问题描述:
项目中需要配置多个视图解析器,所以使用ContentNegotiatingViewResolver来处理,在其内部设置了FreeMarkerViewResolver 、InternalResourceViewResolver两个视图解析器,同时还有一个默认的defaultViews。
在测试类中,想要获取InternalResourceViewResolver类,会报错说没有定义InternalResourceViewResolver这个bean,找不到。
直接上图上代码:
applicationContext.xml:
<bean id="contentViewResolver" class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">
<property name="viewResolvers">
<list>
<bean
class="org.springframework.web.servlet.view.freemarker.FreeMarkerViewResolver">
<property name="order" value="1" />
<property name="requestContextAttribute" value="request" />
<property name="cache" value="false" />
<property name="prefix" value="" />
<property name="suffix" value=".ftl" />
<property name="contentType" value="text/html; charset=utf-8" />
</bean> <bean id="viewResolver"
class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<property name="prefix" value="/" />
<property name="suffix" value=".jsp" />
<property name="order" value="2"/>
</bean>
</list>
</property>
<property name="defaultViews">
<list>
<bean
class="org.springframework.web.servlet.view.json.MappingJackson2JsonView">
</bean>
</list>
</property>
</bean>
测试类:
String conf = "applicationContext.xml";
ApplicationContext ctx = new ClassPathXmlApplicationContext(conf); InternalResourceViewResolver inter = ctx.getBean(InternalResourceViewResolver.class);
System.out.println("inter: " + inter);
报错信息:
Exception in thread "main" org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type 'org.springframework.web.servlet.view.InternalResourceViewResolver' available
at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBean(DefaultListableBeanFactory.java:353)
at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBean(DefaultListableBeanFactory.java:340)
at org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1090)
at com.quanwc.blog.controller.UserController.main(UserController.java:39)
原因分析:
ContentNegotiatingViewResolver content = ctx.getBean(ContentNegotiatingViewResolver.class);
System.out.println("content: " + content); //可以获取到ContentNegotiatingViewResolver这个bean InternalResourceViewResolver inter = ctx.getBean(InternalResourceViewResolver.class);
System.out.println("inter: " + inter); //报错,无法获取到InternalResourceViewResolver这个bean
结果:
外部的ContentNegotiatingViewResolver bean可以获取到,但是其内部的InternalResourceViewResolver却无法获取到
原因:
spring在创建ContentNegotiatingViewResolver 的时候,会将InternalResourceViewResolver创建出来,并注入给viewResolvers这个属性; 在这个过程中spring并没有将创建出的InternalResourceViewResolver这个bean对象保存一份到自己的容器中。
也就说说,id为viewResolver的bean只服务于Id为contentViewResolver的这个bean。
我们可以将 InternalResourceViewResolver声明在外部的一个bean中,在ContentNegotiatingViewResolver 内部使用ref对其进行引用: <ref bean="viewResolver2"/>
参考链接:http://blog.sina.com.cn/s/blog_635675db01018miz.html