遇见Error creating bean with name '控制器名字'的错误的时候怎么办

遇见这种问题，八成的可能性是找不到业务实现层，通过在业务实现层查找是否添加@Service注解。

Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException:
 Error creating bean with name 'userController': Unsatisfied dependency expressed through field 'userService';
 nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: 
 No qualifying bean of type 'com.boron.service.UserService' available: expected at least 1 bean which qualifies as autowire candidate. 
Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

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原因：service层没有加注解
在搭spring mvc框架时，ide不会报错但会有编译错误的几个注意事项：
1.controller 加注解

@RestController
@RequestMapping("/user")

2.service加注解

@Service
@Autowired

3.dao 加注解和实现接口
@Param("")