If the superclass is a parameterized type, the {@code Type}
* object returned must accurately reflect the actual type
* parameters used in the source code. T
上文档DOC，如果父类是一个参数化类型，那么Type返回的是参数类型的真实类型
package entity; import java.lang.reflect.ParameterizedType;
import java.lang.reflect.Type; /**
* Created by Administrator on 2016/11/27 0027.
*/
public class BaseDaoImpl<T> implements BaseDao<T> { public BaseDaoImpl(){
Type type = getClass().getGenericSuperclass();
Type[] params = ((ParameterizedType)type).getActualTypeArguments();
System.out.println((Class<T>)params[0]);
} public T findByid(int id) {
return null;
}
}
package entity; /**
* Created by Administrator on 2016/11/27 0027.
*/
public class UserDaoImpl extends BaseDaoImpl<User> {
}
package entity; /**
* Created by Administrator on 2016/11/27 0027.
*/
public interface BaseDao<T> {
public T findByid(int id);
}
package entity; import org.junit.Test; /**
* Created by Administrator on 2016/11/27 0027.
*/
public class GenericTest {
@Test
public void testGeneric(){
UserDaoImpl baseDao = new UserDaoImpl();
//BaseDaoImpl<User> baseDao1 = new BaseDaoImpl<User>();
}
}
记录总结，只有继承的父类为参数化类型，此时反射的
ParameterizedType 才能拿到参数类型