java 如何获得通用接口的具体类型
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How to get concrete type of a generic interface
提问by bwawok
I have an interface
我有一个界面
public interface FooBar<T> { }
I have a class that implements it
我有一个实现它的类
public class BarFoo implements FooBar<Person> { }
public class BarFoo implements FooBar<Person> { }
With reflection, I want to take an instance of BarFoo and get that the version of FooBar it implements is Person.
通过反射，我想获取 BarFoo 的一个实例，并确定它实现的 FooBar 版本是 Person。
I use .getInterfacesfrom BarFoo to get back to FooBar, but that doesn't help me find out what T is.
我使用.getInterfacesfrom BarFoo 返回到 FooBar，但这并不能帮助我找出 T 是什么。
回答by BalusC
You can grab generic interfaces of a class by Class#getGenericInterfaces()which you then in turn check if it's a ParameterizedTypeand then grab the actual type argumentsaccordingly.
您可以获取类的泛型接口，Class#getGenericInterfaces()然后依次检查它是否为 a ParameterizedType，然后相应地获取实际的类型参数。
Type[] genericInterfaces = BarFoo.class.getGenericInterfaces();
for (Type genericInterface : genericInterfaces) {
if (genericInterface instanceof ParameterizedType) {
Type[] genericTypes = ((ParameterizedType) genericInterface).getActualTypeArguments();
for (Type genericType : genericTypes) {
System.out.println("Generic type: " + genericType);
}
}
}
回答by matt b
Try something like the following:
请尝试以下操作：
Class<T> thisClass = null;
Type type = getClass().getGenericSuperclass();
if (type instanceof ParameterizedType) {
ParameterizedType parameterizedType = (ParameterizedType) type;
Type[] typeArguments = parameterizedType.getActualTypeArguments();
thisClass = (Class<T>) typeArguments[0];
}
