@Autowired对象在一个类中获取空值,而在另一个类中成功连接

Question

我正在使用Spring 3和Spring Security开发一个项目.我的问题是IoC容器.当我UserDetailsService为Spring Security-3 编写自己的实现时问题就出现了.我检查了其他问题,但仍无法解决问题.

问题的定义是:

我有两个单独的类(一个是UsersController.java扩展的@Controller,ProjectUserDetailsService哪个扩展@Service),它使用一个公共对象进行自动装配.但是当对象成功自动装入时UsersController,它就null在ProjectUserDetailsService类中,尽管这个类(ProjectUserDetailsService)的对象已成功创建(我通过调试验证了这一点).

有什么建议如何解决这个问题？

这里是我的web.xml,project-servlet.xml而且project-security.xml文件和相关的类.

Web.xml`

<?xml version="1.0" encoding="UTF-8"?>
<!--
  - Tutorial web application
  -
  -->
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" version="2.5">
  <display-name>Ecognitio with Spring Security</display-name>
  <context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>
            /WEB-INF/ecognitio-servlet.xml
            /WEB-INF/ecognitio-security.xml
        </param-value>
  </context-param>
  <context-param>
    <param-name>webAppRootKey</param-name>
    <param-value>tutorial.root</param-value>
  </context-param>
  <filter>
    <filter-name>springSecurityFilterChain</filter-name>
    <filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
  </filter>
  <filter-mapping>
    <filter-name>springSecurityFilterChain</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>
  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>
  <listener>
    <listener-class>org.springframework.security.web.session.HttpSessionEventPublisher</listener-class>
  </listener>
  <servlet>
    <servlet-name>ecognitio</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>project</servlet-name>
    <url-pattern>*.action</url-pattern>
  </servlet-mapping>
  <servlet-mapping>
    <servlet-name>project</servlet-name>
    <url-pattern>*.html</url-pattern>
  </servlet-mapping>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>

project-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:mvc="http://www.springframework.org/schema/mvc"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:p="http://www.springframework.org/schema/p"
    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
        http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-3.0.xsd">

    <!-- Scans the classpath of this application for @Components to deploy as beans -->
    <context:component-scan base-package="com.project" />

    <!-- Configures the @Controller programming model -->
    <mvc:annotation-driven />

     <bean  id="messageSource" 
            class="org.springframework.context.support.ResourceBundleMessageSource"
            p:basename="Messages"/>

  <!-- misc -->
<!--    <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="viewClass" value="org.springframework.web.servlet.view.JstlView"/>
        <property name="suffix" value=".jsp"/>
    </bean>  --> 


    <bean id="viewResolver"
        class="org.springframework.web.servlet.view.UrlBasedViewResolver">

       <property name="viewClass">
         <value>
              org.springframework.web.servlet.view.tiles2.TilesView
            </value>
        </property>
    </bean>

    <bean id="tilesConfigurer"
    class="org.springframework.web.servlet.view.tiles2.TilesConfigurer">
      <property name="definitions">
             <list>
                <value>/WEB-INF/tiles.xml</value>
             </list>
      </property>
    </bean>

    <!-- Configures Hibernate - Database Config -->
    <import resource="db-config.xml" />
</beans>

project-security.xml

<?xml version="1.0" encoding="UTF-8"?>

<!--
  - Sample namespace-based configuration
  -
  -->

<beans:beans xmlns="http://www.springframework.org/schema/security"
    xmlns:beans="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-3.0.xsd
                        http://www.springframework.org/schema/security http://www.springframework.org/schema/security/spring-security-3.1.xsd">

    <debug />

    <global-method-security pre-post-annotations="enabled">
        <!-- AspectJ pointcut expression that locates our "post" method and applies security that way
        <protect-pointcut expression="execution(* bigbank.*Service.post*(..))" access="ROLE_TELLER"/>
        -->
    </global-method-security>

    <http pattern="/loggedout.jsp" security="none"/>

    <http use-expressions="true" >
        <intercept-url pattern="/secure/extreme/**" access="hasRole('ROLE_SUPERVISOR')"/>
        <intercept-url pattern="/secure/**" access="isAuthenticated()" />

        <!--
             Allow all other requests. In a real application you should
             adopt a whitelisting approach where access is not allowed by default
          -->
        <intercept-url pattern="/login.jsp*" access="isAuthenticated()==false"/>
        <intercept-url pattern="/timeout.jsp*" access="isAuthenticated()==false"/>
        <intercept-url pattern="/**" access="hasRole('ROLE_USER')" />

       <!-- <intercept-url pattern="/**" access="permitAll" /> --> 
        <form-login login-page="/login.jsp" authentication-failure-url="/login.jsp?login_error=1" default-target-url="/dashboard.html" />
        <logout logout-success-url="/login.jsp" delete-cookies="JSESSIONID"/>
        <remember-me />
<!--
    Uncomment to enable X509 client authentication support
        <x509 />
-->
        <!-- Uncomment to limit the number of sessions a user can have 
        <session-management invalid-session-url="/login.jsp">
            <concurrency-control max-sessions="1" error-if-maximum-exceeded="true" />
        </session-management>
        -->

    </http>

            <!-- HERE IS WHERE I USE an object of ProjectUserDetailsService -->
    <authentication-manager>
         <authentication-provider user-service-ref="userDetailsService" />   
    </authentication-manager>


 <!--  

</beans:beans>

UsersController.java (此类的UsersDAO类对象的自动装配成功)

package com.project.users;

//required imports



@Controller
public class UsersControllers
{

@Autowired
private UsersDAO usersDAO;

    //Some more autowires and some class specific code


}

ProjectUserDetailsService.java (UsersDAO自动装配不起作用)

package com.project.security;

import java.util.ArrayList;
import java.util.Collection;

//required imports


@SuppressWarnings("deprecation")
@Service("userDetailsService") 
public class ProjectUserDetailsService implements UserDetailsService {

   @Autowired
   private UsersDAO usersDAO;
  @Autowired private Assembler assembler;

  @Transactional(readOnly = true)
  public UserDetails loadUserByUsername(String username)
      throws UsernameNotFoundException, DataAccessException {

    UserDetails userDetails = null;
    //For debugging purposes
    if(usersDAO==null){
        System.out.println("DAO IS NULL");
        System.out.println("DAO IS NULL");
        System.out.println("DAO IS NULL");

    }
    User userEntity = usersDAO.findUserbyEmail("'"+username+"'");


    if (userEntity == null)
      throw new UsernameNotFoundException("user not found");

    return assembler.buildUserFromUserEntity(userEntity);

  }
}

Answer 1

由于第二个 bean 不在指定的 bean 注释包组件扫描中，如下所示project-servlet.xml：

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

它不认为它是一项服务，也不翻译注释。

您需要进一步扩展它或将其移动到以 com.project 开头的包中，或者像这样：

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