SSM整合报错

在ssm整合中遇到的找不到bean的异常，记录一下。

在项目部署到Tomcat中后启动报错：Error creating bean with name 'XXXController': Unsatisfied dependency expressed through field 'XXXService';

或：No qualifying bean of type 'com.xx.service.XXXService' available: expected at least 1 bean which qualifies as autowire candidate. 

当使用Junit4对Spring框架进行测试（不包含SpringMVC）时，增删改查均无问题，唯独在加上SpringMVC配置时才会报这两个错误，

排除漏加注解和jar冲突后找到问题，出于web.xml

原有web.xml配置：

<welcome-file-list>
<welcome-file>index.jsp</welcome-file> 
</welcome-file-list>

<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:applicationContext.xml</param-value>
</context-param>

<servlet>
<servlet-name>springDispatcherServlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:springmvc.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>

<filter>
<filter-name>encodingFilter</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>


<servlet-mapping>
<servlet-name>springDispatcherServlet</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>

<filter-mapping>
<filter-name>encodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

修改后的配置，增加了ContextLoaderListener：

<welcome-file-list>
<welcome-file>index.jsp</welcome-file> 
</welcome-file-list>

<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:applicationContext.xml</param-value>
</context-param>
<listener>
<!-- 通过listener的方式启动spring容器 -->
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>

<servlet>
<servlet-name>springDispatcherServlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:springmvc.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
</servlet>

<filter>
<filter-name>encodingFilter</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>


<servlet-mapping>
<servlet-name>springDispatcherServlet</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>

<filter-mapping>
<filter-name>encodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

问题解决。

另一种解决方式是在web.xml中的DispatcherServlet局部变量中加入对applicationContext.xml的引用

引起异常的原因出于web.xml中个组件的加载顺序。