springmvc+mybatis 到注入失败的一种原因及解决方案

今天在整合spring和mybatis时出现No qualifying bean of type [com.studyplan.dao.UserDao] found for dependency，dao无法注入问题，web.xml文件如下

<!DOCTYPE web-app PUBLIC

"-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"

"http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>

<display-name>Archetype Created Web Application</display-name>

<!-- Spring和mybatis的配置文件 -->

<context-param>

<param-name>contextConfigLocation</param-name>

<param-value>/WEB-INF/configs/spring/spring-mybatis.xml</param-value>

</context-param>

<servlet>

<servlet-name>mvc-dispatcher</servlet-name>

<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>

<init-param>

<param-name>contextConfigLocation</param-name>

<param-value>/WEB-INF/configs/spring/mvc-dispatcher-servlet.xml</param-value>

</init-param>

<load-on-startup>1</load-on-startup>

</servlet>

<servlet-mapping>

<servlet-name>mvc-dispatcher</servlet-name>

<url-pattern>/</url-pattern>

</servlet-mapping>

</web-app>

因为mvc-dispatcher-servlet.xml为<load-on-startup>1</load-on-startup>所以该servlet的执行顺序较高，spring-mybatis.xml的执行顺序较低，spring-mybatis.xml和mvc-dispatcher-servlet.xml的内容如下

mvc-dispatcher-servlet.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: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/context

http://www.springframework.org/schema/context/spring-context.xsd

http://www.springframework.org/schema/mvc

http://www.springframework.org/schema/mvc/spring-mvc.xsd"

>

<context:annotation-config />

<!-- 自动扫描 -->

<context:component-scan base-package="com.studyplan" />

<!--

<context:component-scan base-package="com.studyplan.controller">

<context:include-filter type="annotation" expression="org.springframework.stereotype.Controller"/>

</context:component-scan>

<context:component-scan base-package="com.studyplan.service">

<context:include-filter type="annotation" expression="org.springframework.stereotype.Service"/>

</context:component-scan>

-->

<mvc:annotation-driven />

<bean class="org.springframework.web.servlet.view.InternalResourceViewResolver">

<property name="prefix" value="/views/" />

<property name="suffix" value=".jsp" />

</bean>

</beans>

spring-mybatis.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-3.1.xsd

http://www.springframework.org/schema/context

http://www.springframework.org/schema/context/spring-context-3.1.xsd

http://www.springframework.org/schema/mvc

http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd">

<!-- 自动扫描 -->

<context:component-scan base-package="com.studyplan.dao" />

<!-- 引入配置文件 -->

<bean id="propertyConfigurer"

class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">

<property name="location" value="classpath:jdbc.properties" />

</bean>

<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource"

destroy-method="close">

<property name="driverClassName" value="${driver}" />

<property name="url" value="${url}" />

<property name="username" value="${username}" />

<property name="password" value="${password}" />

<!-- 初始化连接大小 -->

<property name="initialSize" value="${initialSize}"></property>

<!-- 连接池最大数量 -->

<property name="maxActive" value="${maxActive}"></property>

<!-- 连接池最大空闲 -->

<property name="maxIdle" value="${maxIdle}"></property>

<!-- 连接池最小空闲 -->

<property name="minIdle" value="${minIdle}"></property>

<!-- 获取连接最大等待时间 -->

<property name="maxWait" value="${maxWait}"></property>

</bean>

<!-- spring和MyBatis完美整合，不需要mybatis的配置映射文件 -->

<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">

<property name="dataSource" ref="dataSource" />

<!-- 自动扫描mapping.xml文件 -->

<property name="mapperLocations" value="classpath*:com/studyplan/mapping/*.xml"></property>

</bean>

<!-- DAO接口所在包名，Spring会自动查找其下的类 -->

<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">

<property name="basePackage" value="com.studyplan.dao" />

<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property>

</bean>

<!-- (事务管理)transaction manager, use JtaTransactionManager for global tx -->

<bean id="transactionManager"

class="org.springframework.jdbc.datasource.DataSourceTransactionManager">

<property name="dataSource" ref="dataSource" />

</bean>

</beans>

spring-mybatis.xml中定义的有关于dao的定义，但是由于他的优先级较低，所以在spring进行注入的时候并没有读取这个xml文件，导致了dao层无法注入

解决方案如下

将spring-mybatis.xml更名为mvc-spring-mybatis.xml，将web.xml修改为一下的格式

<!DOCTYPE web-app PUBLIC

"-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"

"http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>

<display-name>Archetype Created Web Application</display-name>

<!-- Spring和mybatis的配置文件 -->

<servlet>

<servlet-name>mvc-dispatcher</servlet-name>

<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>

<init-param>

<param-name>contextConfigLocation</param-name>

<param-value>/WEB-INF/configs/spring/mvc*.xml</param-value>

</init-param>

<load-on-startup>1</load-on-startup>

</servlet>

<servlet-mapping>

<servlet-name>mvc-dispatcher</servlet-name>

<url-pattern>/</url-pattern>

</servlet-mapping>

</web-app>

这样这两个配置文件就会一起读进来