电商平台学习笔记（三）——Mybatis启动异常org.apache.ibatis.type.TypeException

今天一大早刚过来写代码，接着昨天使用MapperScannerConfigurer来扫包！以帮助从DAO层解脱出来（只需要定义接口）！结果就遇到了Bug。

异常内容如下：

java.lang.IllegalStateException: Failed to load ApplicationContext at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:124) at org.springframework.test.context.support.DefaultTestContext.getApplicationContext(DefaultTestContext.java:83) at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.injectDependencies(DependencyInjectionTestExecutionListener.java:117) at org.springframework.test.context.support.DependencyInjectionTestExecutionListener.prepareTestInstance(DependencyInjectionTestExecutionListener.java:83) at org.springframework.test.context.TestContextManager.prepareTestInstance(TestContextManager.java:228) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.createTest(SpringJUnit4ClassRunner.java:230) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner$1.runReflectiveCall(SpringJUnit4ClassRunner.java:289) at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.methodBlock(SpringJUnit4ClassRunner.java:291) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:249) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:89) at org.junit.runners.ParentRunner$3.run(ParentRunner.java:238) at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:63) at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:236) at org.junit.runners.ParentRunner.access$000(ParentRunner.java:53) at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:229) 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:309) at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:193) at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:86) at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:459) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:675) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:382) at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:192) Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'brandServiceImpl': Injection of resource dependencies failed; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'brandDao' defined in file [E:\WorkSpace\NewBaBaSport\BaBaSport\target\classes\cn\ilxy\dao\product\BrandDao.class]: Unsatisfied dependency expressed through bean property 'sqlSessionFactory': Error creating bean with name 'sqlSessionFactory' defined in file [E:\WorkSpace\NewBaBaSport\BaBaSport\target\classes\config\mybatis.xml]: Invocation of init method failed; nested exception is org.apache.ibatis.type.TypeException: The alias 'BrandQuery' is already mapped to the value 'cn.ilxy.query.BrandQuery'.; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sqlSessionFactory' defined in file [E:\WorkSpace\NewBaBaSport\BaBaSport\target\classes\config\mybatis.xml]: Invocation of init method failed; nested exception is org.apache.ibatis.type.TypeException: The alias 'BrandQuery' is already mapped to the value 'cn.ilxy.query.BrandQuery'. at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessPropertyValues(CommonAnnotationBeanPostProcessor.java:311) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1214) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:543) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:772) at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:839) at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:538) at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:125) at org.springframework.test.context.support.AbstractGenericContextLoader.loadContext(AbstractGenericContextLoader.java:60) at org.springframework.test.context.support.AbstractDelegatingSmartContextLoader.delegateLoading(AbstractDelegatingSmartContextLoader.java:109) at org.springframework.test.context.support.AbstractDelegatingSmartContextLoader.loadContext(AbstractDelegatingSmartContextLoader.java:261) at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContextInternal(DefaultCacheAwareContextLoaderDelegate.java:98) at org.springframework.test.context.cache.DefaultCacheAwareContextLoaderDelegate.loadContext(DefaultCacheAwareContextLoaderDelegate.java:116) ... 25 more Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'brandDao' defined in file [E:\WorkSpace\NewBaBaSport\BaBaSport\target\classes\cn\ilxy\dao\product\BrandDao.class]: Unsatisfied dependency expressed through bean property 'sqlSessionFactory': Error creating bean with name 'sqlSessionFactory' defined in file [E:\WorkSpace\NewBaBaSport\BaBaSport\target\classes\config\mybatis.xml]: Invocation of init method failed; nested exception is org.apache.ibatis.type.TypeException: The alias 'BrandQuery' is already mapped to the value 'cn.ilxy.query.BrandQuery'.; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sqlSessionFactory' defined in file [E:\WorkSpace\NewBaBaSport\BaBaSport\target\classes\config\mybatis.xml]: Invocation of init method failed; nested exception is org.apache.ibatis.type.TypeException: The alias 'BrandQuery' is already mapped to the value 'cn.ilxy.query.BrandQuery'. at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireByType(AbstractAutowireCapableBeanFactory.java:1307) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1199) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:543) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:202) at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.autowireResource(CommonAnnotationBeanPostProcessor.java:512) at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.getResource(CommonAnnotationBeanPostProcessor.java:486) at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor$ResourceElement.getResourceToInject(CommonAnnotationBeanPostProcessor.java:615) at org.springframework.beans.factory.annotation.InjectionMetadata$InjectedElement.inject(InjectionMetadata.java:169) at org.springframework.beans.factory.annotation.InjectionMetadata.inject(InjectionMetadata.java:88) at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessPropertyValues(CommonAnnotationBeanPostProcessor.java:308) ... 41 more Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sqlSessionFactory' defined in file [E:\WorkSpace\NewBaBaSport\BaBaSport\target\classes\config\mybatis.xml]: Invocation of init method failed; nested exception is org.apache.ibatis.type.TypeException: The alias 'BrandQuery' is already mapped to the value 'cn.ilxy.query.BrandQuery'. at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1578) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:545) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:482) at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) at org.springframework.beans.factory.support.DefaultListableBeanFactory.findAutowireCandidates(DefaultListableBeanFactory.java:1192) at org.springframework.beans.factory.support.DefaultListableBeanFactory.doResolveDependency(DefaultListableBeanFactory.java:1116) at org.springframework.beans.factory.support.DefaultListableBeanFactory.resolveDependency(DefaultListableBeanFactory.java:1014) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.autowireByType(AbstractAutowireCapableBeanFactory.java:1292) ... 54 more Caused by: org.apache.ibatis.type.TypeException: The alias 'BrandQuery' is already mapped to the value 'cn.ilxy.query.BrandQuery'. at org.apache.ibatis.type.TypeAliasRegistry.registerAlias(TypeAliasRegistry.java:157) at org.apache.ibatis.type.TypeAliasRegistry.registerAlias(TypeAliasRegistry.java:147) at org.apache.ibatis.type.TypeAliasRegistry.registerAliases(TypeAliasRegistry.java:136) at org.mybatis.spring.SqlSessionFactoryBean.buildSqlSessionFactory(SqlSessionFactoryBean.java:395) at org.mybatis.spring.SqlSessionFactoryBean.afterPropertiesSet(SqlSessionFactoryBean.java:355) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1637) at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1574) ... 64 more  

各位看官注意了，凭我看Mybatis这么多的异常的经验来看，一般java.lang.IllegalStateException: Failed to load ApplicationContext异常信息在最上面，多半是你写的配置文件有问题，这次我也是的。我利用Junit测试时，没有调用任何业务逻辑方法时也是报这个错误！

异常信息是说，Spring在扫包时，已经发现BrandQuery别名和cn.ilxy.query.BrandQuery类已经形成了对应关系，在继续扫描的过程中又发现了一个名为BrandQuery的类，故报此异常！后来看了看项目目录（如下图）：

各位看官看明白了没有，出现了两个名为BrandQuery的实体类！故报此异常！

解决方案：每个类名必须是独一无二的！不得重名！相信各位看官知道怎么改了吧！改类名就行了啦！分享出来，希望对各位程序猿对所帮助，少走弯路！

既然选择了远方，就应风雨兼程！ --送给未来最好的自己