class A<T,S> {
    //獲取S的class
    public Class<T> poClass = (Class<T>) (((ParameterizedType) this.getClass().getGenericSuperclass())).getActualTypeArguments()[1];

    /**
     * 獲取po物件
     * @return
     */
    public  T getPo() {
        T t = null;
        try {
            t =  poClass.newInstance();
        } catch (InstantiationException e) {
            e.printStackTrace();
        } catch (IllegalAccessException e) {
            e.printStackTrace();
        }
        return t;
    }

}
class B extends A<String,Integer> {

}
public class Generic {



    public static void main(String[] args) {
        //輸出class java.lang.Integer
        System.out.println( new B().poClass);

    }

}