Spring MVC中的依赖注入

Question

I would like to initialize my MessageSource field with Dependency Injection in Spring. This is what have so far:

package com.ucmas.cms.view;

@Component
public class PdfRevenueReportView extends AbstractPdfView {
  ...
  @Autowired
  private MessageSource messageSource;
  ...
}

mvc-dispatcher-servlet.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans:beans xmlns="sec://www.springframework.org/schema/mvc"
    xmlns:beans="http://www.springframework.org/schema/beans" xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.1.xsd
        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/security http://www.springframework.org/schema/security/spring-security-3.1.xsd">

    <context:component-scan base-package="com.ucmas.cms.controller,com.ucmas.cms.view" />

    <!-- Enables the Spring MVC @Controller programming model -->
    <mvc:annotation-driven />
    ...
    <beans:bean class="org.springframework.web.servlet.view.XmlViewResolver">
       <beans:property name="location" value="/WEB-INF/spring-pdf-views.xml" />
       <beans:property name="order" value="0" />
    </beans:bean>

</beans:beans>

I have defined my messageSource in root-context.xml

<bean id="messageSource"    

class="org.springframework.context.support.ReloadableResourceBundleMessageSource">
        <property name="basename" value="classpath:messages" />
        <property name="defaultEncoding" value="UTF-8" />
    </bean>

My controller classes work fine, however I am unable to inject the messageSource field in the PdfRevenueReportView class. What should I do to make the DI works ?

UPDATED

I define the view in xml as follow

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    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-3.1.xsd">
    <bean id="PdfRevenueSummary" class="com.ucmas.cms.view.PdfRevenueReportView" />
</beans>

Perhaps this is why the messageSource is always null ?

Answer 1

I got it working by updating my spring-pdf-views.xml into

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    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-3.1.xsd">
    <bean id="PdfRevenueSummary" class="com.ucmas.cms.view.PdfRevenueReportView">
        <property name="messageSource" ref="messageSource"/>
    </bean>
</beans>

However this requires me to generate setter and getter for messageSource field and removing the @Autowired annotation.

Answer 2

In your dispatcher servlets configuration you need to create a bean for the message source.

<bean id="messageSource"
    class="org.springframework.context.support.ResourceBundleMessageSource">
    <property name="basename" value="directory/with/messagesource"/>
</bean>

Also ensure that the messages directory is on the classpath.

Answer 3

You are annotating messageSource with Autowired. This might not work when your bean messageSource whilst is an interface of MessageResource, is really the implementation ResourceBundleMessageSource .

I think your DI would have worked if you used @Resource instead as it is name based:

@Resource
private MessageSource messageSource;