Ibatis + Spring 操作 Blob 详解

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iBATIS Spring Bean JDBC Oracle

一：Java工程环境介绍

(1) 工程目录结构

(2) Oracle9i + Oracle10g的驱动 + jdk1.4

(3) 用到的jar包如下：

(4) 数据库表结构

create table IBATIS_BLOB
(
ID      VARCHAR2(5) not null,
TITLE   VARCHAR2(50),
CONTENT BLOB
)

二：主要代码如下

(1) IbatisBlob.java

package cn.com.victorysoft.vo;

public class IbatisBlob {
private String id;
private String title;
private byte[] content;
public String getId() {
return id;
}
public void setId(String id) {
this.id = id;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public byte[] getContent() {
return content;
}
public void setContent(byte[] content) {
this.content = content;
}
}

(2) ibatisblob-sqlmap.xml

<sqlMap namespace="ibatisblob">
<typeAlias alias="ibatisblob" type="cn.com.victorysoft.vo.IbatisBlob" />
<select id="getIbatisBlobById" parameterClass="ibatisblob" resultClass="ibatisblob">
select * from IBATIS_BLOB where
<dynamic prepend=" ">
<isNotNull prepend="and" property="id">
     id = #id#
</isNotNull>
</dynamic>
</select>
<insert id="insert" parameterClass="ibatisblob">
<selectKey resultClass="string" keyProperty="id">
   select IBATISBLOB_SQ.nextval as id from dual
</selectKey>
insert into IBATIS_BLOB(id,content,title) values(#id#,#content:BLOB#,#title#)
</insert>
<insert id="update" parameterClass="ibatisblob">
update IBATIS_BLOB set title = #title# ,content= #content:BLOB#
where id = #id#
</insert>
</sqlMap>

(3) SqlMapConfig.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE sqlMapConfig PUBLIC "-//ibatis.apache.org//DTD SQL Map Config 2.0//EN"
    "http://ibatis.apache.org/dtd/sql-map-config-2.dtd">
<sqlMapConfig>
<settings cacheModelsEnabled="true" enhancementEnabled="true"
lazyLoadingEnabled="true" errorTracingEnabled="true" maxRequests="32"
maxSessions="10" maxTransactions="5" useStatementNamespaces="false" />

<typeHandler jdbcType="BLOB" javaType="[B" callback="org.springframework.orm.ibatis.support.BlobByteArrayTypeHandler" />
<sqlMap
resource="cn/com/victorysoft/sqlmap/ibatisblob-sqlmap.xml" />
</sqlMapConfig>

说明：红色部分为处理BLOB 类型的TypeHandler 实现类。

(4) beans.xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE beans PUBLIC "-//SPRING//DTD BEAN 2.0//EN" "http://www.springframework.org/dtd/spring-beans-2.0.dtd">
<beans>

<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
    <property name="driverClassName">
      <value>oracle.jdbc.driver.OracleDriver</value>
    </property>
    <property name="url">
      <value>jdbc:oracle:thin:@localhost:1521:ora</value>
    </property>
    <property name="username">
      <value>test</value>
    </property>
    <property name="password">
      <value>test</value>
    </property>
</bean>
<bean id="transactionManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource">
   <ref bean="dataSource"/>
</property>
</bean>
<bean id="transactionManagerRootProxy" class="org.springframework.transaction.interceptor.TransactionProxyFactoryBean" abstract="true">
<property name="transactionManager">
   <ref bean="transactionManager"/>
</property>
<property name="proxyTargetClass">
   <value>false</value>
</property>
<property name="transactionAttributes">
   <props>
    <prop key="insert*">PROPAGATION_REQUIRED,-Exception</prop>

    <prop key="update*">PROPAGATION_REQUIRED,-Exception</prop>
    <prop key="select*">PROPAGATION_REQUIRED,readOnly</prop>
   </props>
</property>
</bean>
<bean id="nativeJdbcExtractor" class="org.springframework.jdbc.support.nativejdbc.CommonsDbcpNativeJdbcExtractor" lazy-init="true" />
    <bean id="oracleLobHandler" class="org.springframework.jdbc.support.lob.OracleLobHandler" lazy-init="true">
     <property name="nativeJdbcExtractor">
         <ref local="nativeJdbcExtractor" />
     </property>
</bean>
<bean id="sqlMapClient" class="org.springframework.orm.ibatis.SqlMapClientFactoryBean">
<property name="configLocation" value="SqlMapConfig.xml"/>
<property name="dataSource" ref="dataSource"/>
<property name="lobHandler">
         <ref local="oracleLobHandler"/>
     </property>
</bean>
<bean id="dataAccess" class="cn.com.victorysoft.dataaccess.impl.DataAccess">
   <property name="sqlMapClient" ref="sqlMapClient"/>
</bean>
<bean id="batisBlobDAOSub" class="cn.com.victorysoft.dao.impl.IBatisBlobDAOImpl">
   <property name="dataAccess" ref="dataAccess"/>
</bean>
<bean id="batisBlobDAO" parent="transactionManagerRootProxy">
<property name="target">
   <ref bean="batisBlobDAOSub" />
</property>
</bean>
</beans>

说明：Spring对LOB的支持是在事务的环境中，所以操作LOB的DAO必须受事务的管理。如果不放在事务的环境中，会报如下异常：

Caused by: java.lang.IllegalStateException: Spring transaction synchronization needs to be active for setting values

(5) 测试类代码 MainTest.java

package cn.com.victorysoft.test;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.util.FileCopyUtils;
import cn.com.victorysoft.dao.IBatisBlobDAO;
import cn.com.victorysoft.vo.IbatisBlob;

public class MainTest {
public static void main(String[] args) throws Exception {
ApplicationContext ctx = new ClassPathXmlApplicationContext("beans.xml");
IBatisBlobDAO batisBlobDAO = (IBatisBlobDAO)ctx.getBean("batisBlobDAO");
//****************插入图片开始*************
IbatisBlob batisBlob = new IbatisBlob();
batisBlob.setTitle("mytitle");
File file = new File("d:/dd.jpg");
FileInputStream fis = new FileInputStream(file);
        byte[] b = FileCopyUtils.copyToByteArray(fis);
        batisBlob.setContent(b);
        batisBlobDAO.insertIbaisBlob(batisBlob);
        fis.close();
        //****************插入图片结束*************
        //****************更新图片开始*************
        batisBlob.setId("1");
        batisBlob.setTitle("gengxin");
        File updateFile = new File("d:/dd.jpg");
        FileInputStream updateFis = new FileInputStream(updateFile);
        byte[] ub = FileCopyUtils.copyToByteArray(updateFis);
        batisBlob.setContent(ub);
        batisBlobDAO.updateIbaisBlob(batisBlob);
        //****************更新图片结束*************
        //***************查询图片并输出************
        batisBlob.setId("1");
        batisBlob = batisBlobDAO.selectIbaisBlobById(batisBlob);
        byte[] bb = batisBlob.getContent();
        File outFile = new File("d:/cwb.jpg");
        FileOutputStream sout = new FileOutputStream(outFile);
        sout.write(bb);
        sout.flush();
        sout.close();
        //***************查询图片并结束************
}

}

说明：本类对BLOB字段的插入、修改、查询做了测试，无任何问题，均可以正确执行。

其中FileCopyUtils为Spring提供的工具类，它提供了许多一步式的静态操作方法，能够将文件内容拷贝到一个目标 byte[]、String 甚至一个输出流或输出文件中。使用起来十分方便。

本文来自CSDN博客，转载请标明出处：http://blog.csdn.net/cwb1128/archive/2009/07/12/4342141.aspx