我无法理解 Spring MVC。我有以下 web.xml ：
<web-app xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
version="3.0">
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/config/root-context.xml</param-value>
</context-param>
<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>
<servlet>
<servlet-name>RESTServlet</servlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
<init-param>
<param-name>contextConfigLocation</param-name>
<param-value>/WEB-INF/config/servlet-context.xml</param-value>
</init-param>
<load-on-startup>1</load-on-startup>
<async-supported>true</async-supported>
</servlet>
<servlet-mapping>
<servlet-name>RESTServlet</servlet-name>
<url-pattern>/</url-pattern>
</servlet-mapping>
</web-app>
在 root-context.xml 文件中，我声明了各种 bean，一些带有 xml，而另一些带有注释：
<?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"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd">
<!-- Root Context: defines shared resources visible to all other web components -->
<context:component-scan base-package="com.dynamease.**" />
<context:annotation-config />
<!-- Configures External Property Resolution -->
<import resource="properties.xml" />
<!-- Configures Shared Data Access Resources -->
<import resource="data.xml" />
<bean id="contextSource" class="org.springframework.ldap.core.support.LdapContextSource">
<property name="url" value="ldap://192.168.1.10:10389" />
<property name="base" value="dc=dynamease,dc=net" />
<property name="userDn" value="uid=admin,ou=system" />
<property name="password" value="secret" />
</bean>
<bean id="ldapTemplate" class="org.springframework.ldap.core.LdapTemplate">
<constructor-arg ref="contextSource" />
</bean>
</beans>
在 servlet-context.xml 中，我定义了与 Web 逻辑相关的 bean：
<?xml version="1.0" encoding="UTF-8"?>
<beans:beans xmlns="http://www.springframework.org/schema/mvc" xmlns:context="http://www.springframework.org/schema/context"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:beans="http://www.springframework.org/schema/beans"
xsi:schemaLocation="
http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-3.0.xsd">
<!-- DispatcherServlet Context: defines this servlet's request-processing
infrastructure -->
<!-- Enables the Spring MVC @Controller programming model -->
<annotation-driven />
<interceptors>
<beans:bean
class="com.dynamease.entity.springsocialentities.UserInterceptor">
<beans:constructor-arg ref="usersConnectionRepository" />
</beans:bean>
</interceptors>
<!-- Handles HTTP GET requests for /resources/** by efficiently serving
up static resources in the ${webappRoot}/resources directory -->
<resources mapping="/resources/**" location="/resources/" />
<!-- Resolves views selected for rendering by @Controllers to .jsp resources
in the /WEB-INF/views directory -->
<beans:bean
class="org.springframework.web.servlet.view.InternalResourceViewResolver">
<beans:property name="prefix" value="/WEB-INF/views/" />
<beans:property name="suffix" value=".jsp" />
</beans:bean>
<!-- Imports user-defined @Controller beans that process client requests -->
<bean class="com.dynamease.web.rest.HomeController">
<constructor-arg ref="facebook" />
</bean>
<!-- Allows users to sign-in with their provider accounts. -->
<bean class="org.springframework.social.connect.web.ProviderSignInController">
<constructor-arg ref="connectionFactoryLocator" />
<constructor-arg ref="usersConnectionRepository" />
<constructor-arg>
<bean class="com.dynamease.entity.springsocialentities.SimpleSignInAdapter" />
</constructor-arg>
</bean>
<mvc:view-controller path="/signin" />
<mvc:view-controller path="/signout" />
</beans:beans>
问题是 root-context.xml 中定义的 bean 没有初始化（我得到 Null 指针异常试图访问它们）。例如，在 HomeController bean 中：
@Autowired
private DynDirectoryServiceImpl dynDirectoryService;
@RequestMapping(value = "/", method = RequestMethod.GET)
public String home(Model model) {
System.out.println("<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<");
System.out.println(this.getClass().toString());
System.out.println(dynDirectoryService.toString());
}
最后一行失败。
这是 DynDirectoryServiceImpl 代码：
@Component
public class DynDirectoryServiceImpl implements DynDirectoryServiceInterface {
@Autowired
private LdapTemplate ldapTemplate;
@Autowired
private OdmManager odmManager;
@Override
public boolean verify(DynContact dynContact) {
// TODO Auto-generated method stub
return false;
}
}