Spring，SpringMvc配置常见的坑，注解的使用注意事项，applicationContext.xml和spring.mvc.xml配置注意事项，spring中的事务失效，事务不回滚原因
1、Spring中的applicationContext.xml配置错误导致的异常
异常信息：
org.apache.ibatis.binding.BindingException: Invalid bound statement (not found): com.ssm.service.BTestService.getPhoneKey
at org.apache.ibatis.binding.MapperMethod$SqlCommand.<init>(MapperMethod.java:223)
at org.apache.ibatis.binding.MapperMethod.<init>(MapperMethod.java:48)
at org.apache.ibatis.binding.MapperProxy.cachedMapperMethod(MapperProxy.java:59)
at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:52)
at com.sun.proxy.$Proxy17.getPhoneKey(Unknown Source)
如果是service接口调用出现此错误信息，注意这里不是myabtis接口mapper.java调用出现了此错误
导致异常的错误配置如下：
注意不要配置成 com.ssm.dao.* 这种配置方式扫描的是dao下的子包，最好配置为精准扫描包
为什么 说这里被mybatis重复扫描了呢？如图所示这里的 service在debug下查看是org.apache.ibatis.binding.MapperProxy@******
如果配置扫描是这种com.ssm.dao.*，会报如下错误
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.ssm.dao.AppUserPhonekeyMapper com.ssm.service.BTestServiceImpl.appUserPhonekeyMapper; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [com.ssm.dao.AppUserPhonekeyMapper] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:531)
at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88)
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor.postProcessPropertyValues(AutowiredAnnotationBeanPostProcessor.java:295)
2、以为是Spring中bean命名导致的错误
异常信息如下：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'beanTestController': Injection of autowired dependencies failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.ssm.service.TBestService com.ssm.controller.BeanTestController.tBestService; nested exception is org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type [com.ssm.service.TBestService] is defined: expected single matching bean but found 2: TBestServiceImpl,TBestService
Caused by: org.springframework.beans.factory.BeanCreationException: Could not autowire field: private com.ssm.service.TBestService com.ssm.controller.BeanTestController.tBestService; nested exception is org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type [com.ssm.service.TBestService] is defined: expected single matching bean but found 2: TBestServiceImpl,TBestService
at org.springframework.beans.factory.annotation.AutowiredAnnotationBeanPostProcessor$AutowiredFieldElement.inject(AutowiredAnnotationBeanPostProcessor.java:531)
Caused by: org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type [com.ssm.service.TBestService] is defined: expected single matching bean but found 2: TBestServiceImpl,TBestService
配置如下：
这里的spring核心配置文件中的mybatis扫描配置还是最大范围的，包含了service接口，这里controller中配置如下
注意：上面的异常是不能找到注入的名称，命名规则如下（myabtis应该是这样的！，spring中@Autowired注入名称正常是任意的命名），如果controller写成了
private TBestService TBestService 这种写法启动不报错，但是这时候的TBestService 在DEBUG模式下查看还是第一种里面的MapperProxy ，运行时还是会报第一种错
3、Spring @Autowired注入名称正常是任意的命名，测试如下：
spring自动对应找到了，service接口的实现类
有人可能怀疑是 注解的问题@Autowired 和@Resource不一样，测试过，是一样的！！具体这两个注解的区别大家可以参考 :
https://www.cnblogs.com/smileLuckBoy/p/5801678.html
4、补充一下原来遇到的坑：Spring中的事务失效，事务不回滚原因
正常情况就是注解扫描的问题，
原来失效情况是这样的：
spring中的applicationContext.xml中的扫描
<context:component-scan base-package="com.ssm.*">
<context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller" />
</context:component-scan>
这里扫描了service接口以及实现，但是springmvc扫描又把service接口和实现扫描了一遍，导致了springmvc接管了service接口，正常的访问和其他操作都没问题，当需要事务回滚就不好用了。
总结： 在这里建议大家在spring xml文件配置中需要注意扫描的范围.
1、spring负责扫描全局范围的注解
2、mybatis注解扫描 dao的包
3、springmvc需要扫描 controller
千万不要扩大范围，很容易带来一些费解的错误.
