Question

我有两节课。

CustomUserDetailsService - 工作正常！


@Service
@Transactional(readOnly = true)
@SuppressWarnings("unused")
public class CustomUserDetailsService implements UserDetailsService {

    @Autowired
    private UserDAO userDAO;

    @Override
    public UserDetails loadUserByUsername(String login) throws UsernameNotFoundException {
        return userDAO.getUser(login);
    }

    public UserDAO getUserDAO() {
        return userDAO;
    }

    public void setUserDAO(UserDAO userDAO) {
        this.userDAO = userDAO;
    }
}

RegistrationServiceImpl - 在userDAO.addUser(newUser);方法调用上抛出NullPointerException。


@Service
@Transactional(readOnly = false)
public class RegistrationServiceImpl implements RegistrationService {

    @Autowired
    private UserDAO userDAO;


    @Override
    public void registerUser(Registration reg) {

        User newUser = new User();

        newUser.setUsername(reg.getUsername());
        newUser.setPassword(reg.getPassword());
        newUser.setFirstName(reg.getFirstName());
        newUser.setLastName(reg.getLastName());

        userDAO.addUser(newUser);
    }

    public UserDAO getUserDAO() {
        return userDAO;
    }

    public void setUserDAO(UserDAO userDAO) {
        this.userDAO = userDAO;
    }
}

MVC-调度-servlet.xml中

<?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:tx="http://www.springframework.org/schema/tx"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
              http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
              http://www.springframework.org/schema/aop
              http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
              http://www.springframework.org/schema/context
              http://www.springframework.org/schema/context/spring-context-2.5.xsd
              http://www.springframework.org/schema/tx
              http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">
    <context:annotation-config/>

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

    <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/pages/"/>
        <property name="suffix" value=".jsp" />
    </bean>

    <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="com.mysql.jdbc.Driver" />
        <property name="url" value="jdbc:mysql://localhost:3306/Library" />
        <property name="username" value="root" />
        <property name="password" value="G190419g" />
    </bean>

    <bean id="sessionFactory" class="org.springframework.orm.hibernate4.LocalSessionFactoryBean">
        <property name="packagesToScan" value="com.petrez" />
        <property name="dataSource" ref="dataSource" />
        <property name="hibernateProperties">
            <props>
                <prop key="hibernate.dialect">org.hibernate.dialect.MySQLDialect</prop>
                <prop key="show_sql">false</prop>
            </props>
        </property>
        <property name="annotatedClasses">
            <list>
                <value>com.petrez.model.User</value>
                <value>com.petrez.model.Role</value>
            </list>
        </property>
    </bean>

    <bean id="transactionManager" class="org.springframework.orm.hibernate4.HibernateTransactionManager">
        <property name="sessionFactory" ref="sessionFactory"/>
    </bean>

    <bean id="userDAO" class="com.petrez.dao.UserDAOImpl" />

    <bean id="roleDAO" class="com.petrez.dao.RoleDAOImpl" />

    <bean id="userDetailsService" class="com.petrez.service.CustomUserDetailsService" />

    <bean id="registrationService" class="com.petrez.service.RegistrationServiceImpl" />

    <tx:annotation-driven transaction-manager="transactionManager" />
</beans>

任何人都可以说我，为什么？谢谢！

UPD 堆栈跟踪：

Nov 08, 2013 11:04:33 PM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [mvc-dispatcher] in context with path [] threw exception [Request processing failed; nested exception is java.lang.NullPointerException] with root cause
java.lang.NullPointerException
    at com.petrez.service.RegistrationServiceImpl.registerUser(RegistrationServiceImpl.java:28)
    at com.petrez.controller.RegistrationPage.processRegistration(RegistrationPage.java:23)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:601)
    at org.springframework.web.bind.annotation.support.HandlerMethodInvoker.invokeHandlerMethod(HandlerMethodInvoker.java:176)
    at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.invokeHandlerMethod(AnnotationMethodHandlerAdapter.java:440)
    at org.springframework.web.servlet.mvc.annotation.AnnotationMethodHandlerAdapter.handle(AnnotationMethodHandlerAdapter.java:428)
    at org.springframework.web.servlet.DispatcherServlet.doDispatch(DispatcherServlet.java:925)
    at org.springframework.web.servlet.DispatcherServlet.doService(DispatcherServlet.java:856)
    at org.springframework.web.servlet.FrameworkServlet.processRequest(FrameworkServlet.java:936)
    at org.springframework.web.servlet.FrameworkServlet.doPost(FrameworkServlet.java:838)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
    at org.springframework.web.servlet.FrameworkServlet.service(FrameworkServlet.java:812)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.invoke(FilterSecurityInterceptor.java:118)
    at org.springframework.security.web.access.intercept.FilterSecurityInterceptor.doFilter(FilterSecurityInterceptor.java:84)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    at org.springframework.security.web.access.ExceptionTranslationFilter.doFilter(ExceptionTranslationFilter.java:113)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    at org.springframework.security.web.session.SessionManagementFilter.doFilter(SessionManagementFilter.java:103)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    at org.springframework.security.web.authentication.AnonymousAuthenticationFilter.doFilter(AnonymousAuthenticationFilter.java:113)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    at org.springframework.security.web.servletapi.SecurityContextHolderAwareRequestFilter.doFilter(SecurityContextHolderAwareRequestFilter.java:54)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    at org.springframework.security.web.savedrequest.RequestCacheAwareFilter.doFilter(RequestCacheAwareFilter.java:45)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    at org.springframework.security.web.authentication.www.BasicAuthenticationFilter.doFilter(BasicAuthenticationFilter.java:150)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    at org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:183)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    at org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:105)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    at org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:87)
    at org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:342)
    at org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:192)
    at org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:160)
    at org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:343)
    at org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:260)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1023)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:722)

RegistrationPage


@Controller
@RequestMapping(value = "/registration")
@SuppressWarnings("unused")
public class RegistrationPage {

    @RequestMapping(method = RequestMethod.POST)
    public String processRegistration(@ModelAttribute("reg") Registration reg, BindingResult result) {
        if(result.hasErrors()) {
            return "/?error=true";
        }
        else {
            new RegistrationServiceImpl().registerUser(reg);
            return "success-login";
        }
    }
}

Answer 1

您手动实例化RegistrationServiceImpl，而不是从上下文中检索Spring管理的bean。将RegistrationService注入RegistrationPage。

Answer 2

您在配置中错过了<context:annotation-config/>

添加<context:annotation-config/>或<context:component-scan base-package="org.example"/>

到mvc-dispatcher-servlet.xml配置文件的顶部。

例如

<?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:tx="http://www.springframework.org/schema/tx"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans
              http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
              http://www.springframework.org/schema/aop
              http://www.springframework.org/schema/aop/spring-aop-2.5.xsd
              http://www.springframework.org/schema/context
              http://www.springframework.org/schema/context/spring-context-2.5.xsd
              http://www.springframework.org/schema/tx
              http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">    

            <context:component-scan base-package="org.example"/> 

    <bean id="viewResolver" class="org.springframework.web.servlet.view.InternalResourceViewResolver">
        <property name="prefix" value="/WEB-INF/pages/"/>
        <property name="suffix" value=".jsp" />        
    </bean>


</beans>

弹簧。自动对象NullPointerException

2 个答案: