如何使用Play 2.0路由绑定双参数 [英] How to bind Double parameter with Play 2.0 routing
问题描述
我可以通过获取参数为String并在控制器中解析这些参数,但可以在这里使用自动绑定吗?
现在,我第一次尝试简单有一个双重值:
GET / events / foo controllers.Application.foo(doublevalue:Double)
与
public static结果foo(Double doublevalue){
return ok(index.render(Foo:+ doublevalue));
}
我得到的是没有找到类型Double的QueryString binder。尝试为此类型实现一个隐式的QueryStringBindable。
我是否错过了已经提供的东西,或者
我必须自定义QueryStringBindable分析双倍
目前2.0),Java绑定只适用于自递归类型。也就是说,类型如下所示:
class Foo extends QueryStringBindable&Foo> {
...
}
所以,如果你想定义一个 java.lang.Double
,它是一种现有类型的Java,您需要将其包装为自递归类型。例如:
package util;
public class DoubleW实现QueryStringBindable< DoubleW> {
public Double value = null;
@Override
public选项< DoubleW> bind(String key,Map< String,String []> data){
String [] vs = data.get(key);
if(vs!= null&&对比度> 0){
String v = vs [0];
value = Double.parseDouble(v);
return F.Some(this);
}
return F.None();
}
@Override
public String unbind(String key){
return key +=+ value;
}
@Override
public String javascriptUnbind(){
return value.toString();
}
}
然后可以使用它如下在您的应用程序中:
GET / foo controllers.Application.action(d:util.DoubleW)
public static Result action(DoubleW d){
...
}
I'm learning myself Play 2.0 (Java API used) and would like to have a double/float parameter (for location coordinates), something like http://myfooapp.com/events/find?latitude=25.123456&longitude=60.251253.
I can do this by getting the parameters as String and parsing them at controller etc but can I use automatic binding here?
Now, I first tried simply having one double value:
GET /events/foo controllers.Application.foo(doublevalue: Double)
with
public static Result foo(Double doublevalue) {
return ok(index.render("Foo:" + doublevalue));
}
What I got was "No QueryString binder found for type Double. Try to implement an implicit QueryStringBindable for this type."
Have I missed something already provided or do I have to make a custom QueryStringBindable that parses Double?
I found some instructions on making a custom string query string binder with Scala at http://julien.richard-foy.fr/blog/2012/04/09/how-to-implement-a-custom-pathbindable-with-play-2/
What I tried:
I implemented DoubleBinder at package binders:
import java.util.Map;
import play.libs.F.Option;
import play.mvc.QueryStringBindable;
public class DoubleBinder implements QueryStringBindable<Double>{
@Override
public Option<Double> bind(String key, Map<String, String[]> data) {
String[] value = data.get(key);
if(value == null || value.length == 0) {
return Option.None();
} else {
return Option.Some(Double.parseDouble(value[0]));
}
}
@Override
public String javascriptUnbind() {
// TODO Auto-generated method stub
return null;
}
@Override
public String unbind(String key) {
// TODO Auto-generated method stub
return null;
}
}
And tried to add it to project/Build.scala's main:
routesImport += "binders._"
but same result : "No QueryString binder found for type Double...."
- I also changed the routing signature to java.lang.Double but that didn't help either
- I also changed the DoubleBinder to implement play.api.mvc.QueryStringBindable (instead of play.mvc.QueryStringBindable) both with Double & java.lang.Double at the routing signature but no help still
Currently (in Play 2.0), Java binders only work with self-recursive types. That is, types looking like the following:
class Foo extends QueryStringBindable<Foo> {
…
}
So, if you want to define a binder for java.lang.Double
, which is an existing type of Java, you need to wrap it in a self-recursive type. For example:
package util;
public class DoubleW implements QueryStringBindable<DoubleW> {
public Double value = null;
@Override
public Option<DoubleW> bind(String key, Map<String, String[]> data) {
String[] vs = data.get(key);
if (vs != null && vs.length > 0) {
String v = vs[0];
value = Double.parseDouble(v);
return F.Some(this);
}
return F.None();
}
@Override
public String unbind(String key) {
return key + "=" + value;
}
@Override
public String javascriptUnbind() {
return value.toString();
}
}
Then you can use it as follows in your application:
GET /foo controllers.Application.action(d: util.DoubleW)
public static Result action(DoubleW d) {
…
}
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