.1/lib/active_support/core_ext/array/conversions.rb:158:in `to_xml' 实体迁移中存在由创建的

整数字段。似乎当您将“属于”关联命名为与：foreign\u键相同时，XML序列化就会中断。当我更改为
属于\u to:creator，：class\u name=>“User”，：foreign\u key=>“created\u by”
时，序列化将按预期工作

更新的更新的更新；-）
这已经在Rails 3.0.3中解决了（我有3.0.1）。那么我学到了什么。。。首先更新软件
 模型关系很可能未正确设置。
您是否能够做到：

e = Entity.find.first
e.properties
e=实体.find.first
e、 性质
并让它返回相关对象？
是的，它返回。正如我所提到的，相同的命令在相同的数据库状态下运行，但是只使用to_json就可以了（所有属性都正确地序列化为json）。
e = Entity.find.first
e.properties