实现ApplicationContextAware-ApplicationContext为NULL [英] implementing ApplicationContextAware - ApplicationContext is NULL

问题描述

我正在编程一个Tomcat应用程序，该应用程序将充当某些内部服务的代理.

I'm programming a Tomcat application which serves as a proxy for some internal services.

我已经将Spring项目从基于XML和基于注释的混合配置切换为基于Java和基于注释的配置.

I've switched my Spring project from a mixed XML and annotation-based configuration to Java and annotation based configuration.

在切换配置样式之前，该应用程序运行良好.现在我有两个问题.

Before switching the configuration style, the app worked fine. Now I have two issues.

1. 在我的两个过滤器中执行初始化方法时，ApplicationContext为空.在调试我的应用程序时，我可以看到方法setApplicationContext已执行.

1. when executing init-methods in two of my filters, ApplicationContext is null. When I debug my App, I can see that the Method setApplicationContext is executed.

EntityManagerFactory未注入到身份验证过滤器中(emf为空)

the EntityManagerFactory is not injected in the authentication filter (emf is null)

用于引导Spring的代码:

import javax.servlet.FilterRegistration;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.ServletRegistration;
import org.springframework.web.WebApplicationInitializer;
import org.springframework.web.context.ContextLoaderListener;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;
import org.springframework.web.servlet.DispatcherServlet;

public class MyAppSpringBoot implements WebApplicationInitializer {

    @Override
    public void onStartup(ServletContext container) throws ServletException {
        initRootContext(container);
        initDispatcherContext(container);
        addFilters(container);
    }

    private void initDispatcherContext(ServletContext container) {
        AnnotationConfigWebApplicationContext servletContext = new AnnotationConfigWebApplicationContext();
        servletContext.register(MyAppDispatcherServletContext.class);
        ServletRegistration.Dynamic dispatcher
                = container.addServlet("myAppDispatcherServlet", new DispatcherServlet(servletContext));
        dispatcher.setLoadOnStartup(1);
        dispatcher.addMapping("/");
    }

    private void initRootContext(ServletContext container) {
        AnnotationConfigWebApplicationContext rootContext = new AnnotationConfigWebApplicationContext();
        rootContext.register(MyAppRootContext.class);
        container.addListener(new ContextLoaderListener(rootContext));
    }

    private void addFilters(ServletContext container) {
        FilterRegistration.Dynamic registration
                = container.addFilter("u3rAuthentication", UserDbAuthenticationFilter.class);
        registration.addMappingForUrlPatterns(null, false, "/entry/*");

        registration = container.addFilter("responseXmlFilter", ResponseTextXmlFilter.class);
        registration.addMappingForUrlPatterns(null, false, "/entry/*");
    }
}

根上下文代码:

import java.io.File;
import java.io.IOException;
import java.util.Properties;
import javax.persistence.EntityManagerFactory;
import javax.sql.DataSource;
import javax.xml.stream.XMLEventFactory;
import javax.xml.stream.XMLInputFactory;
import javax.xml.stream.XMLOutputFactory;
import org.apache.tomcat.util.http.fileupload.disk.DiskFileItemFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.jdbc.datasource.lookup.DataSourceLookupFailureException;
import org.springframework.jdbc.datasource.lookup.JndiDataSourceLookup;
import org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean;
import org.springframework.stereotype.Controller;

@Configuration
@ComponentScan(basePackages = "com.application", excludeFilters = @ComponentScan.Filter(Controller.class))
public class MyAppRootContext {

    @Bean
    public DataSource userDbJpaDataSource() throws DataSourceLookupFailureException {

        JndiDataSourceLookup lookup = new JndiDataSourceLookup();
        return lookup.getDataSource("jdbc/userDbPostgres");
    }

    @Bean
    public EntityManagerFactory entityManagerFactory() {
        //return Persistence.createEntityManagerFactory(MyAppConstants.U3R_PERSISTENCE_UNIT);
        LocalContainerEntityManagerFactoryBean fb = new LocalContainerEntityManagerFactoryBean();
        fb.setDataSource(userDbJpaDataSource());
        return fb.getNativeEntityManagerFactory();
    }

    @Bean
    public DiskFileItemFactory diskFileItemFactory() {
        DiskFileItemFactory factory = new DiskFileItemFactory();
        factory.setSizeThreshold(50_000 * 1024);
        factory.setRepository(new File("/WEB-INF/upload"));
        return factory;
    }

    @Bean
    public XMLOutputFactory xmlOutputFactory() {
        return XMLOutputFactory.newInstance();
    }

    @Bean
    public XMLInputFactory xmlInputFactory() {
        return XMLInputFactory.newInstance();
    }

    @Bean
    public XMLEventFactory xmlEventFactory() {
        return XMLEventFactory.newInstance();
    }

    @Bean
    public UrlPairing urlPairing() throws IOException {
        return new UrlPairing(myAppProperties().getProperty("myApp.UrlPairingFile"));
    }

    @Bean
    public Properties myAppProperties() throws IOException {
        Properties p = new Properties();
        p.load(MyAppRootContext.class.getResourceAsStream("/myAppConfig.properties"));
        return p;
    }

    @Bean
    public MyAppXmlFilterWords xmlFilterWords() throws IOException {
        MyAppXmlFilterWords words = MyAppXmlFilterWords.createFilterWords(myAppProperties().getProperty("myApp.xmlFilterWordFile"));
        return words;
    }

}

调度程序servlet上下文的代码:

@Configuration
@ComponentScan(
        basePackages = "de.lgn.doorman",
        includeFilters = @ComponentScan.Filter(Controller.class)
)
public class MyAppDispatcherServletContext
{
    // all beans are defined in root context
    // correct ???
}

根身份验证过滤器的代码:

@Component
public class UserDbAuthenticationFilter implements Filter, ApplicationContextAware
{
    private static final Logger logger = LogManager.getLogger(UserDbAuthenticationFilter.class.getName());

    @Autowired
    EntityManagerFactory emf;

    private ApplicationContext appContext;

    @Override
    public void init(FilterConfig filterConfig)    
    {
        logger.debug("Filter {} initialisiert. App-Context: {} {}", this.getClass().getName(),appContext.hashCode(), appContext);
        // *******************  NullPointerException here *******************
    }

    @Override
    public void destroy()
    { }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException
    {
        appContext = applicationContext;
    }

    /*
    @PostConstruct    // ***************** this annotation isn't working **********************
    public void filterInit() throws ServletException
    {
        logger.debug("Filter {} initialisiert. App-Context: {} {}", this.getClass().getName(),appContext.hashCode(), appContext);
    }

    */
}

在我的控制器中，ApplicationContext是正确的(不是null).

In my controller, the ApplicationContext is correct (not null).

@Controller
@RequestMapping(value = "entry/**")
public class MyAppProxyController implements ApplicationContextAware
{

    @Autowired
    Properties myAppProperties;

    private ApplicationContext appContext;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException
    {
        appContext = applicationContext;
    }

    @PostConstruct
    public void init() throws ServletException   // this is working fine
    {
        logger.debug("Controller {} initialisiert. App-Context: {} {}", this.getClass().getName(),
                appContext.hashCode(), appContext);

        logger.debug("Beans im Zugriff von Controller:");
        for (String beanName : appContext.getBeanDefinitionNames())
        {
            logger.debug("          {}", beanName);
        }
        MyAppProxyController controller = (MyAppProxyController) appContext.getBean("myAppProxyController");
        logger.debug("controller-hash im Controller={}", controller.hashCode());
    }
}    

更新为塞尔吉·贝莱斯塔(Serge Ballesta)的答案

我遵循了您的所有第二条说明.但是现在我得到了这个异常:

Update to the answer of Serge Ballesta

I followed all your instructions #2. But now I get this exception:

13-Aug-2015 13:03:27.264 INFO [RMI TCP Connection(3)-127.0.0.1] org.apache.catalina.core.ApplicationContext.log Spring WebApplicationInitializers detected on classpath: [de.lgn.doorman.config.DmSpringBoot@c427b4f]
13-Aug-2015 13:03:27.655 INFO [RMI TCP Connection(3)-127.0.0.1] org.apache.catalina.core.ApplicationContext.log Initializing Spring root WebApplicationContext
13-Aug-2015 13:03:28.308 SEVERE [RMI TCP Connection(3)-127.0.0.1] org.apache.catalina.core.StandardContext.filterStart Exception starting filter responseXmlFilter
 org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'responseXmlFilter' is defined
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanDefinition(DefaultListableBeanFactory.java:698)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getMergedLocalBeanDefinition(AbstractBeanFactory.java:1174)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:283)

我想知道当我使用3次DelegatingFilterProxy时如何将自己的过滤器连接到链上.方法addFilter中的参数name是否与bean名称相关?

I wonder how my own filters are connected to the chain when I use three times DelegatingFilterProxy. Is the paramter name in the method addFilter associated with the bean name?

这是用于在引导代码中创建过滤器链的代码:

This is the code for creating the filter chain in the bootstrap code:

private void addFilters(ServletContext container)
{
    FilterRegistration.Dynamic registration =
            container.addFilter("userDbAuthenticationFilter", DelegatingFilterProxy.class);
    registration.addMappingForUrlPatterns(null, false, "/mapgate/*");

    registration = container.addFilter("prepareRequestFilter", DelegatingFilterProxy.class);
    registration.addMappingForUrlPatterns(null, false, "/mapgate/*");

    registration = container.addFilter("responseTextXmlFilter", DelegatingFilterProxy.class);
    registration.addMappingForUrlPatterns(null, false, "/mapgate/*");
}

这些是我在 root上下文中的filter bean定义:

These are my filter bean definitions in the root context:

@Configuration
@ComponentScan(basePackages = "com.application", excludeFilters = @ComponentScan.Filter(Controller.class))
public class MyAppRootContext
{

    @Bean
    public UserDbAuthenticationFilter userDbAuthenticationFilter()
    {
        return new UserDbAuthenticationFilter();
    }

    @Bean
    public PrepareRequestFilter prepareRequestFilter()
    {
        return new PrepareRequestFilter();
    }

    @Bean
    public ResponseTextXmlFilter responseTextXmlFilter()
    {
        return new ResponseTextXmlFilter();
    }

    @Bean
    public DataSource userDbJpaDataSource() throws DataSourceLookupFailureException
    {

        JndiDataSourceLookup lookup = new JndiDataSourceLookup();
        return lookup.getDataSource("jdbc/userDbPostgres");
    }

    @Bean
    public EntityManagerFactory entityManagerFactory()
    {
        LocalContainerEntityManagerFactoryBean fb = new LocalContainerEntityManagerFactoryBean();
        fb.setDataSource(userDbJpaDataSource());
        return fb.getNativeEntityManagerFactory();
    }
}

过滤器仍然没有依赖项注入.是因为过滤器链是在引导阶段创建的，而Bean是在根上下文中创建的?

There is still no dependency injection to the filters. Is it because the filter chain is created during the bootstrap phase, and the beans are created in the root context?

这是身份验证过滤器中的基本代码:

This is the essential code in the authentication filter :

public class U3RAuthenticationFilter implements Filter, ApplicationContextAware
{
    private static final Logger logger = LogManager.getLogger(U3RAuthenticationFilter.class.getName());

    @Autowired(required = true)
    EntityManagerFactory entityManagerFactory;

    private ApplicationContext appContext;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException
    {
        appContext = applicationContext;
    }

    @PostConstruct
    public void filterInit() throws ServletException
    {
        logger.debug("Filter {} initialisiert. App-Context: {} {}", this.getClass().getName(),appContext.hashCode(), appContext);
        logger.debug("Beans accessable by {}:", this.getClass().getName());
        for (String beanName : appContext.getBeanDefinitionNames())
        {
            logger.debug("          {}", beanName);
        }

        logger.debug("EntityManagerFactory: {}", (EntityManagerFactory)appContext.getBean("entityManagerFactory"));
    }
}

没有引发异常.这是日志记录:

No exception is thrown. This the logging:

20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1] controller-hash im Controller=1481031354
20150814-090718 INFO  [RMI TCP Connection(3)-127.0.0.1] Mapped "{[/mapgate/**],methods=[GET]}" onto protected void com.application.controller.MyAppProxyController.doGet(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse)
20150814-090718 INFO  [RMI TCP Connection(3)-127.0.0.1] Mapped "{[/mapgate/**],methods=[POST]}" onto protected void com.application.controller.MyAppProxyController.doPost(javax.servlet.http.HttpServletRequest,javax.servlet.http.HttpServletResponse) throws javax.servlet.ServletException,java.io.IOException
20150814-090718 INFO  [RMI TCP Connection(3)-127.0.0.1] Looking for @ControllerAdvice: WebApplicationContext for namespace 'myAppDispatcherServlet-servlet': startup date [Fri Aug 14 09:07:18 CEST 2015]; parent: Root WebApplicationContext
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1] Filter com.application.filter.UserDbAuthenticationFilter initialisiert. App-Context: 641348200 WebApplicationContext for namespace 'myAppDispatcherServlet-servlet': startup date [Fri Aug 14 09:07:18 CEST 2015]; parent: Root WebApplicationContext
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1] Beans accessable by com.application.filter.UserDbAuthenticationFilter:
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           org.springframework.context.annotation.internalConfigurationAnnotationProcessor
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           org.springframework.context.annotation.internalAutowiredAnnotationProcessor
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           org.springframework.context.annotation.internalRequiredAnnotationProcessor
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           org.springframework.context.annotation.internalCommonAnnotationProcessor
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           org.springframework.context.annotation.internalPersistenceAnnotationProcessor
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           org.springframework.context.event.internalEventListenerProcessor
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           org.springframework.context.event.internalEventListenerFactory
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           myAppDispatcherServletContext
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           org.springframework.context.annotation.ConfigurationClassPostProcessor.importAwareProcessor
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           org.springframework.context.annotation.ConfigurationClassPostProcessor.enhancedConfigurationProcessor
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           myAppRootContext
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           myAppProxyController
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           org.springframework.web.servlet.config.annotation.DelegatingWebMvcConfiguration
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           requestMappingHandlerMapping
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           mvcContentNegotiationManager
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           viewControllerHandlerMapping
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           beanNameHandlerMapping
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           resourceHandlerMapping
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           mvcResourceUrlProvider
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           defaultServletHandlerMapping
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           requestMappingHandlerAdapter
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           mvcConversionService
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           mvcValidator
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           mvcPathMatcher
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           mvcUrlPathHelper
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           mvcUriComponentsContributor
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           httpRequestHandlerAdapter
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           simpleControllerHandlerAdapter
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           handlerExceptionResolver
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           mvcViewResolver
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           userDbAuthenticationFilter
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           prepareRequestFilter
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           responseTextXmlFilter
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           myAppFilterChain
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           userDbJpaDataSource
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           <b>entityManagerFactory</b>
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           diskFileItemFactory
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           xmlOutputFactory
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           xmlInputFactory
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           xmlEventFactory
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           urlPairing
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           myAppProperties
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1]           xmlFilterWords
20150814-090718 DEBUG [RMI TCP Connection(3)-127.0.0.1] <b>EntityManagerFactory: null</b>

推荐答案

由于应用程序上下文已正确注入控制器中，因此我假设Spring已正确初始化.但是您的过滤器被声明为原始过滤器，而不是spring bean，因此它们上的spring注释将被忽略.

As the application context is correctly injected in your controller, I assume that Spring is correctly initialized. But your filters are declared as raw filters, not as spring beans, so the spring annotations are ignored on them.

您可以通过两种方式访问​​应用程序上下文:

You have two ways to get access to the application context:

1. 原始过滤器(未启用Spring)可以使用WebApplicationContext WebApplicationContextUtils.getWebApplicationContext(ServletContext sc)访问根应用程序上下文.例如，您可以更改init方法:

1. a raw filter (not Spring enabled) can get access to the root application context with WebApplicationContext WebApplicationContextUtils.getWebApplicationContext(ServletContext sc). For example, you could change your init method:

@Override
public void init(FilterConfig filterConfig)    
{
    ServletContex sc = filterConfig.getServletContext();
    appContext = WebApplicationContextUtils.getWebApplicationContext(sc);
    logger.debug("Filter {} initialisiert. App-Context: {} {}", this.getClass().getName(),appContext.hashCode(), appContext);
}

您还可以使用DelegatingFilterProxy有效地将bean用作过滤器:

you can also use a DelegatingFilterProxy to effectively use beans as filters:

将添加过滤器更改为:

private void addFilters(ServletContext container) {
    FilterRegistration.Dynamic registration
            = container.addFilter("u3rAuthentication", DelegatingFilterProxy.class);
    registration.addMappingForUrlPatterns(null, false, "/entry/*");

    registration = container.addFilter("responseXmlFilter", DelegatingFilterProxy.class);
    registration.addMappingForUrlPatterns(null, false, "/entry/*");
}

在您的根上下文中添加过滤器bean:

add filter beans in your root context:

@Bean
public UserDbAuthenticationFilter u3rAuthentication() { 
    return new UserDbAuthenticationFilter();
}

@Bean
public ResponseTextXmlFilter responseXmlFilter() { 
    return new ResponseTextXmlFilter();
}

将不再调用init方法，但这将起作用:

the init method will no longer be called, but this would work:

@PostConstruct
public void filterInit() throws ServletException
{
    logger.debug("Filter {} initialisiert. App-Context: {} {}", this.getClass().getName(),appContext.hashCode(), appContext);
}

这篇关于实现ApplicationContextAware-ApplicationContext为NULL的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！