@Component
public interface Aorder {
    void say();
}

@Component
public class Corder  implements Aorder{
    @Override
    public void say() {
        System.out.println("----------Corder------------");
    }
}

@Component
public class Dorder implements Aorder{
    @Override
    public void say() {
        System.out.println("----------Border------------");
    }
}

@RunWith(SpringRunner.class)
@SpringBootTest(classes = Application.class)
public class OrderTest {
    @Autowired
    private MyOrderTest myOrderTest;

    @Test
    public void say(){
        myOrderTest.test();
    }
}

 此时会报错，调用Aorder时不知道调用哪一个bean

@Resource

@Service
public class MyOrderTest {
    @Resource(type = Corder.class)
    private Aorder aorder;

    public void test(){
        aorder.say();
    }
}

此时就能正常调用了，但是Corder,Dorder都实现Aorder，此时Corder，Dorder 都生成了bean

@Primary

@Component
@Primary
public class Corder  implements Aorder{
    @Override
    public void say() {
        System.out.println("----------Corder------------");
    }
}

Corder,Dorder都实现Aorder，此时只有Corder会生成bean,Dorder不会生成bean