泛型真实类型
把项目中的代码抽出父类,有时需要用泛型。如果此时涉及到hibernate等数据库操作,比如"select u from User u",那么User怎么怎么表示出来呢?以下是研究的代码:
父类:
import static org.junit.Assert.*; import java.lang.reflect.ParameterizedType; import java.lang.reflect.Type; import org.junit.Test; public class Father<T> { public Father() { // TODO Auto-generated constructor stub System.out.println(this.getClass());//class mypss.children System.out.println(this.getClass().getSuperclass());//mypss.Father System.out.println(this.getClass().getGenericSuperclass());//mypss.Father<java.lang.Long> 带上了泛型 ParameterizedType parameterizedType = (ParameterizedType) this.getClass().getGenericSuperclass(); Type[] actualTypes = parameterizedType.getActualTypeArguments(); System.out.println(actualTypes[0]);//class java.lang.Long 真实的泛型类型,Long Class<T> actualType = (Class<T>) actualTypes[0]; System.out.println(actualType); } }
子类:
package mypss; import static org.junit.Assert.*; import org.junit.Test; public class children extends Father<Long> { @Test public void testde() throws Exception { System.out.println("子类"); } }