近期在捯饬spring的注解，现将遇到的问题记录下来，以供遇到同样问题的童鞋解决~
先说明下场景,代码如下：
有如下接口：
<pre>
public
interface
EmployeeService {
public
EmployeeDto getEmployeeById(Long id);
}
</pre>
同时有下述两个实现类 EmployeeServiceImpl和EmployeeServiceImpl1：
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<pre>
@Service("service")
public
class
EmployeeServiceImpl
implements
EmployeeService {
public
EmployeeDto getEmployeeById(Long id) {
return
new
EmployeeDto();
}
}
@Service("service1")
public
class
EmployeeServiceImpl1
implements
EmployeeService {
public
EmployeeDto getEmployeeById(Long id) {
return
new
EmployeeDto();
}
}
</pre>
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调用代码如下：
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<pre>
@Controller
@RequestMapping(
"/emplayee.do"
)
public
class
EmployeeInfoControl {
@Autowired
EmployeeService employeeService;
@RequestMapping(params
= "method=showEmplayeeInfo"
)
public
void
showEmplayeeInfo(HttpServletRequest request, HttpServletResponse response, EmployeeDto dto) {
#略
}
}
</pre>
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在启动tomcat时报如下错误：
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<pre>
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'employeeInfoControl': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: com.test.service.EmployeeService com.test.controller.EmployeeInfoControl.employeeService; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No unique bean of type [com.test.service.EmployeeService] is defined: expected single matching bean but found 2: [service1, service2]
</pre>
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其实报错信息已经说得很明确了,在autoware时，由于有两个类实现了EmployeeService接口，所以Spring不知道应该绑定哪个实现类，所以抛出了如上错误。
这个时候就要用到@Qualifier注解了，qualifier的意思是合格者，通过这个标示，表明了哪个实现类才是我们所需要的，我们修改调用代码，添加@Qualifier注解，需要注意的是@Qualifier的参数名称必须为我们之前定义@Service注解的名称之一！
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<pre>
@Controller
@RequestMapping(
"/emplayee.do"
)
public
class
EmployeeInfoControl {
@Autowired
**@Qualifier(**
"service"
)
EmployeeService employeeService;
@RequestMapping(params
= "method=showEmplayeeInfo"
)
public
void
showEmplayeeInfo(HttpServletRequest request, HttpServletResponse response, EmployeeDto dto) {
#略
}
}
</pre>
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