Spring Data JPA强制将CGLib代理到非存储库类

Question

<jpa:repositories 
    base-package="myapp.persistence.spring" 
    entity-manager-factory-ref="entityManagerFactory"
    transaction-manager-ref="transactionManager" />

Spring开始抱怨：

2012-07-31 16:54:23,153 ERROR [ContextLoader       ] - [Context initialization failed                                                                       ] - [remoteAddress=, remoteHost=, thread=pool-2-thread-1] org.springframework.web.context.ContextLoader
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'companyRepository' defined in file [C:\Development\ApplicationServer\apache-tomcat-7.0.27\webapps\myapp\WEB-INF\classes\myapp\persistence\CompanyRepository.class]: Initialization of bean failed; nested exception is org.springframework.aop.framework.AopConfigException: Cannot proxy target class because CGLIB2 is not available. Add CGLIB to the class path or specify proxy interfaces.
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:527) ~[spring-beans-3.1.2.RELEASE.jar:3.1.2.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:456) ~[spring-beans-3.1.2.RELEASE.jar:3.1.2.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:294) ~[spring-beans-3.1.2.RELEASE.jar:3.1.2.RELEASE]
    at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:225) ~[spring-beans-3.1.2.RELEASE.jar:3.1.2.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:291) ~[spring-beans-3.1.2.RELEASE.jar:3.1.2.RELEASE]
    at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193) ~[spring-beans-3.1.2.RELEASE.jar:3.1.2.RELEASE]
    at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:609) ~[spring-beans-3.1.2.RELEASE.jar:3.1.2.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:918) ~[spring-context-3.1.2.RELEASE.jar:3.1.2.RELEASE]
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:469) ~[spring-context-3.1.2.RELEASE.jar:3.1.2.RELEASE]
    at org.springframework.web.context.ContextLoader.createWebApplicationContext(ContextLoader.java:282) ~[spring-web-3.0.7.RELEASE.jar:3.0.7.RELEASE]
    at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:204) ~[spring-web-3.0.7.RELEASE.jar:3.0.7.RELEASE]
    at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:47) [spring-web-3.0.7.RELEASE.jar:3.0.7.RELEASE]
    at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4779) [catalina.jar:7.0.27]
    at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5273) [catalina.jar:7.0.27]
    at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150) [catalina.jar:7.0.27]
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1566) [catalina.jar:7.0.27]
    at org.apache.catalina.core.ContainerBase$StartChild.call(ContainerBase.java:1556) [catalina.jar:7.0.27]
    at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:303) [na:1.6.0_24]
    at java.util.concurrent.FutureTask.run(FutureTask.java:138) [na:1.6.0_24]
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:886) [na:1.6.0_24]
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:908) [na:1.6.0_24]
    at java.lang.Thread.run(Thread.java:662) [na:1.6.0_24]
Caused by: org.springframework.aop.framework.AopConfigException: Cannot proxy target class because CGLIB2 is not available. Add CGLIB to the class path or specify proxy interfaces.
    at org.springframework.aop.framework.DefaultAopProxyFactory.createAopProxy(DefaultAopProxyFactory.java:67) ~[spring-aop-3.1.2.RELEASE.jar:3.1.2.RELEASE]
    at org.springframework.aop.framework.ProxyCreatorSupport.createAopProxy(ProxyCreatorSupport.java:104) ~[spring-aop-3.1.2.RELEASE.jar:3.1.2.RELEASE]
    at org.springframework.aop.framework.ProxyFactory.getProxy(ProxyFactory.java:112) ~[spring-aop-3.1.2.RELEASE.jar:3.1.2.RELEASE]
    at org.springframework.dao.annotation.PersistenceExceptionTranslationPostProcessor.postProcessAfterInitialization(PersistenceExceptionTranslationPostProcessor.java:133) ~[spring-tx-3.1.2.RELEASE.jar:3.1.2.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsAfterInitialization(AbstractAutowireCapableBeanFactory.java:407) ~[spring-beans-3.1.2.RELEASE.jar:3.1.2.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1461) ~[spring-beans-3.1.2.RELEASE.jar:3.1.2.RELEASE]
    at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:519) ~[spring-beans-3.1.2.RELEASE.jar:3.1.2.RELEASE]
    ... 21 common frames omitted

注意，Spring数据被配置为扫描包myapp.persistence.Spring，而上面的错误引用了包myapp.persistence中的一个类。当我将CGlib添加到项目中时，包括Spring数据在内的一切都可以正常工作。但是发生了什么？我是一个Spring菜鸟，相当困惑。我不知道Spring Data是如何实现代理魔法的。至少官方的例子根本不包括CGlib。进一步资料：

CompanyRepository是一个使用EntityManager自制的简单JPA-DAO：

@Repository
@Transactional(propagation = Propagation.MANDATORY)
public class CompanyRepository extends AbstractRepository<Company, Long> {
  …
}

<tx:annotation-driven proxy-target-class="true" mode="aspectj"/>
<bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
    <property name="entityManagerFactory" ref="entityManagerFactory" />
</bean>

Answer 1

如参考文档中所述，使用 激活用@repository注释的Spring bean的持久性异常转换。对于@repository的JavaDoc来说，注释的主要目的是将异常转换应用于用它注释的组件。如果您的类实现了接口，则可以使用普通JDK代理。如果不是这样，就需要CGLib来创建代理。Spring参考文档中有更多详细信息。

要在不使用CGLib的情况下使用 ，在您的场景中有两种选择：

1. 为每个用@repository注释的组件引入一个接口。这仍将应用持久性异常转换，这可能是您所希望的。
2. 首先不是使用@repository，而是使用@component来禁用这些组件的异常转换。