[轉]Spring 中的多數據源配置的問題

最近看到Spring 中的多數據源配置的問題，如下：

在SpringSide 3 中，白衣提供的預先配置好的環境非常有利於用戶進行快速開發，但是同時也會爲擴展帶來一些困難。最直接的例子就是關於在項目中使用多個數據源的問題，似乎很難搞。在上一篇中，我探討了SpringSide 3 中的數據訪問層，在這一篇中，我立志要解決多數據源配置的難題，我的思路是這樣的：

第一步、測試能否配置多個DataSource
第二步、測試能否配置多個SessionFactory
第三步、測試能否配置多個TransactionManager
第四步、測試能否使用多個TransactionManager，也就是看能否配置多個<tx:annotation-driven/>

基本上到第四步就應該走不通了，因爲Spring中似乎不能配置多個<tx:annotation-driven/>，而且@transactional註解也無法讓用戶選擇具體使用哪個TransactionManager。也就是說，在SpringSide的應用中，不能讓不同的數據源分別屬於不同的事務管理器，多數據源只能使用分佈式事務管理器，那麼測試思路繼續如下進行：

第五步、測試能否配置JTATransactionManager

如果到這一步，項目還能順利在Tomcat中運行的話，我們就算大功告成了。但我總認爲事情不會那麼順利，我總覺得JTATransactionManager需要應用服務器的支持，而且需要和JNDI配合使用，具體是不是這樣，那只有等測試後才知道。如果被我不幸言中，那麼進行下一步：

第六步、更換Tomcat爲GlassFish，更換JDBC的DataSource爲JNDI查找的DataSource，然後配置JTATransactionManager

下面測試開始，先假設場景，還是繼續用上一篇中提到的簡單的文章發佈系統，假設該系統運行一段時間後非常火爆，單靠一臺服務器已經無法支持巨大的用戶數，這時候，站長想到了把數據進行水平劃分，於是，需要建立一個索引數據庫，該索引數據庫需保存每一篇文章的Subject及其內容所在的Web服務器，而每一個Web服務器上運行的項目，需要同時訪問索引數據庫和內容數據庫。所以，需要創建索引數據庫，如下：

create database puretext_index;

use puretext_index;

create table articles(
id int primary key auto_increment,
subject varchar(256),
webserver varchar(30)
);

第一步測試，配置多個DataSource，配置文件如下：
application.properties：

jdbc.urlContent=jdbc:mysql://localhost:3306/PureText?useUnicode=true&characterEncoding=utf8
jdbc.urlIndex=jdbc:mysql://localhost:3306/PureText_Index?useUnicode=true&characterEncoding=utf8

applicationContext.xml：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:jee="http://www.springframework.org/schema/jee" xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-2.5.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd"
default-lazy-init="true">

<description>Spring公共配置文件 </description>


<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="systemPropertiesModeName" value="SYSTEM_PROPERTIES_MODE_OVERRIDE" />
<property name="ignoreResourceNotFound" value="true" />
<property name="locations">
<list>

<value>classpath*:/application.properties</value>

<value>classpath*:/application.local.properties</value>


</list>
</property>
</bean>


<context:component-scan base-package="cn.puretext" />


<bean id="dataSourceContent" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">

<property name="driverClassName" value="com.mysql.jdbc.Driver" />
<property name="url" value="${jdbc.urlContent}" />
<property name="username" value="${jdbc.username}" />
<property name="password" value="${jdbc.password}" />


<property name="initialSize" value="5" />
<property name="maxActive" value="100" />
<property name="maxIdle" value="30" />
<property name="maxWait" value="1000" />
<property name="poolPreparedStatements" value="true" />
<property name="defaultAutoCommit" value="false" />
</bean>
<bean id="dataSourceIndex" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">

<property name="driverClassName" value="com.mysql.jdbc.Driver" />
<property name="url" value="${jdbc.urlIndex}" />
<property name="username" value="${jdbc.username}" />
<property name="password" value="${jdbc.password}" />


<property name="initialSize" value="5" />
<property name="maxActive" value="100" />
<property name="maxIdle" value="30" />
<property name="maxWait" value="1000" />
<property name="poolPreparedStatements" value="true" />
<property name="defaultAutoCommit" value="false" />
</bean>





<bean id="sessionFactory" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
<property name="dataSource" ref="dataSourceContent" />
<property name="namingStrategy">
<bean class="org.hibernate.cfg.ImprovedNamingStrategy" />
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</prop>
<prop key="hibernate.show_sql">${hibernate.show_sql}</prop>
<prop key="hibernate.format_sql">${hibernate.format_sql}</prop>
<prop key="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider
</prop>
<prop key="hibernate.cache.provider_configuration_file_resource_path">${hibernate.ehcache_config_file}</prop>
</props>
</property>
<property name="packagesToScan" value="cn.puretext.entity.*" />
</bean>


<bean id="transactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactory" />
</bean>





<tx:annotation-driven transaction-manager="transactionManager" />
</beans>

這個時候運行上一篇文章中寫好的單元測試DaoTest.java，結果發現還是會出錯，錯誤原因如下：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'cn.puretext.unit.service.DaoTest': Autowiring of methods failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire method: public void org.springframework.test.context.junit4.AbstractTransactionalJUnit4SpringContextTests.setDataSource(javax.sql.DataSource); nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No unique bean of type [javax.sql.DataSource] is defined: expected single matching bean but found 2: [dataSourceContent, dataSourceIndex]

經過分析，發現是測試類的基類需要注入DataSource，而現在配置了多個DataSource，所以Spring不知道哪個DataSource匹配了，所以需要改寫DaoTest.java，如下：

package cn.puretext.unit.service;

import java.util.List;

import javax.annotation.Resource;
import javax.sql.DataSource;

import org.junit.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springside.modules.orm.Page;
import org.springside.modules.test.junit4.SpringTxTestCase;

import cn.puretext.dao.ArticleDao;
import cn.puretext.entity.web.Article;

public class DaoTest extends SpringTxTestCase {
@Autowired
private ArticleDao articleDao;

public ArticleDao getArticleDao() {
return articleDao;
}

public void setArticleDao(ArticleDao articleDao) {
this.articleDao = articleDao;
}

@Override
@Resource(name = "dataSourceContent")
public void setDataSource(DataSource dataSource) {
// TODO Auto-generated method stub
super.setDataSource(dataSource);
}

@Test
public void addArticle() {
Article article = new Article();
article.setSubject("article test");
article.setContent("article test");
articleDao.save(article);
}

@Test
public void pageQuery() {
Page<Article> page = new Page<Article>();
page.setPageSize(10);
page.setPageNo(2);
page = articleDao.getAll(page);
List<Article> articles = page.getResult();
}
}

改變的內容主要爲重寫了基類中的setDataSource方法，並使用@Resource註解指定使用的DataSource爲dataSourceContent。經過修改後，單元測試成功運行。

第二步，配置多個SessionFactory，配置文件如下：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:jee="http://www.springframework.org/schema/jee" xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-2.5.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd"
default-lazy-init="true">

<description>Spring公共配置文件 </description>


<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="systemPropertiesModeName" value="SYSTEM_PROPERTIES_MODE_OVERRIDE" />
<property name="ignoreResourceNotFound" value="true" />
<property name="locations">
<list>

<value>classpath*:/application.properties</value>

<value>classpath*:/application.local.properties</value>


</list>
</property>
</bean>


<context:component-scan base-package="cn.puretext" />


<bean id="dataSourceContent" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">

<property name="driverClassName" value="com.mysql.jdbc.Driver" />
<property name="url" value="${jdbc.urlContent}" />
<property name="username" value="${jdbc.username}" />
<property name="password" value="${jdbc.password}" />


<property name="initialSize" value="5" />
<property name="maxActive" value="100" />
<property name="maxIdle" value="30" />
<property name="maxWait" value="1000" />
<property name="poolPreparedStatements" value="true" />
<property name="defaultAutoCommit" value="false" />
</bean>
<bean id="dataSourceIndex" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">

<property name="driverClassName" value="com.mysql.jdbc.Driver" />
<property name="url" value="${jdbc.urlIndex}" />
<property name="username" value="${jdbc.username}" />
<property name="password" value="${jdbc.password}" />


<property name="initialSize" value="5" />
<property name="maxActive" value="100" />
<property name="maxIdle" value="30" />
<property name="maxWait" value="1000" />
<property name="poolPreparedStatements" value="true" />
<property name="defaultAutoCommit" value="false" />
</bean>





<bean id="sessionFactoryContent" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
<property name="dataSource" ref="dataSourceContent" />
<property name="namingStrategy">
<bean class="org.hibernate.cfg.ImprovedNamingStrategy" />
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</prop>
<prop key="hibernate.show_sql">${hibernate.show_sql}</prop>
<prop key="hibernate.format_sql">${hibernate.format_sql}</prop>
<prop key="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider
</prop>
<prop key="hibernate.cache.provider_configuration_file_resource_path">${hibernate.ehcache_config_file}</prop>
</props>
</property>
<property name="packagesToScan" value="cn.puretext.entity.*" />
</bean>
<bean id="sessionFactoryIndex" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
<property name="dataSource" ref="dataSourceIndex" />
<property name="namingStrategy">
<bean class="org.hibernate.cfg.ImprovedNamingStrategy" />
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</prop>
<prop key="hibernate.show_sql">${hibernate.show_sql}</prop>
<prop key="hibernate.format_sql">${hibernate.format_sql}</prop>
<prop key="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider
</prop>
<prop key="hibernate.cache.provider_configuration_file_resource_path">${hibernate.ehcache_config_file}</prop>
</props>
</property>
<property name="packagesToScan" value="cn.puretext.entity.*" />
</bean>


<bean id="transactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactoryContent" />
</bean>





<tx:annotation-driven transaction-manager="transactionManager" />
</beans>

運行單元測試，報錯，錯誤代碼如下：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'cn.puretext.unit.service.DaoTest': Autowiring of fields failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire field: private cn.puretext.dao.ArticleDao cn.puretext.unit.service.DaoTest.articleDao; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'articleDao': Autowiring of methods failed; nested exception is org.springframework.beans.factory.BeanCreationException: Could not autowire method: public void org.springside.modules.orm.hibernate.SimpleHibernateDao.setSessionFactory(org.hibernate.SessionFactory); nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException: No unique bean of type [org.hibernate.SessionFactory] is defined: expected single matching bean but found 2: [sessionFactoryContent, sessionFactoryIndex]

這和上面出現的錯誤是異曲同工的，只不過這次是ArticleDao類裏面不知道注入哪一個SessionFactory，因此，需要修改ArticleDao類，重寫setSessionFactory方法，並用@Resource註解指定，如下：

package cn.puretext.dao;

import javax.annotation.Resource;

import org.hibernate.SessionFactory;
import org.springframework.stereotype.Repository;
import org.springside.modules.orm.hibernate.HibernateDao;

import cn.puretext.entity.web.Article;

@Repository
public class ArticleDao extends HibernateDao<Article, Long> {

@Override
@Resource(name = "sessionFactoryContent")
public void setSessionFactory(SessionFactory sessionFactory) {
// TODO Auto-generated method stub
super.setSessionFactory(sessionFactory);
}

}

運行單元測試，成功。

第三步、配置多個TransactionManager，如下：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:jee="http://www.springframework.org/schema/jee" xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-2.5.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd"
default-lazy-init="true">

<description>Spring公共配置文件 </description>


<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="systemPropertiesModeName" value="SYSTEM_PROPERTIES_MODE_OVERRIDE" />
<property name="ignoreResourceNotFound" value="true" />
<property name="locations">
<list>

<value>classpath*:/application.properties</value>

<value>classpath*:/application.local.properties</value>


</list>
</property>
</bean>


<context:component-scan base-package="cn.puretext" />


<bean id="dataSourceContent" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">

<property name="driverClassName" value="com.mysql.jdbc.Driver" />
<property name="url" value="${jdbc.urlContent}" />
<property name="username" value="${jdbc.username}" />
<property name="password" value="${jdbc.password}" />


<property name="initialSize" value="5" />
<property name="maxActive" value="100" />
<property name="maxIdle" value="30" />
<property name="maxWait" value="1000" />
<property name="poolPreparedStatements" value="true" />
<property name="defaultAutoCommit" value="false" />
</bean>
<bean id="dataSourceIndex" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">

<property name="driverClassName" value="com.mysql.jdbc.Driver" />
<property name="url" value="${jdbc.urlIndex}" />
<property name="username" value="${jdbc.username}" />
<property name="password" value="${jdbc.password}" />


<property name="initialSize" value="5" />
<property name="maxActive" value="100" />
<property name="maxIdle" value="30" />
<property name="maxWait" value="1000" />
<property name="poolPreparedStatements" value="true" />
<property name="defaultAutoCommit" value="false" />
</bean>





<bean id="sessionFactoryContent" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
<property name="dataSource" ref="dataSourceContent" />
<property name="namingStrategy">
<bean class="org.hibernate.cfg.ImprovedNamingStrategy" />
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</prop>
<prop key="hibernate.show_sql">${hibernate.show_sql}</prop>
<prop key="hibernate.format_sql">${hibernate.format_sql}</prop>
<prop key="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider
</prop>
<prop key="hibernate.cache.provider_configuration_file_resource_path">${hibernate.ehcache_config_file}</prop>
</props>
</property>
<property name="packagesToScan" value="cn.puretext.entity.*" />
</bean>
<bean id="sessionFactoryIndex" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
<property name="dataSource" ref="dataSourceIndex" />
<property name="namingStrategy">
<bean class="org.hibernate.cfg.ImprovedNamingStrategy" />
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</prop>
<prop key="hibernate.show_sql">${hibernate.show_sql}</prop>
<prop key="hibernate.format_sql">${hibernate.format_sql}</prop>
<prop key="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider
</prop>
<prop key="hibernate.cache.provider_configuration_file_resource_path">${hibernate.ehcache_config_file}</prop>
</props>
</property>
<property name="packagesToScan" value="cn.puretext.entity.*" />
</bean>


<bean id="transactionManagerContent" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactoryContent" />
</bean>
<bean id="transactionManagerIndex" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactoryIndex" />
</bean>





<tx:annotation-driven transaction-manager="transactionManagerContent" />
</beans>

這個時候運行還是會出錯，出錯的原因爲 org.springframework.beans.factory.NoSuchBeanDefinitionException: No bean named 'transactionManager' is defined，因爲該出錯信息很短，我也難以找出究竟是哪個地方需要名爲“transactionManager”的事務管理器，改個名字都不行，看來Spring的自動注入有時候也錯綜複雜害人不淺。不過，如果把上面的其中一個名字改成“transactionManger”，另外一個名字不改，運行是成功的，如下：


<bean id="transactionManager" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactoryContent" />
</bean>
<bean id="transactionManagerIndex" class="org.springframework.orm.hibernate3.HibernateTransactionManager">
<property name="sessionFactory" ref="sessionFactoryIndex" />
</bean>

這個時候得出結論是，可以配置多個TransactionManager，但是必須有一個的名字是transactionManager。

第四步、配置多個<tx:annotation-driven/>，如下：


<tx:annotation-driven transaction-manager="transactionManager" />
<tx:annotation-driven transaction-manager="transactionManagerIndex" />

運行測試，天啦，竟然成功了。和我之前預料的完全不一樣，居然在一個配置文件中配置多個<tx:annotation-driven/>一點問題都沒有。那麼在使用@Transactional的地方，它真的能夠選擇正確的事務管理器嗎？我不得不寫更多的代碼來進行測試。那就針對索引數據庫中的表寫一個Entity，寫一個Dao測試一下吧。

代碼如下：

package cn.puretext.entity.web;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.Table;

import org.hibernate.annotations.Cache;
import org.hibernate.annotations.CacheConcurrencyStrategy;

import cn.puretext.entity.IdEntity;

@Entity
// 表名與類名不相同時重新定義表名.
@Table(name = "articles")
// 默認的緩存策略.
@Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
public class ArticleIndex extends IdEntity {
private String subject;
private String webServer;

public String getSubject() {
return subject;
}

public void setSubject(String subject) {
this.subject = subject;
}
@Column(name = "webserver")
public String getWebServer() {
return webServer;
}

public void setWebServer(String webServer) {
this.webServer = webServer;
}
}

package cn.puretext.dao;

import javax.annotation.Resource;

import org.hibernate.SessionFactory;
import org.springframework.stereotype.Repository;
import org.springside.modules.orm.hibernate.HibernateDao;

import cn.puretext.entity.web.ArticleIndex;

@Repository
public class ArticleIndexDao extends HibernateDao<ArticleIndex, Long> {
@Override
@Resource(name = "sessionFactoryIndex")
public void setSessionFactory(SessionFactory sessionFactory) {
// TODO Auto-generated method stub
super.setSessionFactory(sessionFactory);
}
}

package cn.puretext.unit.service;

import java.util.List;

import javax.annotation.Resource;
import javax.sql.DataSource;

import org.junit.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.transaction.annotation.Transactional;
import org.springside.modules.orm.Page;
import org.springside.modules.test.junit4.SpringTxTestCase;

import cn.puretext.dao.ArticleDao;
import cn.puretext.dao.ArticleIndexDao;
import cn.puretext.entity.web.Article;
import cn.puretext.entity.web.ArticleIndex;
import cn.puretext.service.ServiceException;

public class DaoTest extends SpringTxTestCase {
@Autowired
private ArticleDao articleDao;
@Autowired
private ArticleIndexDao articleIndexDao;

public void setArticleIndexDao(ArticleIndexDao articleIndexDao) {
this.articleIndexDao = articleIndexDao;
}

public void setArticleDao(ArticleDao articleDao) {
this.articleDao = articleDao;
}

@Override
@Resource(name = "dataSourceContent")
public void setDataSource(DataSource dataSource) {
// TODO Auto-generated method stub
super.setDataSource(dataSource);
}

@Test
@Transactional
public void addArticle() {
Article article = new Article();
article.setSubject("article test");
article.setContent("article test");
articleDao.save(article);
}

@Test
@Transactional
public void pageQuery() {
Page<Article> page = new Page<Article>();
page.setPageSize(10);
page.setPageNo(2);
page = articleDao.getAll(page);
List<Article> articles = page.getResult();
}

@Test
@Transactional
public void addIndex() {
ArticleIndex articleIndex = new ArticleIndex();
articleIndex.setSubject("test");
articleIndex.setWebServer("www001");
articleIndexDao.save(articleIndex);
}

@Test
@Transactional
public void addArticleAndAddIndex() {
addArticle();
addIndex();
throw new ServiceException("測試事務回滾");
}
}

運行測試，結果還是成功的。到目前，發現在一個項目中使用多個TransactionManager可以正常運行，但是有兩個問題需要考慮：
1、爲什麼必須得有一個TransactionManager名字爲transactionManager？
2、這兩個TransactionManager真的能正常工作嗎？
3、OpenSessionInView的問題怎麼解決？

以上的三個問題在單元測試中是不能找出答案的，我只好再去寫Action層的代碼，期望能夠從中得到線索。經過一天艱苦的努力，終於真相大白：
1、並不是必須有一個TransactionManager的名字爲transactionMananger，這只是單元測試在搞鬼，在真實的Web環境中，無論兩個TransactionManager取什麼名字都可以，運行不會報錯。所以這個答案很明確，是因爲單元測試的基類需要一個名爲 transactionMananger的事務管理器。
2、在單元測試中，只能測試Dao類和Entity類能否正常工作，但是由於單元測試結束後事務會自動回滾，不會把數據寫入到數據庫中，所以沒有辦法確定兩個TransactionManager能否正常工作。在真實的Web環境中，問題很快就浮出水面，只有一個數據庫中有數據，另外一個數據庫中沒有，經過調整<tx:annotation-driven/>的位置並對比分析，發現只有放在前面的TransactionMananger的事務能夠正常提交，放在後面的TransactionManager的事務不能提交，所以永遠只有一個數據庫裏面有數據。
3、如果早一點脫離單元測試而進入真實的Web環境，就會早一點發現OpenSessionInViewFilter的問題，因爲只要配置多個 SessionFactory，運行的時候OpenSessionInViewFilter就會報錯。爲了解決這個問題，我只能去閱讀 OpenSessionInViewFilter的源代碼，發現它在將Session綁定到線程的時候用的是Map，而且使用 SessionFactory作爲Map的key，這就說明在線程中綁定多個Session不會衝突，也進一步說明可以在web.xml中配置多個 OpenSessionInViewFilter。而我也正是通過配置多個OpenSessionInViewFilter來解決問題的。我的 web.xml文件如下：

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4" xmlns="http://java.sun.com/xml/ns/j2ee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd">

<display-name>PureText</display-name>

<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath*:/applicationContext*.xml</param-value>
</context-param>


<filter>
<filter-name>encodingFilter</filter-name>
<filter-class>org.springframework.web.filter.CharacterEncodingFilter</filter-class>
<init-param>
<param-name>encoding</param-name>
<param-value>UTF-8</param-value>
</init-param>
<init-param>
<param-name>forceEncoding</param-name>
<param-value>true</param-value>
</init-param>
</filter>

<filter>
<filter-name>hibernateOpenSessionInViewFilterContent</filter-name>
<filter-class>org.springside.modules.orm.hibernate.OpenSessionInViewFilter</filter-class>
<init-param>
<param-name>excludeSuffixs</param-name>
<param-value>js,css,jpg,gif</param-value>
</init-param>
<init-param>
<param-name>sessionFactoryBeanName</param-name>
<param-value>sessionFactoryContent</param-value>
</init-param>
</filter>
<filter>
<filter-name>hibernateOpenSessionInViewFilterIndex</filter-name>
<filter-class>org.springside.modules.orm.hibernate.OpenSessionInViewFilter</filter-class>
<init-param>
<param-name>excludeSuffixs</param-name>
<param-value>js,css,jpg,gif</param-value>
</init-param>
<init-param>
<param-name>sessionFactoryBeanName</param-name>
<param-value>sessionFactoryIndex</param-value>
</init-param>
</filter>

<filter>
<filter-name>springSecurityFilterChain</filter-name>
<filter-class>org.springframework.web.filter.DelegatingFilterProxy</filter-class>
</filter>


<filter>
<filter-name>struts2Filter</filter-name>
<filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
</filter>

<filter-mapping>
<filter-name>encodingFilter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>

<filter-mapping>
<filter-name>springSecurityFilterChain</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<filter-mapping>
<filter-name>hibernateOpenSessionInViewFilterContent</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<filter-mapping>
<filter-name>hibernateOpenSessionInViewFilterIndex</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>
<filter-mapping>
<filter-name>struts2Filter</filter-name>
<url-pattern>/*</url-pattern>
</filter-mapping>


<listener>
<listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
</listener>


<listener>
<listener-class>org.springframework.web.util.IntrospectorCleanupListener</listener-class>
</listener>


<session-config>
<session-timeout>20</session-timeout>
</session-config>


<error-page>
<exception-type>java.lang.Throwable</exception-type>
<location>/common/500.jsp</location>
</error-page>
<error-page>
<error-code>500</error-code>
<location>/common/500.jsp</location>
</error-page>
<error-page>
<error-code>404</error-code>
<location>/common/404.jsp</location>
</error-page>
<error-page>
<error-code>403</error-code>
<location>/common/403.jsp</location>
</error-page>
</web-app>
經過上面的分析，發現使用多個TransactionManager是不可行的（這個時候我在想，也許不使用Annotation就可以使用多個 TransactionMananger吧，畢竟Spring的AOP應該是可以把不同的TransactionManager插入到不同的類和方法中，但是誰願意走回頭路呢？畢竟都已經是@Transactional的年代了），雖然運行不會報錯，但是隻有一個TransactionManager的事務能夠正常提交。所以測試進入下一步：

第五步、使用JTATransactionManager

簡單地修改配置文件，使用JTATransactionManager做爲事務管理器，配置文件我就不列出來了，運行，結果抱錯，錯誤信息如下：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name '_filterChainProxy': Initialization of bean failed; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name '_filterChainList': Cannot create inner bean '(inner bean)' of type [org.springframework.security.config.OrderedFilterBeanDefinitionDecorator$OrderedFilterDecorator] while setting bean property 'filters' with key [10]; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name '(inner bean)': Cannot resolve reference to bean 'filterSecurityInterceptor' while setting constructor argument; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'filterSecurityInterceptor' defined in file [D:\Temp\1-PureText\WEB-INF\classes\applicationContext-security.xml]: Cannot resolve reference to bean 'databaseDefinitionSource' while setting bean property 'objectDefinitionSource'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'databaseDefinitionSource': FactoryBean threw exception on object creation; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'org.springframework.transaction.interceptor.TransactionInterceptor#0': Cannot resolve reference to bean 'transactionManager' while setting bean property 'transactionManager'; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'transactionManager' defined in file [D:\Temp\1-PureText\WEB-INF\classes\applicationContext.xml]: Invocation of init method failed; nested exception is java.lang.IllegalStateException: No JTA UserTransaction available - specify either 'userTransaction' or 'userTransactionName' or 'transactionManager' or 'transactionManagerName'

通過分析，發現其中最關鍵的一句是No JTA UserTransaction available，看來，我們只能進入到第六步，使用GlassFish了。

第六步、將項目部署到GlassFish中

將項目簡單地部署到GlassFish中之後，項目可以成功運行，沒有報錯，說明JTA UserTransaction問題解決了，但是檢查數據庫卻發現依然沒有數據，看來JTATransactionManager不僅要和應用服務器配合使用，還要和JNDI數據源一起使用。將數據源的配置修改爲JNDI後，問題解決。下面是我的配置文件：

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:jee="http://www.springframework.org/schema/jee" xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:context="http://www.springframework.org/schema/context"
xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-2.5.xsd http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee-2.5.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd"
default-lazy-init="true">

<description>Spring公共配置文件 </description>


<bean class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="systemPropertiesModeName" value="SYSTEM_PROPERTIES_MODE_OVERRIDE" />
<property name="ignoreResourceNotFound" value="true" />
<property name="locations">
<list>

<value>classpath*:/application.properties</value>

<value>classpath*:/application.local.properties</value>


</list>
</property>
</bean>


<context:component-scan base-package="cn.puretext" />


<jee:jndi-lookup id="dataSourceContent" jndi-name="jdbc/dataSourceContent" />
<jee:jndi-lookup id="dataSourceIndex" jndi-name="jdbc/dataSourceIndex" />


<bean id="sessionFactoryContent" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
<property name="dataSource" ref="dataSourceContent" />
<property name="namingStrategy">
<bean class="org.hibernate.cfg.ImprovedNamingStrategy" />
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</prop>
<prop key="hibernate.show_sql">${hibernate.show_sql}</prop>
<prop key="hibernate.format_sql">${hibernate.format_sql}</prop>
<prop key="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider
</prop>
<prop key="hibernate.cache.provider_configuration_file_resource_path">${hibernate.ehcache_config_file}</prop>
</props>
</property>
<property name="packagesToScan" value="cn.puretext.entity.*" />
</bean>
<bean id="sessionFactoryIndex" class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
<property name="dataSource" ref="dataSourceIndex" />
<property name="namingStrategy">
<bean class="org.hibernate.cfg.ImprovedNamingStrategy" />
</property>
<property name="hibernateProperties">
<props>
<prop key="hibernate.dialect">org.hibernate.dialect.MySQL5InnoDBDialect</prop>
<prop key="hibernate.show_sql">${hibernate.show_sql}</prop>
<prop key="hibernate.format_sql">${hibernate.format_sql}</prop>
<prop key="hibernate.cache.provider_class">org.hibernate.cache.EhCacheProvider
</prop>
<prop key="hibernate.cache.provider_configuration_file_resource_path">${hibernate.ehcache_config_file}</prop>
</props>
</property>
<property name="packagesToScan" value="cn.puretext.entity.*" />
</bean>






<bean id="transactionManager" class="org.springframework.transaction.jta.JtaTransactionManager" />


<tx:annotation-driven transaction-manager="transactionManager" />

</beans>
最後，我得出的結論是：要想使用多個數據庫，就必須使用JTATransactionMananger，必須使用GlassFish等應用服務器而不是Tomcat，必須使用JNDI來管理dataSource。

如果一定要使用Tomcat呢？

這確實是一個難題，但是並不代表着沒有解決辦法。經過廣泛的Google一番之後，終於發現了一個好東東，那就是JOTM，它的全稱就是Java Open Transaction Mananger，它的作用就是可以單獨提供JTA事務管理的功能，不需要應用服務器。JOTM的使用方法有兩種，一種就是把它配置到項目中，和 Spring結合起來使用，另外一種就是把它配置到Tomcat中，這時，Tomcat搖身一變就成了和GlassFish一樣的能夠提供JTA功能的服務器了。

JOTM的官方網站爲http://jotm.ow2.org，這是它的新網站，舊網站爲http://jotm.objectweb.org。

我選擇了把JOTM 2.0.11整合到Tomcat中的方法進行了測試，結果發現還是不能夠正常運行，我使用的是JOTM2.0.11，Tomcat 6.0.20，JKD 6 Update10。看來還得繼續折騰下去了。

另外一個開源的JTA事務管理器是Atomikos，它供了事務管理和連接池，不需要應用服務器支持，其官方網站爲http://www.atomikos.com/。有興趣的朋友可以試試。

很佩服這位兄弟的專研精神

我是這樣配置多數據源的：比如兩個數據源，mysql使用：

<aop:config proxy-target-class="true">
<aop:advisor pointcut="execution(* com.mysqlservice..*.*(..))" advice-ref="txAdvice_2"/>
</aop:config>

<tx:advice id="txAdvice_2" transaction-manager="mysqltransactionManager">
<tx:attributes>
<tx:method name="save*" propagation="REQUIRED" rollback-for="java.lang.Exception"/>
<tx:method name="update*" propagation="REQUIRED" rollback-for="java.lang.Exception"/>
<tx:method name="delete*" propagation="REQUIRED" rollback-for="java.lang.Exception"/>
<tx:method name="*" read-only="true" propagation="SUPPORTS"/>
</tx:attributes>
</tx:advice>
在oracle中使用 @Transactional ，配置如下：


<tx:annotation-driven transaction-manager="oracleTransactionManager" />
這種方式就可以在SPRING下對兩個數據源進行管理，現在我的系統跑的很正常

各位兄弟有沒有好的建議，大家都說出來討論一下，共同研究哈

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