spring 注入失败报错

报错代码片段：

Error creating bean with name 'itemServiceImpl': Injection of autowired dependencies failed; 
nested exception is org.springframework.beans.factory.BeanCreationException:
 Could not autowire field: private com.taotao.search.mapper.ItemMapper com.taotao.search.service.ItemServiceImpl.itemMapper;
 nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: 
 No qualifying bean of type [com.taotao.search.mapper.ItemMapper] 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)}

 网上的方法都试过了，注解加了，mapper.xml的namespace什么的也检查了好几遍，都找不到错。

因为项目里放了一个*.*.mapper包和*.*.dao包，一度以为这两个包可能有冲突，仔细想想应该也不是这个原因。

经过再三的检查，偶然发现applicationContext-dao的配置文件里没有扫描mapper的包。添上之后问题解决。

附上工程目录和配置文件：

 

applicationContext-dao.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p"
	xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
	http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
	http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
	http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.0.xsd">

	<!-- 数据库连接池 -->
	<!-- 加载配置文件 -->
	<context:property-placeholder location="classpath:properties/*.properties" />
	<!-- 数据库连接池 -->
	<bean id="dataSource" class="com.alibaba.druid.pool.DruidDataSource"
		destroy-method="close">
		<property name="url" value="${jdbc.url}" />
		<property name="username" value="${jdbc.username}" />
		<property name="password" value="${jdbc.password}" />
		<property name="driverClassName" value="${jdbc.driver}" />
		<property name="maxActive" value="10" />
		<property name="minIdle" value="5" />
	</bean>
	<!-- 让spring管理sqlsessionfactory 使用mybatis和spring整合包中的 -->
	<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
		<!-- 数据库连接池 -->
		<property name="dataSource" ref="dataSource" />
		<!-- 加载mybatis的全局配置文件 -->
		<property name="configLocation" value="classpath:mybatis/SqlMapConfig.xml" />
	</bean>
	<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
		<!-- 给出需要扫描Dao接口包 -->
		<property name="basePackage" value="com.taotao.dao,com.taotao.search.dao,com.taotao.search.mapper" />
	</bean>
</beans>

注意配置文件里的最后一个<bean>,里面配置上扫描dao包和mapper包

<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
        <!-- 给出需要扫描Dao接口包 -->
        <property name="basePackage" value="com.taotao.dao,com.taotao.search.dao,com.taotao.search.mapper" />
</bean>

applicationContent-service.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:context="http://www.springframework.org/schema/context" xmlns:p="http://www.springframework.org/schema/p"
	xmlns:aop="http://www.springframework.org/schema/aop" xmlns:tx="http://www.springframework.org/schema/tx"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
	http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-4.0.xsd
	http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop-4.0.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
	http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-4.0.xsd">

	<!-- 包扫描器，扫描带@Service注解的类,此处加逗号分开，写成com.taotao.search.*会把controller扫描进来，引发父子容器问题 -->
	<context:component-scan base-package="com.taotao.search.service"></context:component-scan>
	<!-- 单机版solr客户端 , 在这配置完成后就可以直接让spring注入了 SolrServer是个抽象类，httpSolrServerhe clientSolrServer是其子类，一个是单机版，一个是集群版-->
	<bean id="httpSolrServer" class="org.apache.solr.client.solrj.impl.HttpSolrServer">
 		<constructor-arg name="baseURL" value="http://144.34.134.37:8080/solr"></constructor-arg>
	</bean>
</beans>

注意配置文件里包扫描器中扫描service包。

<!-- 包扫描器，扫描带@Service注解的类,此处加逗号分开，写成com.taotao.search.*会把controller扫描进来，引发父子容器问题 -->
    <context:component-scan base-package="com.taotao.search.service"></context:component-scan>

springmvc.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:p="http://www.springframework.org/schema/p"
	xmlns:context="http://www.springframework.org/schema/context"
	xmlns:mvc="http://www.springframework.org/schema/mvc"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">
    
    <!-- 配置包扫描器 -->    
    <context:component-scan base-package="com.taotao.search.controller"></context:component-scan>
    <!-- 配置注解驱动 -->
    <mvc:annotation-driven/>
</beans>        

这个配置文件是配置controller包的扫描，因为父子容器的关系，controller包的扫描要和dao包、service包的扫描分开。

web.xml

最后是web.xml。配置spring扫描上面dao包、service包的配置文件。配置springmvc扫描上面controller包的配置文件。

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
	id="taotao" version="2.5">
	<display-name>taotao-search</display-name>
	<welcome-file-list>
		<welcome-file>index.html</welcome-file>
		<welcome-file>index.htm</welcome-file>
		<welcome-file>index.jsp</welcome-file>
		<welcome-file>default.html</welcome-file>
		<welcome-file>default.htm</welcome-file>
		<welcome-file>default.jsp</welcome-file>
	</welcome-file-list>
	
	<!-- 加载spring容器 -->
	<context-param>
		<param-name>contextConfigLocation</param-name>
		<param-value>classpath:spring/applicationContext-*.xml</param-value>
	</context-param>
	<listener>
		<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
	</listener>

	<!-- 解决post乱码 -->
	<filter>
		<filter-name>CharacterEncodingFilter</filter-name>
		<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
		<init-param>
			<param-name>encoding</param-name>
			<param-value>utf-8</param-value>
		</init-param>
		<!-- <init-param>
			<param-name>forceEncoding</param-name>
			<param-value>true</param-value>
		</init-param> -->
	</filter>
	<filter-mapping>
		<filter-name>CharacterEncodingFilter</filter-name>
		<url-pattern>*</url-pattern>
	</filter-mapping>


	<!-- springmvc的前端控制器 -->
	<servlet>
		<servlet-name>taotao-search</servlet-name>
		<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
		<!-- contextConfigLocation不是必须的， 如果不配置contextConfigLocation， springmvc的配置文件默认在：WEB-INF/servlet的name+"-servlet.xml" -->
		<init-param>
			<param-name>contextConfigLocation</param-name>
			<param-value>classpath:spring/springmvc.xml</param-value>
		</init-param>
		<load-on-startup>1</load-on-startup>
	</servlet>
	<servlet-mapping>
		<servlet-name>taotao-search</servlet-name>
		<url-pattern>/search/*</url-pattern>
	</servlet-mapping>
	<!-- log4j配置文件位置 -->
	<context-param>
	    <param-name>log4jConfigLocation</param-name>
	    <param-value>classpath:log4j.properties</param-value>
	</context-param>
	
	<!-- 利用spring来使用log4j -->
	<listener>
	    <listener-class>org.springframework.web.util.Log4jConfigListener</listener-class>
	</listener>
</web-app>

总结：

*dao.xml文件配置数据库连接层的包扫描。一般是*.*.dao或*.*.mapper，多个包时用“，”分隔。

*service.xml文件配置服务层的包的扫描。一般是*.*.service包，多个时用“，”分隔。

springmvc.xml文件配置视图层的包的扫描。一般是*.*.controller包。

springmvc.xml为什么不用*.controller命名？

可能是因为springmvc.xml属于springmvc容器，dao.xml和service.xml属于spring容器吧！

web.xml文件则配置spring和springmvc分别扫描哪些配置文件