Spring自定义用户详细信息服务空指针异常

时间：2013-05-25 15:33:59

标签： java spring spring-security

我用自定义用户详细信息服务编写了一个Spring MVC应用程序。

@Service("userDetailsService")
public class CustomUserDetailsService implements UserDetailsService{

    @Autowired
    private UserAccountDao userAccountDao;

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

        UserDetails user = null;
        try {

            UserAccount dbUser = (UserAccount) userAccountDao.getByUsername(username);

此时，userAccountDao为null，因此它在上面的行上抛出一个空指针异常，这意味着自动装配不会在此服务中注入此Dao。现在Dao本身已经自动装配...... 

@Repository("userAccountDao")
public class UserAccountDaoImpl extends UserDaoImpl implements UserAccountDao {

    @Autowired
    private PasswordEncoder passwordEncoder;

    @Autowired
    private SessionFactory sessionFactory;

    @Override
    public void addUserAccount(final UserAccount userAccount) {
        userAccount.setPassword(passwordEncoder.encodePassword(userAccount.getPassword(), "salt"));
        sessionFactory.getCurrentSession().save(userAccount);
    }
}



@Repository("userDao")
public class UserDaoImpl implements UserDao {

    @Autowired
    private SessionFactory sessionFactory;

    @Override
    public User getByUsername(final String username) {
        return (User) sessionFactory.getCurrentSession()
                .createQuery("from User where username = :username")
                .setParameter("username", username).uniqueResult();
    }

现在，当我创建用户，从任何其他对象获取用户时，确实工作正常，只是没有正确注入的CustomUserDetailsS​​ervice。它与其他能够使用@Autowired的服务位于同一个包com.securetest.app.service中。

我有3个context.xml文件 - 下面是我的web.xml 

<?xml version="1.0" encoding="UTF-8"?>
<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">
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/spring/root-context.xml
            /WEB-INF/spring/appServlet/security-context.xml</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>
<servlet>
    <servlet-name>appServlet</servlet-name>
    <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    <init-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>/WEB-INF/spring/appServlet/servlet-context.xml
        /WEB-INF/spring/appServlet/persistence-context.xml</param-value>
    </init-param>
    <load-on-startup>1</load-on-startup>
</servlet>
<servlet-mapping>
    <servlet-name>appServlet</servlet-name>
    <url-pattern>/</url-pattern>
</servlet-mapping>

这是我的security-context.xml 

<?xml version="1.0" encoding="UTF-8"?>
<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.xsd
                    http://www.springframework.org/schema/security 
                    http://www.springframework.org/schema/security/spring-security-3.1.xsd
                    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

    <http use-expressions="true">
        <intercept-url pattern="/exam" access="isAuthenticated()" />
        <intercept-url pattern="/" access="permitAll" />
        <intercept-url pattern="/**" access="denyAll" />
        <form-login />
        <logout invalidate-session="true" logout-success-url="/"
            logout-url="/logout" />
    </http>
    <beans:bean id="CustomUserDetailsService"
        class="com.securetest.app.service.CustomUserDetailsService" />

    <beans:bean
        class="org.springframework.security.authentication.encoding.ShaPasswordEncoder"
        id="passwordEncoder" />

    <authentication-manager>
        <authentication-provider user-service-ref='CustomUserDetailsService'>
            <password-encoder ref="passwordEncoder" />
        </authentication-provider>
    </authentication-manager>
</beans:beans>

最后只是为了确保我没有遗漏任何东西，我的servlet-context.xml - 正如你所看到的，这里我正在使用context-component-scan，它应该在com.securetest.app <中注入所有内容/ p> 

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

    <!-- DispatcherServlet Context: defines this servlet's request-processing 
        infrastructure -->

    <!-- Enables the Spring MVC @Controller programming model -->
    <annotation-driven />

    <!-- Handles HTTP GET requests for /resources/** by efficiently serving 
        up static resources in the ${webappRoot}/resources directory -->
    <resources mapping="/resources/**" location="/resources/" />

    <context:component-scan base-package="com.securetest.app." />
    <!-- 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>
    <beans:bean
        class="org.springframework.web.servlet.view.ContentNegotiatingViewResolver">
        <beans:property name="mediaTypes">
            <beans:map>
                <beans:entry key="html" value="text/html" />
                <beans:entry key="json" value="application/json" />
            </beans:map>
        </beans:property>
        <beans:property name="defaultViews">
            <beans:list>
                <beans:bean
                    class="org.springframework.web.servlet.view.json.MappingJacksonJsonView">
                    <beans:property name="prefixJson" value="true" />
                </beans:bean>
            </beans:list>
        </beans:property>
    </beans:bean>

</beans:beans>

我应该提一下，我很确定这就像我已经错误地命令我的web.xml，反之亦然，因为几乎完全相同的代码适用于另一个项目，但我看不出两者之间的区别。

为什么我没有得到autowire故障而只是nullPointerException？

编辑：在下面添加了root-context.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"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">


</beans>

2 个答案:

答案 0 :(得分：3)

您的web.xml正在创建两个Spring应用程序上下文。我们称它们为Security（在security-context.xml之后）和Servlet（在servlet-context.xml之后）。安全性由ContextLoaderListener侦听器创建，Servlet由DispatcherServlet servlet创建。安全性是Servlet的父级。这意味着Security中的bean只对Security中的其他bean可见，而Servlet中的bean可以看到Security和Servlet中的bean。

您在Security中定义了CustomUserDetailsS​​ervice（CUDS）bean，在Servlet中定义了UserAccountDao和UserDao bean，因此CUDS bean无法看到它们。如果要将它们连接到CUDS，则需要在DAO bean的安全性中添加组件扫描。

我不确定NPE。

答案 1 :(得分：1)

我认为，您的安全上下文会在您的servlet-context之前加载，@Required包含您的DAO配置。安全加载时，DAO尚未扫描，因此无需注入！使用root-context.xml进行检查。

我为我的项目执行以下操作：

<context:component-scan use-default-filters="true" base-package="com.trelta.accountmanagement, com.trelta.commons"> <context:exclude-filter type="annotation" expression="org.springframework.stereotype.Controller"/> </context:component-scan>

中的

<context:component-scan use-default-filters="false"
        base-package="com.trelta.accountmanagement, com.trelta.commons">
        <context:include-filter type="annotation"
            expression="org.springframework.stereotype.Controller" />
    </context:component-scan>

在servlet-context中：

root-context.xml

我把context-param＆amp; servlet-context.xml中的security.xml和DispatcherServlet的{​​{1}}中的init-param。该方法还增加了模块性。它会将您的WebApplicationContext相关bean保存在一个文件中，然后将其传递到您的DispatcherServlet和其他ApplicationContext bean中的单独文件中。

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