扩展我的previous question,如何处理包含有效structs
的混合structs
的数组?我试过看serde_json::Value
来源了。但是它没有处理两个不同struct
的情况。
我无法简单地合并它们,并在其属性上使用选项,因为这会使单#[derive(Clone, Debug, Deserialize)]
struct WebResponse {
foo: Vec<Structs>,
}
enum Structs {
Foo(Foo),
Bar(Bar),
}
#[derive(Clone, Debug, Deserialize)]
struct Foo {
name: String,
baz: Vec<String>,
}
#[derive(Clone, Debug, Deserialize)]
struct Bar {
quux: u64
}
变得笨拙,并且对它们来说很重要。
{
"foo": [
{
"name": "John",
"baz": ["Lorem", "Ipsum"]
},
{
"quux": 17
}
]
}
public class Employee : INotifyPropertyChanged
{
public Employee()
{
_subEmployee = new ObservableCollection<Employee>();
}
private string _name;
public ObservableCollection<Employee> SubEmployee
{
get { return _subEmployee; }
set
{
_subEmployee = value;
NotifiyPropertyChanged("SubEmployee");
}
}
public string Name
{
get { return _name; }
set
{
_name = value;
NotifiyPropertyChanged("Name");
}
}
ObservableCollection<Employee> _subEmployee;
public event PropertyChangedEventHandler PropertyChanged;
void NotifiyPropertyChanged(string property)
{
if (PropertyChanged != null)
PropertyChanged(this, new PropertyChangedEventArgs(property));
}
}
答案 0 :(得分:5)
有几种方法可以解决这个问题。如果您的变体很少,最简单的方法就是手动实现Deserialize
,如下所示:
impl serde::de::Deserialize for Structs {
fn deserialize<D>(deserializer: &mut D) -> Result<Self, D::Error>
where D: serde::Deserializer,
{
deserializer.deserialize(Visitor)
}
}
struct Visitor;
impl serde::de::Visitor for Visitor {
type Value = Structs;
fn visit_map<V>(&mut self, mut visitor: V) -> Result<Structs, V::Error>
where V: serde::de::MapVisitor,
{
let s: String = try!(visitor.visit_key()).expect("got struct with no fields");
let val = match &s as &str {
"name" => {
Ok(Structs::Foo(Foo {
name: try!(visitor.visit_value()),
baz: {
let s: String = try!(visitor.visit_key()).expect("baz field");
assert_eq!(&s, "baz");
try!(visitor.visit_value())
},
}))
},
"baz" => {
Ok(Structs::Foo(Foo {
baz: try!(visitor.visit_value()),
name: {
let s: String = try!(visitor.visit_key()).expect("name field");
assert_eq!(&s, "name");
try!(visitor.visit_value())
},
}))
},
"quux" => {
Ok(Structs::Bar(Bar {
quux: try!(visitor.visit_value())
}))
},
other => panic!("no struct has field `{}`", other),
};
try!(visitor.end());
val
}
}
此实现的问题在于它显然无法扩展。您可以做的是创建一个新的Deserializer
,您可以为其找到第一个字段名称,并覆盖deserialize_map
方法以通过自定义MapVisitor
处理各种结构。< / p>
如果您认为这是其他序列化框架支持的常见情况,请随时在serde
存储库或serde-json
存储库上发布错误报告。我确信有一种方法可以自动生成这样的实现,但这肯定不是一件容易的事。