mybatis重复扫描package的问题

    今天修改了一些东西后，发现web项目启动不了了。日志中出现504组如下的日志，都是mybatis打印的，扫描jar，解析dao，mapping文件等信息。费了半天劲，也没有找到问题。因为这些全是debug级别的，我就没有在意。后来发现每组的最后一条信息"Ignoring bean creation exception..."，有错误信息，才发现问题的根源是mybatis的mapping.xml文件中，语句的id重复了。

   可问题是
          1.为什么会打印这么多重复的日志呢？

          2.为什么只有debug级别的日志呢？

 

问题1：

    通过对日志 和源码的学习，终于把第一问题解答了。

    1). dao类是需要注入一个SqlSessionFactory的。mybatis与spring整合，对应的是SqlSessionFactoryBean类。

    2). SqlSessionFactoryBean在创建的时候，会加载所有的mapping文件。

    3). 当加载失败的时候，不会抛出异常，只是打印了一个debug级别的日志。刚才提到的"Ignoring bean creation exception..."信息。

        所以程序会继续进行。

   

    4). 然后，当每次需要注入“依赖 [此SqlSessionFactoryBean类] 的Dao类”的时候，就会打印一组 3)中的错误信息。

        so，当有很多类依赖这些Dao的时候，就有了这504组错误信息。。

 

问题2：

      查看了所有的日志，发现只有这一行信息能够清楚的说明问题的原因。这一行信息是由spring记录的。( org.springframework.beans.factory.support.AbstractBeanFactory#getTypeForFactoryBean )

      估计他并不想直接吞掉这个异常，因为把这个Exception放入了suppressedExceptions属性里，可能会在必要的时候统一抛出。

      可是，在这种情况下，他并没有抛出正确的异常。不知算不算mybatis-spring的bug。总之，这种编程问题，在测试环境下，就可以发现，不会影响生产环境，所以问题也不大。不过这种处理方式，错信息混杂在debug级别的信息中，确实不太好定位问题。

 

 

 

附两组日志：

DEBUG DefaultListableBeanFactory - Creating shared instance of singleton bean 'tradeShareDao'
DEBUG DefaultListableBeanFactory - Creating instance of bean 'tradeShareDao'
DEBUG DefaultListableBeanFactory - Eagerly caching bean 'tradeShareDao' to allow for resolving potential circular references
DEBUG DefaultListableBeanFactory - Creating shared instance of singleton bean 'settlementSqlSessionFactory'
DEBUG DefaultListableBeanFactory - Creating instance of bean 'settlementSqlSessionFactory'
DEBUG DefaultListableBeanFactory - Eagerly caching bean 'settlementSqlSessionFactory' to allow for resolving potential circular references
DEBUG DefaultListableBeanFactory - Returning cached instance of singleton bean 'settlementDataSource'
DEBUG PathMatchingResourcePatternResolver - Looking for matching resources in jar file [file:/xxxx/webapps/management/WEB-INF/lib/xxx-settlement-orm-1.0-SNAPSHOT.jar]
DEBUG PathMatchingResourcePatternResolver - Resolved location pattern [classpath:settlement_mapper/*Mapper.xml] to resources [class path resource [settlement_mapper/PaymentTypeMapper.xml], class path resource [settlement_mapper/TradeShareMapper.xml]]
DEBUG DefaultListableBeanFactory - Invoking afterPropertiesSet() on bean with name 'settlementSqlSessionFactory'
DEBUG ResolverUtil - Find JAR URL: jar:file:/xxxx/webapps/management/WEB-INF/lib/xxx-settlement-orm-1.0-SNAPSHOT.jar!/com/test/settlement/orm/
DEBUG ResolverUtil - Inner URL: file:/xxxx/webapps/management/WEB-INF/lib/xxx-settlement-orm-1.0-SNAPSHOT.jar!/com/test/settlement/orm/
DEBUG ResolverUtil - Extracted JAR URL: file:/xxxx/webapps/management/WEB-INF/lib/xxx-settlement-orm-1.0-SNAPSHOT.jar
DEBUG ResolverUtil - Found JAR: file:/xxxx/webapps/management/WEB-INF/lib/xxx-settlement-orm-1.0-SNAPSHOT.jar
DEBUG ResolverUtil - Listing jar:file:/xxxx/webapps/management/WEB-INF/lib/xxx-settlement-orm-1.0-SNAPSHOT.jar!/com/test/settlement/orm/
DEBUG ResolverUtil - Found resource: /com/test/settlement/orm/dao/TradeShareDao.class
DEBUG ResolverUtil - Found resource: /com/test/settlement/orm/dao/PaymentTypeDao.class
DEBUG ResolverUtil - Checking to see if class com.test.settlement.orm.dao.TradeShareDao matches criteria [is assignable to Object]
DEBUG ResolverUtil - Checking to see if class com.test.settlement.orm.dao.PaymentTypeDao matches criteria [is assignable to Object]
DEBUG DefaultListableBeanFactory - Ignoring bean creation exception on FactoryBean type check: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'tradeShareDao' defined in URL [jar:file:/xxxx/webapps/management/WEB-INF/lib/xxx-settlement-orm-1.0-SNAPSHOT.jar!/com/test/settlement/orm/dao/TradeShareDao.class]: Cannot resolve reference to bean 'settlementSqlSessionFactory' while setting bean property 'sqlSessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'settlementSqlSessionFactory' defined in class path resource [applicationContext-db-settlement.xml]: Invocation of init method failed; nested exception is org.springframework.core.NestedIOException: Failed to parse mapping resource: 'class path resource [settlement_mapper/manual-SettleItemMapper.xml]'; nested exception is org.apache.ibatis.builder.BuilderException: Error parsing Mapper XML. Cause: java.lang.IllegalArgumentException: XML fragments parsed from previous mappers already contains value for com.test.settlement.orm.dao.SettleItemDao.SettleItem_columns


DEBUG DefaultListableBeanFactory - Creating shared instance of singleton bean 'paymentTypeDao'
DEBUG DefaultListableBeanFactory - Creating instance of bean 'paymentTypeDao'
DEBUG DefaultListableBeanFactory - Eagerly caching bean 'paymentTypeDao' to allow for resolving potential circular references
DEBUG DefaultListableBeanFactory - Creating shared instance of singleton bean 'settlementSqlSessionFactory'
DEBUG DefaultListableBeanFactory - Creating instance of bean 'settlementSqlSessionFactory'
DEBUG DefaultListableBeanFactory - Eagerly caching bean 'settlementSqlSessionFactory' to allow for resolving potential circular references
DEBUG DefaultListableBeanFactory - Returning cached instance of singleton bean 'settlementDataSource'
DEBUG PathMatchingResourcePatternResolver - Looking for matching resources in jar file [file:/xxxx/webapps/management/WEB-INF/lib/xxx-settlement-orm-1.0-SNAPSHOT.jar]
DEBUG PathMatchingResourcePatternResolver - Resolved location pattern [classpath:settlement_mapper/*Mapper.xml] to resources [class path resource [settlement_mapper/PaymentTypeMapper.xml], class path resource [settlement_mapper/TradeShareMapper.xml]]
DEBUG DefaultListableBeanFactory - Invoking afterPropertiesSet() on bean with name 'settlementSqlSessionFactory'
DEBUG ResolverUtil - Find JAR URL: jar:file:/xxxx/webapps/management/WEB-INF/lib/xxx-settlement-orm-1.0-SNAPSHOT.jar!/com/test/settlement/orm/
DEBUG ResolverUtil - Inner URL: file:/xxxx/webapps/management/WEB-INF/lib/xxx-settlement-orm-1.0-SNAPSHOT.jar!/com/test/settlement/orm/
DEBUG ResolverUtil - Extracted JAR URL: file:/xxxx/webapps/management/WEB-INF/lib/xxx-settlement-orm-1.0-SNAPSHOT.jar
DEBUG ResolverUtil - Found JAR: file:/xxxx/webapps/management/WEB-INF/lib/xxx-settlement-orm-1.0-SNAPSHOT.jar
DEBUG ResolverUtil - Listing jar:file:/xxxx/webapps/management/WEB-INF/lib/xxx-settlement-orm-1.0-SNAPSHOT.jar!/com/test/settlement/orm/
DEBUG ResolverUtil - Found resource: /com/test/settlement/orm/dao/TradeShareDao.class
DEBUG ResolverUtil - Found resource: /com/test/settlement/orm/dao/PaymentTypeDao.class
DEBUG ResolverUtil - Checking to see if class com.test.settlement.orm.dao.TradeShareDao matches criteria [is assignable to Object]
DEBUG ResolverUtil - Checking to see if class com.test.settlement.orm.dao.PaymentTypeDao matches criteria [is assignable to Object]
DEBUG DefaultListableBeanFactory - Ignoring bean creation exception on FactoryBean type check: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'paymentTypeDao' defined in URL [jar:file:/xxxx/webapps/management/WEB-INF/lib/xxx-settlement-orm-1.0-SNAPSHOT.jar!/com/test/settlement/orm/dao/PaymentTypeDao.class]: Cannot resolve reference to bean 'settlementSqlSessionFactory' while setting bean property 'sqlSessionFactory'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'settlementSqlSessionFactory' defined in class path resource [applicationContext-db-settlement.xml]: Invocation of init method failed; nested exception is org.springframework.core.NestedIOException: Failed to parse mapping resource: 'class path resource [settlement_mapper/manual-SettleItemMapper.xml]'; nested exception is org.apache.ibatis.builder.BuilderException: Error parsing Mapper XML. Cause: java.lang.IllegalArgumentException: XML fragments parsed from previous mappers already contains value for com.test.settlement.orm.dao.SettleItemDao.SettleItem_columns