通用 DAO 类的通用测试类？

Question

我正在尝试测试一些从通用 DAO 继承的 DAO 类，并且想知道是否有一种方法可以编写一个通用测试类来测试我的通用 DAO 的功能，并创建从它继承的其他测试类

我的通用 DAO类：

 public abstract class GenericDAO<T> {
    private final Class<T> entityClass;

    public GenericDAO(Class<T> entityClass) {
        this.entityClass = entityClass;
    }
    //bunch of methods
    //...
}

一个示例 DAO，继承自我

public class OptionsDAO extends GenericDAO<Options> {

    public OptionsDAO() {
        super(Options.class);
    }
}

当前测试中的通用 DAO，

public class OptionsDAOTest {
    //...
    @Test
    public void testSomeMethod() {
        OptionsDAO odao = new OptionsDAO(); //this is what blocked me from achieving what i'm trying to do (look @next sction)
    odao.callSomeMethod();
    //Asserts and what not...
    }
    //...
}

这就是我希望做的

public class GenericDAOTest<T> {

    private final Class<T> entityClass;

    public GenericDAOTest(Class<T> entityClass) {
        this.entityClass = entityClass;
    }
    @Test
    public void testSomeMethod() {
        GenericDAO gdao = ???//how can i get an instance based on the T passed to the class?
    odao.callSomeMethod();
    //Asserts and what not...
    }
    //...
}

public class OptionsDAOTest extends GnericDAOTest<Options> {
    public OptionsDAOTest() {
        super(OptionsDAO.class);
    }    
    //how can i call inhrited methods here to test them on an Options java bean
    //and do the same with oter DAO classes i have?
}

Answer 1

GenericDAO gdao = ???//我如何根据传递给类的 T 获取实例？

如果泛型类提供无参数构造函数，您只需调用 entityClass.newInstance() 即可。
请注意，entityClass 的类型为 Class 类型，因此属于 T 类型。