Spring的注解@Qualifier注解

@Qualifier注解了，qualifier的意思是合格者，通過這個標示，表明了哪個實現類才是我們所需要的，我們修改調用代碼，添加@Qualifier注解，需要注意的是@Qualifier的參數名稱必須為我們之前定義@Service注解的名稱之一！   例子：

@Service("a")
public class EmployeeServiceImpl implements EmployeeService {
    public EmployeeDto getEmployeeById(Long id) {
        return new EmployeeDto();
    }
}

@Service("b")
public class EmployeeServiceImpl1 implements EmployeeService {
    public EmployeeDto getEmployeeById(Long id) {
        return new EmployeeDto();
    }
}

@Controller
@RequestMapping("/emplayee.do")
public class EmployeeInfoControl {
    
    @Autowired
    @Qualifier("b")
    EmployeeService employeeService;
    
    @RequestMapping(params = "method=showEmplayeeInfo")
    public void showEmplayeeInfo(HttpServletRequest request, HttpServletResponse response, EmployeeDto dto) {
        #略
    }
}