传递泛型Class <T>作为参数

Question

我需要传递一个Class作为参数,但我只有通用类型T.我如何推断泛型类并将其传递给fromJson()？

public class Deserializer<T> implements JsonDeserializer<JsonList<T>> {
    public T someMethod(){
        ...
        T tag = gson.fromJson(obj, ???); // takes a class e.g. something.class
        ...
    }                       
}

谢谢

Answer 1

感谢Java Type Erasure,你不能.

http://docs.oracle.com/javase/tutorial/java/generics/erasure.html

Answer 2

假设Deserializer是您的类，执行此操作的典型方法是将Class作为构造函数参数：

public class Deserializer<T> implements JsonDeserializer<JsonList<T>> {

  public static <T> Deserializer<T> newInstance(Class<T> c) {
    return new Deserializer<T>(c);
  }

  private final Class<T> clazz;
  private Deserializer(Class<T> c) { this.clazz = c; }

  public T someMethod(){
    ...
    T tag = gson.fromJson(obj, clazz); // takes a class e.g. something.class
    ...
  }                       
}

然后在客户端代码中：

Deserializer<String> d = Deserializer.newInstance(String.class);