为什么我需要cglib（SpringAOP）来拥有多个测试类？

我有一个spring应用程序 我的测试课程如下：

@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = { "classpath:/META-INF/spring/applicationContext.xml" })
@TransactionConfiguration(defaultRollback = true)
@Transactional
public class MyTest {

}

当我尝试创建另一个测试类并尝试运行应用程序时，新测试类出现以下异常：

ERROR [main] (TestContextManager.java:324) - Caught exception while allowing TestExecutionListener [org.springframework.test.context.support.DependencyInjectionTestExecut
r@22e85825] to prepare test instance [Testing.MyTest2@43f2f70a]
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)
        at org.springframework.aop.framework.ProxyCreatorSupport.createAopProxy(ProxyCreatorSupport.java:104)
        at org.springframework.aop.framework.ProxyFactory.getProxy(ProxyFactory.java:112)
        at org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator.createProxy(AbstractAutoProxyCreator.java:476)
        at org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator.wrapIfNecessary(AbstractAutoProxyCreator.java:362)
        at org.springframework.aop.framework.autoproxy.AbstractAutoProxyCreator.postProcessAfterInitialization(AbstractAutoProxyCreator.java:322)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyBeanPostProcessorsAfterInitialization(AbstractAutowireCapableBeanFactory.java
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1426)
        at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:386)
        at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:111)
        at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:75)
        at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:321)
        at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:220)
        at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:301)
        at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
        at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:303)
        at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:240)
        at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:50)
        at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
        at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
        at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
        at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
        at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
        at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
        at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:70)
        at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
        at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:180)
        at org.apache.maven.surefire.junit4.JUnit4TestSet.execute(JUnit4TestSet.java:62)
        at org.apache.maven.surefire.suite.AbstractDirectoryTestSuite.executeTestSet(AbstractDirectoryTestSuite.java:140)
        at org.apache.maven.surefire.suite.AbstractDirectoryTestSuite.execute(AbstractDirectoryTestSuite.java:127)
        at org.apache.maven.surefire.Surefire.run(Surefire.java:177)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
        at java.lang.reflect.Method.invoke(Method.java:597)
        at org.apache.maven.surefire.booter.SurefireBooter.runSuitesInProcess(SurefireBooter.java:345)
        at org.apache.maven.surefire.booter.SurefireBooter.main(SurefireBooter.java:1009)

通过向我的类路径添加cglib解决了这个异常，但我想了解为什么多个测试类需要cglib

---

请告知，谢谢。

我猜spring在运行时将其添加到您的类中，这就是为什么它需要cglib库（用于字节码操作和代码注入，请参阅）

spring需要cglib JAR，因为它使用cglib代理您的bean。如果将spring配置为在applicationContext.xml中使用此机制，或者spring需要代理一个不实现接口的类，则会发生这种情况。Spring文档对此进行了详细介绍，并提供了非常清晰的解释

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为了使用JDK动态代理，请确保任何代理类都实现了适当的接口，并且您没有通过配置强制Spring使用CGLIB。

Spring肯定会为您的一些类使用代理机制

但是，从SpringVersion3.2开始，默认情况下会将和添加到SpringCore中，因此不需要手动将CGLIB库添加到类路径中

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顺便说一句，正如Michael Isvy和state所说，CGLIB项目不再处于活动状态。在未来的版本中，Spring将默认使用Javassist。

您的“另一个测试”是否使用相同的

applicationContext.xml

？是的，因为我需要两个测试使用applicationContext.xml中存在的相同数据库配置。需要CGLIB“如果Spring需要代理一个不实现接口的类”对我来说是个新闻。谢谢