Spring Autowired Null Pointer Exception-Java 学习之路

-2

我在使用Spring-MVC（4.2.5），Spring-Security（4.0.3）和MongoDB开发一个非常简单的Web应用程序时遇到了一些问题 .

我正在尝试实现自定义身份验证提供程序，以便使用DAO模式通过数据库登录用户 . 虽然它似乎已经正确初始化了应用程序上下文，但我在Autowired变量（CustomerDao和CustomUserDetailsService）上有Null Pointer Exception .

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns="http://xmlns.jcp.org/xml/ns/javaee"
    xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd"
    id="WebApp_ID" version="3.1">
    <display-name>AcmeSpring</display-name>
    <servlet>
        <servlet-name>SpringController</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>/WEB-INF/spring-mvc.xml</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>
    <servlet-mapping>
        <servlet-name>SpringController</servlet-name>
        <url-pattern>/</url-pattern>
    </servlet-mapping>
    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>
            /WEB-INF/spring-security.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>
</web-app>

spring-mvc.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:mvc="http://www.springframework.org/schema/mvc"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://www.springframework.org/schema/beans"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:mongo="http://www.springframework.org/schema/data/mongo"
    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
        http://www.springframework.org/schema/data/mongo 
        http://www.springframework.org/schema/data/mongo/spring-mongo-1.5.xsd">

    <mvc:annotation-driven />
    <context:component-scan base-package="controller" />
    <context:component-scan base-package="model" />
    <context:component-scan base-package="dao" />
    <context:component-scan base-package="service" />

    <mvc:resources mapping="/resources/**" location="/resources/" />

    <bean id="templateResolver"
        class="org.thymeleaf.templateresolver.ServletContextTemplateResolver">
        <property name="prefix" value="/WEB-INF/html/" />
        <property name="suffix" value=".html" />
        <property name="templateMode" value="HTML5" />
    </bean>

    <bean id="templateEngine" class="org.thymeleaf.spring4.SpringTemplateEngine">
        <property name="templateResolver" ref="templateResolver" />
    </bean>

    <bean class="org.thymeleaf.spring4.view.ThymeleafViewResolver">
        <property name="templateEngine" ref="templateEngine" />
        <property name="order" value="1" />
    </bean>

    <mongo:db-factory id="mongoDbFactory" host="localhost"
        port="27017" dbname="AcmeSpring" />

    <bean id="mongoTemplate" class="org.springframework.data.mongodb.core.MongoTemplate">
        <constructor-arg ref="mongoDbFactory" />
    </bean>

    <bean id="customerDao" class="dao.CustomerDaoImpl">
    </bean>
</beans>

spring-security.xml

<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-4.0.xsd
    http://www.springframework.org/schema/security
    http://www.springframework.org/schema/security/spring-security-4.0.xsd">

    <http pattern="/resources/**" security="none" />

    <http auto-config="true">
        <intercept-url pattern="/user/**" access="hasRole('USER')" />
        <form-login authentication-failure-url="/login" login-page="/login"
            login-processing-url="/login" default-target-url="/user" />
        <logout invalidate-session="true" success-handler-ref="logoutSuccessHandler" />
    </http>

    <authentication-manager>
        <authentication-provider ref="customAuthenticationProvider" />
    </authentication-manager>

    <beans:bean id="customUserDetailsService" class="service.CustomUserDetailsService">
    </beans:bean>

    <beans:bean id="customAuthenticationProvider" class="service.CustomAuthenticationProvider">
    </beans:bean>

    <beans:bean id="logoutSuccessHandler" class="service.CustomLogoutSuccessHandler">
    </beans:bean>
</beans:beans>

CustomAuthenticationProvider

@Component
public class CustomAuthenticationProvider implements AuthenticationProvider {
    @Autowired
    CustomUserDetailsService userDetails;

    @Override
    public Authentication authenticate(Authentication authentication) throws AuthenticationException {
        String username = authentication.getName();
        String password = authentication.getCredentials().toString();

        System.out.println(userDetails == null);

        Customer customer = userDetails.loadUserByUsername(username);

        if(customer == null) {
            throw new BadCredentialsException("Username errato");
        }

        if(!password.equals(customer.getPassword())) {
            throw new BadCredentialsException("Password errata");
        }

        List<GrantedAuthority> authorities = new ArrayList<>();
        authorities.add(new SimpleGrantedAuthority(customer.getRole()));

        return new UsernamePasswordAuthenticationToken(customer, password, authorities);
    }

    @Override
    public boolean supports(Class<?> clazz) {
        return clazz.equals(UsernamePasswordAuthenticationToken.class);
    }
}

CustomUserDetailsService

@Service
public class CustomUserDetailsService implements UserDetailsService {
    @Autowired
    private CustomerDao customerDao;

    @Override
    public Customer loadUserByUsername(String username) throws UsernameNotFoundException {
        return customerDao.findCustomerByUsername(username);
    }
}

CustomerDaoImpl

@Repository
public class CustomerDaoImpl implements CustomerDao {
    private static final String COLLECTION = "Customer";
    @Autowired
    private MongoTemplate mongoTemplate;

    @Override
    public void create(Customer customer) {
        this.mongoTemplate.insert(customer, COLLECTION);
    }

    @Override
    public Customer findCustomerByUsername(String username) {
        Query query = new Query();
        query.addCriteria(Criteria.where("username").is(username));
        System.out.println(query.toString());
        return this.mongoTemplate.findOne(query, Customer.class);
    }
}

stack trace

java.lang.NullPointerException
    service.CustomUserDetailsService.loadUserByUsername(CustomUserDetailsService.java:18)
    service.CustomAuthenticationProvider.authenticate(CustomAuthenticationProvider.java:32)
    org.springframework.security.authentication.ProviderManager.authenticate(ProviderManager.java:167)
    org.springframework.security.authentication.ProviderManager.authenticate(ProviderManager.java:192)
    org.springframework.security.web.authentication.UsernamePasswordAuthenticationFilter.attemptAuthentication(UsernamePasswordAuthenticationFilter.java:93)
    org.springframework.security.web.authentication.AbstractAuthenticationProcessingFilter.doFilter(AbstractAuthenticationProcessingFilter.java:217)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    org.springframework.security.web.authentication.logout.LogoutFilter.doFilter(LogoutFilter.java:120)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    org.springframework.security.web.csrf.CsrfFilter.doFilterInternal(CsrfFilter.java:120)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    org.springframework.security.web.header.HeaderWriterFilter.doFilterInternal(HeaderWriterFilter.java:64)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    org.springframework.security.web.context.request.async.WebAsyncManagerIntegrationFilter.doFilterInternal(WebAsyncManagerIntegrationFilter.java:53)
    org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:107)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    org.springframework.security.web.context.SecurityContextPersistenceFilter.doFilter(SecurityContextPersistenceFilter.java:91)
    org.springframework.security.web.FilterChainProxy$VirtualFilterChain.doFilter(FilterChainProxy.java:330)
    org.springframework.security.web.FilterChainProxy.doFilterInternal(FilterChainProxy.java:213)
    org.springframework.security.web.FilterChainProxy.doFilter(FilterChainProxy.java:176)
    org.springframework.web.filter.DelegatingFilterProxy.invokeDelegate(DelegatingFilterProxy.java:346)
    org.springframework.web.filter.DelegatingFilterProxy.doFilter(DelegatingFilterProxy.java:262)

我哪里错了？先感谢您 .

编辑：我没有手动初始化自动装配变量，只是粘贴不好，我编辑了我的代码 .

EDIT2：正如@iMysak所建议的，我从spring-mvc.xml中删除了customerDao bean声明，并从spring-security.xml中删除了3个service bean声明

new stack trace

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.security.filterChains': Cannot resolve reference to bean 'org.springframework.security.web.DefaultSecurityFilterChain#1' while setting bean property 'sourceList' with key [1]; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.security.web.DefaultSecurityFilterChain#1': Cannot create inner bean '(inner bean)#5adbfd3' of type [org.springframework.security.web.authentication.logout.LogoutFilter] while setting constructor argument with key [4]; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#5adbfd3': Cannot resolve reference to bean 'logoutSuccessHandler' while setting constructor argument; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'logoutSuccessHandler' is defined
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:359)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:108)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveManagedList(BeanDefinitionValueResolver.java:382)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:157)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1481)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1226)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:543)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:753)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:839)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:538)
    at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:444)
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:326)
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:107)
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4853)
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5314)
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:145)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1408)
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1398)
    at java.util.concurrent.FutureTask.run(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
    at java.lang.Thread.run(Unknown Source)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.security.web.DefaultSecurityFilterChain#1': Cannot create inner bean '(inner bean)#5adbfd3' of type [org.springframework.security.web.authentication.logout.LogoutFilter] while setting constructor argument with key [4]; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#5adbfd3': Cannot resolve reference to bean 'logoutSuccessHandler' while setting constructor argument; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'logoutSuccessHandler' is defined
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveInnerBean(BeanDefinitionValueResolver.java:313)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:129)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveManagedList(BeanDefinitionValueResolver.java:382)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:157)
    at org.springframework.beans.factory.support.ConstructorResolver.resolveConstructorArguments(ConstructorResolver.java:634)
    at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:140)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1143)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1046)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:510)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:351)
    ... 26 more
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)#5adbfd3': Cannot resolve reference to bean 'logoutSuccessHandler' while setting constructor argument; nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'logoutSuccessHandler' is defined
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:359)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:108)
    at org.springframework.beans.factory.support.ConstructorResolver.resolveConstructorArguments(ConstructorResolver.java:634)
    at org.springframework.beans.factory.support.ConstructorResolver.autowireConstructor(ConstructorResolver.java:140)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireConstructor(AbstractAutowireCapableBeanFactory.java:1143)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1046)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:510)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveInnerBean(BeanDefinitionValueResolver.java:299)
    ... 40 more
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'logoutSuccessHandler' is defined
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanDefinition(DefaultListableBeanFactory.java:698)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getMergedLocalBeanDefinition(AbstractBeanFactory.java:1175)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:284)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197)
    at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:351)
    ... 48 more

我也尝试按照建议here添加aop，tx和表达式依赖项，但我得到了上面的堆栈跟踪

3 回答

0
使用多个 context:component-scan 标签可能会出现问题 . 请尝试下一步：
```
<context:component-scan base-package="controller model dao service" />
```
而不是单独声明它们 .
回复于 2024-05-05T02:12:37+08:00
1
你犯了经典的Spring bean错误 . 你注释了bean：
```
@Autowired
CustomUserDetailsService userDetails;
```
你叫新：
```
userDetails = new CustomUserDetailsService();
```
它可以在Spring控制之下，也可以在你的控制之下 . 你打电话给新人的那一刻，它已经脱离了 Spring 天的手 .

如果您希望Spring自动连接依赖项，则无法调用new来初始化引用 . 让 Spring 天去做吧 .
回复于 2024-05-05T02:12:37+08:00

你能尝试摆脱吗？

<beans:bean id="customAuthenticationProvider" class="service.CustomAuthenticationProvider">
</beans:bean>

和

<beans:bean id="customUserDetailsService" class="service.CustomUserDetailsService">
    </beans:bean>

我认为XML声明可能是注释声明和组件扫描的冗余

回复于 2024-05-05T02:12:37+08:00

Spring Autowired Null Pointer Exception

3 回答

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