一：前沿
2015年新年上班的第二天，第一天就打了一天的醬油哦，只是下午開始搭建自己畢業設計的框架，搭建的是spring+spring mvc+MyBatis的框架。今天遇到了一個問題，結果弄了我一天時間，所以啊，路還是的一步步的走，弄過了才知道是怎么回事。現在記載下這個問題。
二：問題
在自己搭建的時候，我覺得自己一次都沒有去搭建過，所以就想從最簡單的一種開始，所以數據庫連接用的就是org.springframework.jdbc.datasource.DriverManagerDataSource,說白了這種就是沒有數據庫連接池的作用的。
所以現在就說說配置中我自己遇到的問題了。
（1）在啟動tomcat時候一直報DriverManagerDataSource里面的${driver}說加載不了，我就一直以為是由於數據庫連接的問題，就換了使用阿里巴巴的數據庫連接，但是換了之后還是這樣，沒辦法我就想了我剛剛加了一個東西，就是MyBatis和spring結合的配置，配置如下
<!-- 最新的配置方式--> <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer" p:basePackage="com.wuhao.graduate.dao" p:sqlSessionFactoryBeanName="sqlSessionFactory"> </bean> <!-- 以前的配置方式--> <bean class="org.mybatis.spring.mapper.MapperScannerConfigurer"> <property name="basePackage" value="com.wuhao.graduate.dao"></property> <property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"></property> </bean>
但是如果用最新的配置就是可以的，用最原始的配置就是不行，最后才知道原來是sqlSessionFactory這里的配置問題，我個人就覺得那里是要用ref的，但是實際上是用value的，所以一直報下面的錯誤
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.mybatis.spring.mapper.MapperScannerConfigurer#0' defined in class path resource [MyBatis-config.xml]: Cannot resolve reference to bean 'sqlSessionFactory' while setting bean property 'sqlSessionFactoryBeanName'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [MyBatis-config.xml]: Cannot resolve reference to bean 'dataSource' while setting bean property 'dataSource'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [MyBatis-config.xml]: Error setting property values; nested exception is org.springframework.beans.PropertyBatchUpdateException; nested PropertyAccessExceptions (1) are:
PropertyAccessException 1: org.springframework.beans.MethodInvocationException: Property 'driverClassName' threw exception; nested exception is java.lang.IllegalStateException: Could not load JDBC driver class [${driver}]
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:359)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:108)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1471)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1216)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:538)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:302)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:229)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:298)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:198)
at org.springframework.context.support.PostProcessorRegistrationDelegate.invokeBeanFactoryPostProcessors(PostProcessorRegistrationDelegate.java:116)
at org.springframework.context.support.AbstractApplicationContext.invokeBeanFactoryPostProcessors(AbstractApplicationContext.java:606)
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:462)
at org.springframework.web.context.ContextLoader.configureAndRefreshWebApplicationContext(ContextLoader.java:403)
at org.springframework.web.context.ContextLoader.initWebApplicationContext(ContextLoader.java:306)
at org.springframework.web.context.ContextLoaderListener.contextInitialized(ContextLoaderListener.java:106)
at org.apache.catalina.core.StandardContext.listenerStart(StandardContext.java:4994)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5492)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
at org.apache.catalina.core.ContainerBase.addChildInternal(ContainerBase.java:901)
at org.apache.catalina.core.ContainerBase.addChild(ContainerBase.java:877)
at org.apache.catalina.core.StandardHost.addChild(StandardHost.java:649)
at org.apache.catalina.startup.HostConfig.deployDirectory(HostConfig.java:1247)
at org.apache.catalina.startup.HostConfig$DeployDirectory.run(HostConfig.java:1897)
at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:471)
at java.util.concurrent.FutureTask$Sync.innerRun(FutureTask.java:334)
at java.util.concurrent.FutureTask.run(FutureTask.java:166)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:724)
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [MyBatis-config.xml]: Cannot resolve reference to bean 'dataSource' while setting bean property 'dataSource'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [MyBatis-config.xml]: Error setting property values; nested exception is org.springframework.beans.PropertyBatchUpdateException; nested PropertyAccessExceptions (1) are:
PropertyAccessException 1: org.springframework.beans.MethodInvocationException: Property 'driverClassName' threw exception; nested exception is java.lang.IllegalStateException: Could not load JDBC driver class [${driver}]
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:359)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveValueIfNecessary(BeanDefinitionValueResolver.java:108)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1471)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1216)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:538)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:302)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:229)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:298)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:193)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:351)
... 29 more
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'dataSource' defined in class path resource [MyBatis-config.xml]: Error setting property values; nested exception is org.springframework.beans.PropertyBatchUpdateException; nested PropertyAccessExceptions (1) are:
PropertyAccessException 1: org.springframework.beans.MethodInvocationException: Property 'driverClassName' threw exception; nested exception is java.lang.IllegalStateException: Could not load JDBC driver class [${driver}]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1508)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.populateBean(AbstractAutowireCapableBeanFactory.java:1216)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:538)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:476)
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:302)
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:229)
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:298)
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactor
y.java:193)
at org.springframework.beans.factory.support.BeanDefinitionValueResolver.resolveReference(BeanDefinitionValueResolver.java:351)
... 39 more
Caused by: org.springframework.beans.PropertyBatchUpdateException; nested PropertyAccessExceptions (1) are:
PropertyAccessException 1: org.springframework.beans.MethodInvocationException: Property 'driverClassName' threw exception; nested exception is java.lang.IllegalStateException: Could not load JDBC driver class [${driver}]
at org.springframework.beans.AbstractPropertyAccessor.setPropertyValues(AbstractPropertyAccessor.java:121)
at org.springframework.beans.AbstractPropertyAccessor.setPropertyValues(AbstractPropertyAccessor.java:75)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.applyPropertyValues(AbstractAutowireCapableBeanFactory.java:1504)
... 47 more
這種錯誤看着就蛋疼，所以最后百度找了點資料才知道，原來MyBatis的官方文檔上（http://mybatis.github.io/spring/zh/mappers.html#MapperScannerConfigurer）面都說了下面是截圖
（2）第二個小問題就是我再這里指定了要掃描的配置文件
<!-- mybatis文件配置，掃描所有mapper文件 -->
<!-- configLocation為mybatis屬性 mapperLocations為所有mapper-->
<bean id="sqlSessionFactory"
class="org.mybatis.spring.SqlSessionFactoryBean"
p:dataSource-ref="dataSource"
p:configLocation="classpath:Mapper-config.xml"
p:mapperLocations="classpath:Mapper/*.xml">
</bean>
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration> <typeAliases> <typeAlias type="com.duang.haha.vo.User" alias="user"/> </typeAliases> <mappers> <mapper resource="Mapper/User.xml"></mapper> </mappers> </configuration>
現在我來看這個代碼就會覺得
<mappers><mapper resource="Mapper/User.xml"></mapper></mappers>和 p:mapperLocations="classpath:Mapper/*.xml"的配置重復了，但是這樣的配置啟動時會報錯，這使得我很無語啊！
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'sqlSessionFactory' defined in class path resource [MyBatis-config.xml]: Invocation of init method failed; nested exception is org.springframework.core.NestedIOException: Failed to parse mapping resource: 'file [D:\wuhao\java\apache-tomcat-7.0.56\webapps\haha\WEB-INF\classes\Mapper\User.xml]'; nested exception is org.apache.ibatis.builder.BuilderException: Error parsing Mapper XML. Cause: java.lang.IllegalArgumentException: Result Maps collection already contains value for com.wh.haha.dao.UserDao.get_user
所以你需要把Mapper中配置的這個給注掉
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration> <typeAliases> <typeAlias type="com.wh.haha.vo.User" alias="user"/> </typeAliases> <!-- <mappers> <mapper resource="Mapper/User.xml"></mapper> </mappers> --> </configuration>
http://www.cnblogs.com/huanmieuroshui/archive/2012/12/18/2822754.html這篇博客里面說的比較詳細了。
三：總結
自己的畢業設計的框架都搭建起來了，而且測試數據已經可以插入進去，以后每天都搞定一個小功能，一點點的往前走了。加油!畢業設計！終於邁出了第一步啊，這一步花了我兩天時間啊，不過很值得的哦。這幾天呆在公司也沒什么事情，繼續做吧！Go boy !