業務類沒法被AOP代理問題

時間  2019-11-16
標籤 業務 沒法 aop 代理 問題 简体版
原文   原文鏈接

背景

在項目裏面引入了shiro框架，然而在用戶登陸的時候始終會出現數據庫訪問異常，異常信息以下：java

從異常日誌來看是找錯了數據庫，由於項目中使用了多數據源技術，經過在service層加上@DS(Database.DATABASE_CA_SYSTEM)註解來標示該service須要使用哪一個數據源。這個異常說明註解並無實現它該有的做用。web

多數據源使用的是baomidou開發的框架,相關依賴以下，它的核心是經過AOP技術來切換每一個service須要使用的數據源，具體實現這裏先不討論。spring

<dependency>    
    <groupId>com.baomidou</groupId>    
    <artifactId>dynamic-datasource-spring-boot-starter</artifactId> 		    
</dependency>
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上面的異常說明userService這個bean並無被代理，那麼問題出來哪裏呢？數據庫

問題定位

springboot的啓動日誌中發現一個值得注意的點：apache

Warn: Could not find @TableId in Class: com.greenet.platform.common.entity.User. 2019-11-14 15:50:42.487 INFO 17752 --- [ main] trationDelegateBeanPostProcessorChecker : Bean 'userMapper' of type [org.mybatis.spring.mapper.MapperFactoryBean] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying) 2019-11-14 15:50:42.489 INFO 17752 --- [ main] trationDelegateBeanPostProcessorChecker : Bean 'userMapper' of type [com.sun.proxy.Proxy64] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying) 2019-11-14 15:50:42.490 INFO 17752 --- [ main] trationDelegateBeanPostProcessorChecker : Bean 'userService' of type [com.greenet.platform.common.service.impl.UserServiceImpl] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying) 2019-11-14 15:50:42.555 INFO 17752 --- [ main] trationDelegate$BeanPostProcessorChecker : Bean 'cacheManager' of type [org.apache.shiro.cache.ehcache.EhCacheManager] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying) 2019-11-14 15:50:42.556 INFO 17752 --- [ main] o.a.shiro.cache.ehcache.EhCacheManager : Using existing EHCache named [passwordRetryCache安全

重點在這句話：springboot

trationDelegate$BeanPostProcessorChecker : Bean 'userService' of type [com.greenet.platform.common.service.impl.UserServiceImpl] is not eligible for getting processed by all BeanPostProcessors (for example: not eligible for auto-proxying)bash

這句話意思是userService因爲不符合某種條件，致使不會被自動代理，那麼這個條件是什麼呢？session

查看BeanPostProcessorChecker的源碼，打印日誌的地方以下：mybatis

@Overridepublic Object postProcessAfterInitialization(Object bean, String beanName) {   
    if (!(bean instanceof BeanPostProcessor) && !isInfrastructureBean(beanName) &&         this.beanFactory.getBeanPostProcessorCount() < this.beanPostProcessorTargetCount) {      
        if (logger.isInfoEnabled()) {    
            logger.info("Bean '" + beanName + "' of type [" + bean.getClass().getName() +               "] is not eligible for getting processed by all BeanPostProcessors " +               "(for example: not eligible for auto-proxying)");      }   }   
    return bean;
}
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日誌打印出來的緣由是this.beanFactory.getBeanPostProcessorCount() < this.beanPostProcessorTargetCount返回了true,也就是說此時註冊到beanFactory的後置處理器數量是少於總的後置處理器數量的，也就是說這個時候有其餘後置處理器還沒準備好，userService就已經被實例化了;

既然這個地方說了userService不會被代理，那麼這個bean又是在何時被spring實例化的呢。想搞清楚這個問題很簡單，能夠在AbstractBeanFactory.doGetBean方法裏面打一個條件斷點，而後看調用棧。

獲得以下調用棧：

"main@1" prio=5 tid=0x1 nid=NA runnable
  java.lang.Thread.State: RUNNABLE
	  at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:242)
	  at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
	  at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:277)
	  at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1247)
	  at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1167)
	  at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:857)
	  at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:760)
	  at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:509)
	  at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1305)
	  at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1144)
	  at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555)
	  at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515)
	  at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320)
	  at org.springframework.beans.factory.support.AbstractBeanFactory$$Lambda$121.1862994526.getObject(Unknown Source:-1)
	  at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
	  - locked <0x12b7> (a java.util.concurrent.ConcurrentHashMap)
	  at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318)
	  at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
	  at org.springframework.beans.factory.config.DependencyDescriptor.resolveCandidate(DependencyDescriptor.java:277)
	  at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1247)
	  at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1167)
	  at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:857)
	  at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:760)
	  at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:509)
	  at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1305)
	  at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1144)
	  at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.getSingletonFactoryBeanForTypeCheck(AbstractAutowireCapableBeanFactory.java:991)
	  at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.getTypeForFactoryBean(AbstractAutowireCapableBeanFactory.java:865)
	  at org.springframework.beans.factory.support.AbstractBeanFactory.isTypeMatch(AbstractBeanFactory.java:574)
	  at org.springframework.beans.factory.support.DefaultListableBeanFactory.doGetBeanNamesForType(DefaultListableBeanFactory.java:514)
	  at org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanNamesForType(DefaultListableBeanFactory.java:477)
	  at org.springframework.beans.factory.BeanFactoryUtils.beanNamesForTypeIncludingAncestors(BeanFactoryUtils.java:227)
	  at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1411)
	  at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1210)
	  at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1167)
	  at org.springframework.beans.factory.support.ConstructorResolver.resolveAutowiredArgument(ConstructorResolver.java:857)
	  at org.springframework.beans.factory.support.ConstructorResolver.createArgumentArray(ConstructorResolver.java:760)
	  at org.springframework.beans.factory.support.ConstructorResolver.instantiateUsingFactoryMethod(ConstructorResolver.java:509)
	  at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.instantiateUsingFactoryMethod(AbstractAutowireCapableBeanFactory.java:1305)
	  at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBeanInstance(AbstractAutowireCapableBeanFactory.java:1144)
	  at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555)
	  at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:515)
	  at org.springframework.beans.factory.support.AbstractBeanFactory.lambda$doGetBean$0(AbstractBeanFactory.java:320)
	  at org.springframework.beans.factory.support.AbstractBeanFactory$$Lambda$121.1862994526.getObject(Unknown Source:-1)
	  at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:222)
	  at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:318)
	  at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:204)
	  at org.springframework.context.support.PostProcessorRegistrationDelegate.registerBeanPostProcessors(PostProcessorRegistrationDelegate.java:228)
	  at org.springframework.context.support.AbstractApplicationContext.registerBeanPostProcessors(AbstractApplicationContext.java:721)
	  at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:534)
	  - locked <0x12ea> (a java.lang.Object)
	  at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:142)
	  at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:775)
	  at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:397)
	  at org.springframework.boot.SpringApplication.run(SpringApplication.java:316)
	  at org.springframework.boot.SpringApplication.run(SpringApplication.java:1260)
	  at org.springframework.boot.SpringApplication.run(SpringApplication.java:1248)
	  at com.greenet.platform.Application.main(Application.java:24)

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從調用棧能夠看到兩個重點信息：

  • 這個棧裏面出現了三次AbstractBeanFactory.doGetBean，
  • 棧的入口是 AbstractApplicationContext.registerBeanPostProcessors

這兩點說明userService不是在正常的AbstractApplicationContext.finishBeanFactoryInitialization階段經過實例化，而是在註冊後置處理器的時候就實例化了。

爲何會提早實例化呢？

MethodValidationPostProcessor

從上面打的斷點回頭追溯到registerBeanPostProcessors的地方，能夠看到此時註冊的後置處理器MethodValidationPostProcessor，調試截圖以下：

是對應的代碼以下：

for (String ppName : orderedPostProcessorNames) {
			BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
			orderedPostProcessors.add(pp);
			if (pp instanceof MergedBeanDefinitionPostProcessor) {
				internalPostProcessors.add(pp);
			}
		}
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也就是說userService在MethodValidationPostProcessor這個後置處理器註冊前的實例化的過程當中，由於某種緣由被提早實例化了。

那麼究竟是爲啥實例化MethodValidationPostProcessor的時候須要實例化userService呢

經過一波調試發現，問題出來個人shiro配置裏面

@Bean("securityManager")
    public SecurityManager securityManager(UserRealm userRealm, SessionManager sessionManager, EhCacheManager cacheManager) {
        DefaultWebSecurityManager securityManager = new DefaultWebSecurityManager();
        securityManager.setRealm(userRealm);
        securityManager.setSessionManager(sessionManager);
        securityManager.setRememberMeManager(null);
        securityManager.setCacheManager(cacheManager);
        return securityManager;
    }


    /** * shiro權限驗證 * * @param securityManager 安全管理器 * @return 安全管理factorybean */
    @Bean("shiroFilter")
    public ShiroFilterFactoryBean shiroFilter(SecurityManager securityManager) {
        ShiroFilterFactoryBean shiroFilter = new ShiroFilterFactoryBean();
        shiroFilter.setSecurityManager(securityManager);
        shiroFilter.setLoginUrl("/login");

        Map<String, String> filterMap = new LinkedHashMap<>();

        filterMap.put("/static/**", "anon");
        filterMap.put("/", "anon");
        filterMap.put("/login/getVerifyCodeImage", "anon");

        filterMap.put("/**", "authc");
        shiroFilter.setFilterChainDefinitionMap(filterMap);

        return shiroFilter;
    }
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罪魁禍首是這個ShiroFilterFactoryBean，這個東西的定義以下：

public class ShiroFilterFactoryBean implements FactoryBean, BeanPostProcessor {
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它實現了FactoryBean, BeanPostProcessor這兩個特殊的接口，全部的FactoryBean會在後置處理器MethodValidationPostProcessor實例化過程當中被實例化，爲啥呢，這跟這個後置處理器的定義的地方有關係，這個後置處理器在ValidationAutoConfiguration類中定義，具體方法代碼以下：

@Bean
	@ConditionalOnMissingBean
	public static MethodValidationPostProcessor methodValidationPostProcessor(
			Environment environment, @Lazy Validator validator) {
		MethodValidationPostProcessor processor = new MethodValidationPostProcessor();
		boolean proxyTargetClass = environment
				.getProperty("spring.aop.proxy-target-class", Boolean.class, true);
		processor.setProxyTargetClass(proxyTargetClass);
		processor.setValidator(validator);
		return processor;
	}
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想要實例化這個類，須要指導這個方法的參數，問題就出在這個Environment裏面，爲了找到類型爲Environment的參數，spring會遍歷整個beanDefinitionNames，而後去找到符合Environment這個類型的bean，找的過程當中發現有些bean是factoryBean，那很差意思，須要把這個factoryBean給實例化出來，再看上面ShiroFilterFactoryBean定義的方法能夠看到，它依賴了securityManager，而securityManager又依賴了userRealm，而userRealm有依賴了userService:

@Component
public class UserRealm extends AuthorizingRealm {

    private static final String ACCOUNT_TYPE_WEB = "2";
    private static final String ACCOUNT_TYPE_ALL = "255";

    @Autowired
    UserService userService;
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就這樣一步步把userService給實例化了，這個時候還沒到後置處理器處理bean的時候，那負責作AOP代理的後置處理器天然沒法再去處理userService了。

解決方案

那麼如何去解決這個問題呢，思路是不要在factoryBean裏面去注入業務類，一種比較簡單的辦法是去注入ApplicationContext，而後經過getBean方法拿到業務的service

private UserService getUserService() {
        return (UserService) applicationContext.getBean("userService");
    }
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