java - Spring Bootstrap 和 Aspect 是如何实现的？

Question

我尝试配置日志记录方面，但我不明白它是如何工作的。

我有一个 spring web mvc 应用程序。考虑一下:

带有 LoggingConfiguration 的配置类包:

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.EnableAspectJAutoProxy;

import my.package.aspects.LoggingAspect;
import my.package.web.controller.MemberController;

@Configuration
@EnableAspectJAutoProxy
public class LoggingConfiguration {
    @Bean
    public LoggingAspect loggingAspect() {
        return new LoggingAspect();
    }

    @Bean 
    MemberController memberController(){
        return new MemberController();
    }
}

一个方面:

@Aspect
@Component
public class LoggingAspect {
    static Logger log = LoggerFactory.getLogger(LoggingAspect.class);

    @Before("execution(* my.package..*.*(..) )")
    public void logBefore(JoinPoint joinPoint) {
        log.debug("logBefore() is running!");
        log.debug(joinPoint.getSignature().getName());

    }
}

一个 log4j.xml(定义了 appender)

<logger name="my.package" additivity="false">
    <appender-ref ref="consoleAppender" />
    <appender-ref ref="fileControllerAppender" />
</logger>

为什么配置不起作用？

谢谢

编辑

web.xml 是

    <?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee"
    xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
                        http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">

    <display-name>Archetype Created Web Application</display-name>

    <context-param>
        <param-name>contextClass</param-name>
        <param-value>org.springframework.web.context.support.AnnotationConfigWebApplicationContext</param-value>
    </context-param>
    <context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>my.package.config.JpaConfiguration</param-value>
    </context-param>

    <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener>

    <servlet>
        <servlet-name>spring</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
        <init-param>
            <param-name>contextClass</param-name>
            <param-value>org.springframework.web.context.support.AnnotationConfigWebApplicationContext</param-value>
        </init-param>
        <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>my.package.config.WebConfiguration</param-value>
        </init-param>
        <load-on-startup>1</load-on-startup>
    </servlet>

    <servlet-mapping>
        <servlet-name>spring</servlet-name>
        <url-pattern>/</url-pattern>
        <url-pattern>*.html</url-pattern>   
    </servlet-mapping>
    <!--  
    <listener>
        <listener-class>org.springframework.web.util.Log4jConfigListener</listener-class>
    </listener>
    <context-param>
        <param-name>log4jConfigLocation</param-name>
        <param-value>classpath:log4j.xml</param-value>
    </context-param>
    -->
    <session-config>
        <session-timeout>30</session-timeout>
    </session-config>

    <welcome-file-list>
        <welcome-file>index.html</welcome-file>
    </welcome-file-list>

</web-app>

编辑我想在 web.xml 中添加 LoggingConfiguration。现在，我有这个:

<init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value>my.package.config.WebConfiguration, my.package.config.LoggingConfiguration</param-value>
        </init-param>

但是我有这个消息:

Error creating bean with name 'viewResolver' defined in class my.package.config.WebConfiguration: No matching factory method found: factory bean 'webConfiguration'; factory method 'getViewResolver()'. Check that a method with the specified name exists and that it is non-static.

我尝试通过删除 web.xml 中的行并在 WebConfiguration 中添加 @Import(LoggingConfiguration.class) 但我收到了相同的消息。

WebConfiguration 是:

@Configuration
@EnableWebMvc
@ComponentScan("my.package.web.controller")
public class WebConfiguration {

    @Bean(name = "viewResolver")
    public InternalResourceViewResolver getViewResolver() {
        InternalResourceViewResolver viewResolver = new InternalResourceViewResolver();
        viewResolver.setPrefix("/WEB-INF/pages/");
        viewResolver.setSuffix(".jsp");
        return viewResolver;
    }

}

编辑

完整的 stackTrace 是:

org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'viewResolver' defined in class my.package.config.WebConfiguration: Instantiation of bean failed; nested exception is org.springframework.beans.factory.BeanDefinitionStoreException: Factory method [public org.springframework.web.servlet.view.InternalResourceViewResolver my.package.config.WebConfiguration.viewResolver()] threw exception; nested exception is org.springframework.cglib.core.CodeGenerationException: java.lang.reflect.InvocationTargetException-->null
    at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:589)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1055)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:951)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:487)
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:458)
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:296)
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:223)
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:293)
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:194)
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:628)
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:932)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:479)
    at org.springframework.web.servlet.FrameworkServlet.configureAndRefreshWebApplicationContext(FrameworkServlet.java:651)
    at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:599)
    at org.springframework.web.servlet.FrameworkServlet.createWebApplicationContext(FrameworkServlet.java:665)
    at org.springframework.web.servlet.FrameworkServlet.initWebApplicationContext(FrameworkServlet.java:518)
    at org.springframework.web.servlet.FrameworkServlet.initServletBean(FrameworkServlet.java:459)
    at org.springframework.web.servlet.HttpServletBean.init(HttpServletBean.java:136)
    at javax.servlet.GenericServlet.init(GenericServlet.java:241)
    at org.mortbay.jetty.servlet.ServletHolder.initServlet(ServletHolder.java:440)
    at org.mortbay.jetty.servlet.ServletHolder.doStart(ServletHolder.java:263)
    at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
    at org.mortbay.jetty.servlet.ServletHandler.initialize(ServletHandler.java:736)
    at org.mortbay.jetty.servlet.Context.startContext(Context.java:140)
    at org.mortbay.jetty.webapp.WebAppContext.startContext(WebAppContext.java:1282)
    at org.mortbay.jetty.handler.ContextHandler.doStart(ContextHandler.java:518)
    at org.mortbay.jetty.webapp.WebAppContext.doStart(WebAppContext.java:499)
    at org.mortbay.jetty.plugin.Jetty6PluginWebAppContext.doStart(Jetty6PluginWebAppContext.java:115)
    at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
    at org.mortbay.jetty.handler.HandlerCollection.doStart(HandlerCollection.java:152)
    at org.mortbay.jetty.handler.ContextHandlerCollection.doStart(ContextHandlerCollection.java:156)
    at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
    at org.mortbay.jetty.handler.HandlerCollection.doStart(HandlerCollection.java:152)
    at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
    at org.mortbay.jetty.handler.HandlerWrapper.doStart(HandlerWrapper.java:130)
    at org.mortbay.jetty.Server.doStart(Server.java:224)
    at org.mortbay.component.AbstractLifeCycle.start(AbstractLifeCycle.java:50)
    at org.mortbay.jetty.plugin.Jetty6PluginServer.start(Jetty6PluginServer.java:132)
    at org.mortbay.jetty.plugin.AbstractJettyMojo.startJetty(AbstractJettyMojo.java:454)
    at org.mortbay.jetty.plugin.AbstractJettyMojo.execute(AbstractJettyMojo.java:396)
    at org.mortbay.jetty.plugin.AbstractJettyRunMojo.execute(AbstractJettyRunMojo.java:210)
    at org.mortbay.jetty.plugin.Jetty6RunMojo.execute(Jetty6RunMojo.java:184)
    at org.apache.maven.plugin.DefaultBuildPluginManager.executeMojo(DefaultBuildPluginManager.java:101)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:209)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:153)
    at org.apache.maven.lifecycle.internal.MojoExecutor.execute(MojoExecutor.java:145)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:84)
    at org.apache.maven.lifecycle.internal.LifecycleModuleBuilder.buildProject(LifecycleModuleBuilder.java:59)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.singleThreadedBuild(LifecycleStarter.java:183)
    at org.apache.maven.lifecycle.internal.LifecycleStarter.execute(LifecycleStarter.java:161)
    at org.apache.maven.DefaultMaven.doExecute(DefaultMaven.java:320)
    at org.apache.maven.DefaultMaven.execute(DefaultMaven.java:156)
    at org.apache.maven.cli.MavenCli.execute(MavenCli.java:537)
    at org.apache.maven.cli.MavenCli.doMain(MavenCli.java:196)
    at org.apache.maven.cli.MavenCli.main(MavenCli.java:141)
    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:606)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launchEnhanced(Launcher.java:290)
    at org.codehaus.plexus.classworlds.launcher.Launcher.launch(Launcher.java:230)
    at org.codehaus.plexus.classworlds.launcher.Launcher.mainWithExitCode(Launcher.java:409)
    at org.codehaus.plexus.classworlds.launcher.Launcher.main(Launcher.java:352)

Answer 1

问题是由于您的 Aspect 和 @Configuration 类的使用而引入的。

切面中的切入点将应用于应用程序上下文中的所有 bean。 @Configuration 类也是 @Components 它们是上下文中的 beans(特殊的 beans，但仍然是 beans)。 @Configuration bean 被视为某种特殊的工厂 bean。 contextConfigLocation 中指定的 bean 会自动在上下文中为您注册。

问题的出现是因为实际上创建了代理的代理。首先为 @Configuration 类创建一个 cglib(基于类的代理)。在此过程中，添加了几个接口(interface)。稍后在基于您的切入点的过程中，将创建另一轮代理，并为 @Configuration 注释的 bean 创建 JDK 动态代理，仅在动态添加的接口(interface)上公开方法，呈现实际方法无法访问。

一个解决方案是修改切入点并排除要检测的 @Configuration 类。