Java类操作

示例

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public interface UserService {
}

public class UserServiceImpl implements UserService {
}
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@SpringBootTest
class DemoApplicationTests {

@Test
void contextLoads() {
UserServiceImpl userServiceImpl = new UserServiceImpl();

// 父类 isAssignableFrom 子类
System.out.println(UserService.class.isAssignableFrom(UserServiceImpl.class)); // true

// userServiceImpl是否是UserService实例
System.out.println(userServiceImpl instanceof UserService); // true

// UserService能否强转为
System.out.println(UserService.class.isInstance(userServiceImpl)); // true
}

}