公司更改项目框架时,处理CLOB字段曾经出过一个问题。今天抽时间整理个大概出来。以下是老框架的配置。
Ibatis配置文件:
<sqlMapConfig> <settings cacheModelsEnabled="true" enhancementEnabled="true" lazyLoadingEnabled="false" maxRequests="6000" maxSessions="5000" maxTransactions="2000" useStatementNamespaces="true" /> <typeHandler jdbcType="BLOB" javaType="[B" callback="org.springframework.orm.ibatis.support.BlobByteArrayTypeHandler" /> <typeHandler jdbcType="CLOB" javaType="java.lang.String" callback="org.springframework.orm.ibatis.support.ClobStringTypeHandler" /> <typeHandler jdbcType="DATETIME" javaType="java.util.Date" callback="com.**.ibatis.patch.typehandler.DateTimeTypeHandlerCallback" /> <!-- generate start --> maps_xml_generate <!-- generate end --> </sqlMapConfig> map映射文件中: <resultMap id="abatorgenerated_PayOrderInfoResultWithBLOBs" class="com.**.entity.PayOrderInfo" extends="PAY_ORDER_INFO.abatorgenerated_PayOrderInfoResult" > <!-- WARNING - This element is automatically generated by Abator for iBATIS, do not modify. --> <result column="REQUEST_DATA" property="requestData" jdbcType="CLOB" /> </resultMap>
spring配置文件:
<!-- SqlMap setup for iBATIS Database Layer --> <bean id="sqlMapClient" class="com.**.ibatis.patch.spring.SqlMapClientFactoryBean"> <property name="configLocations"> <list> <value>classpath:/META-INF/sql-map-config.xml</value> <value>classpath:/META-INF/sql-map-config-front.xml</value> </list> </property> <property name="dataSource" ref="dataSource" /> <property name="lobHandler" ref="lobHandler"></property> <property name="sqlExecutor" ref="sqlExecutor"></property> </bean> <!--Blob field hander for Oracle9i or Oracle10g --> <bean id="nativeJdbcExtractor" class="org.springframework.jdbc.support.nativejdbc.CommonsDbcpNativeJdbcExtractor" lazy-init="true" /> <bean id="lobHandler" class="org.springframework.jdbc.support.lob.OracleLobHandler" lazy-init="true"> <property name="nativeJdbcExtractor" ref="nativeJdbcExtractor" /> </bean>
看过一些介绍,说的是OracleLobHandler能处理oracle9i及其以上版本的CLOB字段。但是在新框架中同样的配置,查询时没有问题,插入CLOB字段时却失败,这里由于是很久前出的问题,没有错误日志可贴。后来解决办法如下:
<!--Blob field hander for Oracle9i or Oracle10g --> <bean id="nativeJdbcExtractor" class="org.springframework.jdbc.support.nativejdbc.CommonsDbcpNativeJdbcExtractor" lazy-init="true" /> <bean id="lobHandler" class="org.springframework.jdbc.support.lob.DefaultLobHandler" lazy-init="true"> <!--这里去掉了nativeJdbcExtractor转换器--> <!-- <property name="nativeJdbcExtractor" ref="nativeJdbcExtractor" /> --> </bean>
这样就解决了blob和clob字段的插入问题。但是对于为什么不能用OracleLobHandler并没有找到原因。最后总结可能是Spring版本问题(新框架版本为4.0.3,老框架2.5.5),但是目前为止没有找到相关说明。这里注意必须在事务下操作clob字段。原因不明。。
springAPI文档中DefaultLobHandler介绍为:This does not apply to Oracle 9i, and only to a limited degree to Oracle 10g!
OracleLobHandler介绍为:Note that this LobHandler requires Oracle JDBC driver 9i or higher!
Spring内置提供的NativeJdbcExtractor转换器有:
C3P0NativeJdbcExtractor
CommonsDbcpNativeJdbcExtractor
JBossNativeJdbcExtractor
NativeJdbcExtractor
NativeJdbcExtractorAdapter
SimpleNativeJdbcExtractor
WebLogicNativeJdbcExtractor
WebSphereNativeJdbcExtractor
XAPoolNativeJdbcExtractor