Java获取泛型T的类型 T.class

直接上代码：

public interface CrudRepository<T> {

    Iterable<T> findAll();

}

public class BaseImpl <T> implements CrudRepository<T> {

    @Override
    public Iterable<T> findAll() {
        Class<T> c = getTClass();
        System.out.println(c);
        common(c);
        return null;
    }

    /**
     * 通用的方法使用泛型的class去干一些事情。
     *
     * @param c 泛型类
     */
    private void common(Class<T> c) {

    }

    /**
     * 获取 T.class
     */
    public Class<T> getTClass() {
        return (Class<T>) ((ParameterizedType) getClass().getGenericSuperclass()).getActualTypeArguments()[0];
    }
}

public class PhoneRepository extends BaseImpl<Phone> {

    public static class Phone {
        private static final long serialVersionUID = 1L;
        private String name;
        private Long price;
        private Long updateDate;

        public String getName() {
            return name;
        }

        public void setName(String name) {
            this.name = name;
        }

        public Long getPrice() {
            return price;
        }

        public void setPrice(Long price) {
            this.price = price;
        }

        public Long getUpdateDate() {
            return updateDate;
        }

        public void setUpdateDate(Long updateDate) {
            this.updateDate = updateDate;
        }
    }
}

public class Test {

    public static void main(String[] args) {
        PhoneRepository phoneRepository = new PhoneRepository();
        Iterable<Phone> phones = phoneRepository.findAll();
    }
}

结果：
class cn.zero.reflect.PhoneRepository$Phone

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工具类：

public class GenericsUtils {

    /**
     * 通过反射,获得定义Class时声明的父类的范型参数的类型.
     *
     * 如public BookManager extends Manager<Book>
     */
    public static Class getSuperClassGenericType(Class clazz) {
        return getSuperClassGenericType(clazz, 0);
    }

    /**
     * 通过反射,获得定义Class时声明的父类的范型参数的类型.
     *
     * 如public BookManager extends Manager<Book>, 返回Book
     */
    public static Class getSuperClassGenericType(Class clazz, int index) throws IndexOutOfBoundsException {
        Type genType = clazz.getGenericSuperclass();
        if (!(genType instanceof ParameterizedType)) {
            return Object.class;
        }
        Type[] params = ((ParameterizedType) genType).getActualTypeArguments();
        if (index >= params.length || index < 0) {
            return Object.class;
        }
        if (!(params[index] instanceof Class)) {
            return Object.class;
        }
        return (Class) params[index];
    }
}