业务类没法被AOP代理问题

时间 2019-11-16

标签业务没法 aop 代理问题繁體版

原文原文链接

背景

在项目里面引入了shiro框架，然而在用户登陆的时候始终会出现数据库访问异常，异常信息以下：java

从异常日志来看是找错了数据库，由于项目中使用了多数据源技术，经过在service层加上@DS(Database.DATABASE_CA_SYSTEM)注解来标示该service须要使用哪一个数据源。这个异常说明注解并无实现它该有的做用。web

多数据源使用的是baomidou开发的框架,相关依赖以下，它的核心是经过AOP技术来切换每一个service须要使用的数据源，具体实现这里先不讨论。spring

<dependency>    
    <groupId>com.baomidou</groupId>    
    <artifactId>dynamic-datasource-spring-boot-starter</artifactId> 		    
</dependency>
复制代码

上面的异常说明userService这个bean并无被代理，那么问题出来哪里呢？数据库

问题定位

springboot的启动日志中发现一个值得注意的点：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 [com.sun.proxy.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) 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

重点在这句话：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

这句话意思是userService因为不符合某种条件，致使不会被自动代理，那么这个条件是什么呢？session

查看BeanPostProcessorChecker的源码，打印日志的地方以下：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;
}
复制代码

日志打印出来的缘由是this.beanFactory.getBeanPostProcessorCount() < this.beanPostProcessorTargetCount返回了true,也就是说此时注册到beanFactory的后置处理器数量是少于总的后置处理器数量的，也就是说这个时候有其余后置处理器还没准备好，userService就已经被实例化了;

既然这个地方说了userService不会被代理，那么这个bean又是在何时被spring实例化的呢。想搞清楚这个问题很简单，能够在AbstractBeanFactory.doGetBean方法里面打一个条件断点，而后看调用栈。

获得以下调用栈：

"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)

复制代码

从调用栈能够看到两个重点信息：

这个栈里面出现了三次AbstractBeanFactory.doGetBean，
栈的入口是 AbstractApplicationContext.registerBeanPostProcessors

这两点说明userService不是在正常的AbstractApplicationContext.finishBeanFactoryInitialization阶段经过实例化，而是在注册后置处理器的时候就实例化了。

为何会提早实例化呢？

`MethodValidationPostProcessor`

从上面打的断点回头追溯到registerBeanPostProcessors的地方，能够看到此时注册的后置处理器MethodValidationPostProcessor，调试截图以下：

是对应的代码以下：

for (String ppName : orderedPostProcessorNames) {
			BeanPostProcessor pp = beanFactory.getBean(ppName, BeanPostProcessor.class);
			orderedPostProcessors.add(pp);
			if (pp instanceof MergedBeanDefinitionPostProcessor) {
				internalPostProcessors.add(pp);
			}
		}
复制代码

也就是说userService在MethodValidationPostProcessor这个后置处理器注册前的实例化的过程当中，由于某种缘由被提早实例化了。

那么究竟是为啥实例化MethodValidationPostProcessor的时候须要实例化userService呢

经过一波调试发现，问题出来个人shiro配置里面

@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权限验证 * * @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;
    }
复制代码

罪魁祸首是这个ShiroFilterFactoryBean，这个东西的定义以下：

public class ShiroFilterFactoryBean implements FactoryBean, BeanPostProcessor {
复制代码

它实现了FactoryBean, BeanPostProcessor这两个特殊的接口，全部的FactoryBean会在后置处理器MethodValidationPostProcessor实例化过程当中被实例化，为啥呢，这跟这个后置处理器的定义的地方有关系，这个后置处理器在ValidationAutoConfiguration类中定义，具体方法代码以下：

@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;
	}
复制代码

想要实例化这个类，须要指导这个方法的参数，问题就出在这个Environment里面，为了找到类型为Environment的参数，spring会遍历整个beanDefinitionNames，而后去找到符合Environment这个类型的bean，找的过程当中发现有些bean是factoryBean，那很差意思，须要把这个factoryBean给实例化出来，再看上面ShiroFilterFactoryBean定义的方法能够看到，它依赖了securityManager，而securityManager又依赖了userRealm，而userRealm有依赖了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;
复制代码

就这样一步步把userService给实例化了，这个时候还没到后置处理器处理bean的时候，那负责作AOP代理的后置处理器天然没法再去处理userService了。

解决方案

那么如何去解决这个问题呢，思路是不要在factoryBean里面去注入业务类，一种比较简单的办法是去注入ApplicationContext，而后经过getBean方法拿到业务的service

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