Spring if there are multiple implementations of the Service class, how do you know which category ServiceImpl the injection?

1. Each service impl can specify the name (using @Service ( "name"))

When injected into the service of 2.Controller use the name to specify which one injection.

　　(1).

　　@Autowired
   @Qualifier("名称")　

　　(2).

　　@Resource (name = " name" )

 

code show as below:

interface

public interface HumanService {
    public String name();
}

Interface implementation class 

@Service("teacherService")
public class TeacherServiceImpl implements HumanService {
    @Override
    public String name() {
        System.out.println("teacher");
        return "teacher";
    }
}

@Service("doctorService")
public class DoctorServiceImpl implements HumanService {
    @Override
    public String name() {
        System.out.println("doctor");
        return "doctor";
    }
}

Controller 

@RestController
public class HumanController {
//    @Resource(name="doctorService")

    @Autowired
    @Qualifier("teacherService")
    private HumanService humanService;

    @RequestMapping("/name")
    public String name(){
        return humanService.name();
    }
}