@Autowired、@Resource的区别

@Autowired 这个是spring的注解    

org.springframework.beans.factory.annotation.Autowired

@Resource 这个是java自带的注解   

javax.annotation.Resource

@Autowired默认是按照类型来注入的，需要按名字注入的话可以跟@Qualifier搭配使用

@Resource是按照里面的name属性来注入的

针对于面向接口编程的话，一个接口一个实现类是没啥区分性的。

倘若两个实现类，你不指定的话，会报这个错

org.springframework.beans.factory.BeanCreationException bean创建失败

expected single matching bean but found 2: personServiceImpl1,personServiceImpl2

可以写一个实例 一个service接口，两个serviceImpl实现类

public interface PersonService {public List<Person> listPerson();
}

@Service
public class PersonServiceImpl1 implements PersonService{
    @Autowired
    private PersonMapper mapper;

    public List<Person> listPerson() {
        System.out.println("PersonServiceImpl1.java");
        return mapper.listPerson();
    }
}

@Service
public class PersonServiceImpl2 implements PersonService{
    @Autowired
    private PersonMapper mapper;

    public List<Person> listPerson() {
        System.out.println("PersonServiceImpl2.java");
        return mapper.listPerson();
    }
}

controller层来进行注入调用

@Controller
public class PersonController {
    @Autowired
    @Qualifier("personServiceImpl1")
    private PersonService service;
    
    @Resource(name="personServiceImpl2")
    private PersonService service2;
    
    @RequestMapping("listPerson")
    @ResponseBody
    public void listPerson(){
        List<Person> list = service.listPerson();
        System.out.println(list);
    }
    
    @RequestMapping("listPerson2")
    @ResponseBody
    public void listPerson2(){
        List<Person> list = service2.listPerson();
        System.out.println(list);
    }
}