[英]play framework - bind enum in routes
I am building an app in java on play 2.2. 我正在使用java on play 2.2构建一个应用程序。
I have a java enum as a parameter in a function that I use in routes. 我有一个java枚举作为我在路由中使用的函数中的参数。
This is my enum class. 这是我的enum课程。 I searched around and found out I need to implements QueryStringBindable to use it in routes.
我四处搜索,发现我需要实现QueryStringBindable才能在路由中使用它。
public enum Something implements QueryStringBindable<Something> {
a,
b,
c;
@Override
public F.Option<ClientStatus> bind(String key, Map<String, String[]> params) {
String[] arr = params.get(key);
if (arr == null || arr.length == 0) {
return F.Option.None();
} else {
Something status = Something.valueOf(arr[0]);
return F.Option.Some(status);
}
}
@Override
public String unbind(String key) {
return null;
}
@Override
public String javascriptUnbind() {
return null;
}
}
Yet I tried in my routes: 然而我尝试了我的路线:
GET /someurl controllers.Application.function(status: util.enums.Something)
But it returns bad request with error message as: 但它返回错误消息的错误请求:
For request 'GET /someurl' [util.enums.Something]
要求'GET / someurl'[util.enums.Something]
I googled and didn't find any answer working in my case. 我用谷歌搜索,并没有找到任何答案在我的情况下工作。 Did I miss something or play doesn't support binding enums?
我错过了什么或玩不支持绑定枚举?
I had the same problem and I finally found out that it is not solvable as is. 我有同样的问题,我终于发现它不能解决。
By reading the documentation for PathBindable
and QueryStringBindable
I found that play framework requires the Bindable to provide a No Argument public constructor. 通过阅读
PathBindable
和QueryStringBindable
的文档,我发现play框架需要 Bindable提供No Argument公共构造函数。 Which by definition is no possible with enum
in Java. 根据定义,Java中的
enum
是不可能的。
So I had to wrap my enum to solve this. 所以我不得不用我的枚举来解决这个问题。 In your example we would have something like:
在你的例子中我们会有类似的东西:
public enum Something {
a,
b,
c;
public static class Bound implements QueryStringBindable<Bound>{
private Something value;
@Override
public F.Option<ClientStatus> bind(String key, Map<String, String[]> params) {
String[] arr = params.get(key);
if (arr != null && arr.lenght > 0) {
this.value = Something.valueOf(arr[0]);
return F.Option.Some(this);
} else {
return F.Option.None();
}
}
@Override
public String unbind(String key) {
return this.value.name();
}
@Override
public String javascriptUnbind() {
return this.value.name();
}
public Something value(){
return this.value;
}
}
}
and then you have to use the type some.package.Something.Bound
as a type in your routes file. 然后你必须使用
some.package.Something.Bound
类型作为路由文件中的类型。
EDIT: using that in a template is slightly more tricky. 编辑:在模板中使用它稍微有点棘手。 And you have to know a bit of scala.
你必须知道一点scala。 To follow @Aleksei's comment
关注@Aleksei的评论
<a href="@routes.MyController.showStuff(myEnumVar)">link</a>
should become 应该成为
<a href="@{
routes.MyController.showStuff(new MyEnumVarWrapper(myEnumVar)).url
}">link</a>
I want to offer a small correction to the answer: (The return type isn't ClientStatus, and the unbind function should use the key parameter, it's for the url generatiion) 我想对答案提供一个小的修正:(返回类型不是ClientStatus,unbind函数应该使用key参数,它是url generatiion)
public enum Something {
a,
b,
c;
public static class Bound implements QueryStringBindable<Bound>{
private Something value;
@Override
public F.Option<Bound> bind(String key, Map<String, String[]> params) {
String[] arr = params.get(key);
if (arr != null && arr.lenght > 0) {
this.value = Something.valueOf(arr[0]);
return F.Option.Some(this);
} else {
return F.Option.None();
}
}
@Override
public String unbind(String key) {
return key + "=" + this.value.name();
}
@Override
public String javascriptUnbind() {
return this.value.name();
}
public Something value(){
return this.value;
}
}
} }
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