DTP模型之二：（XA协议之二）jotm分布式事务实现

分布式事务是指操作多个数据库之间的事务，spring的org.springframework.transaction.jta.JtaTransactionManager，提供了分布式事务支持。如果使用WAS的JTA支持，把它的属性改为WebSphere对应的TransactionManager。 
    在tomcat下，是没有分布式事务的，不过可以借助于第三方软件jotm（Java Open Transaction Manager ）和AtomikosTransactionsEssentials实现，在spring中分布式事务是通过jta（jotm，atomikos）来进行实现。 
1、http://jotm.objectweb.org/ 
2、http://www.atomikos.com/Main/TransactionsEssentials 

一、使用JOTM例子 
(1)、Dao及实现

public interface GenericDao {  
  
    public int save(String ds, String sql, Object[] obj) throws Exception;  
      
    public int findRowCount(String ds, String sql);  
      
}

public class GenericDaoImpl implements GenericDao{  
  
    private  JdbcTemplate jdbcTemplateA;  
    private  JdbcTemplate jdbcTemplateB;  
  
    public void setJdbcTemplateA(JdbcTemplate jdbcTemplate) {  
        this.jdbcTemplateA = jdbcTemplate;  
    }  
  
    public void setJdbcTemplateB(JdbcTemplate jdbcTemplate) {  
        this.jdbcTemplateB = jdbcTemplate;  
    }  
      
    public int save(String ds, String sql, Object[] obj) throws Exception{  
        if(null == ds || "".equals(ds)) return -1;  
        try{  
            if(ds.equals("A")){  
                return this.jdbcTemplateA.update(sql, obj);  
            }else{  
                return this.jdbcTemplateB.update(sql, obj);  
            }  
        }catch(Exception e){  
            e.printStackTrace();  
            throw new Exception("执行" + ds + "数据库时失败！");  
        }  
    }  
  
    public int findRowCount(String ds, String sql) {  
        if(null == ds || "".equals(ds)) return -1;  
          
        if(ds.equals("A")){  
            return this.jdbcTemplateA.queryForInt(sql);  
        }else{  
            return this.jdbcTemplateB.queryForInt(sql);  
        }  
    }  
  
}

(2)、Service及实现 

public interface UserService {  
      
    public void saveUser() throws Exception;  
      
} 

public class UserServiceImpl implements UserService{  
  
    private GenericDao genericDao;  
      
    public void setGenericDao(GenericDao genericDao) {  
        this.genericDao = genericDao;  
    }  
  
    public void saveUser() throws Exception {  
        String userName = "user_" + Math.round(Math.random()*10000);  
        System.out.println(userName);  
          
        StringBuilder sql = new StringBuilder();  
        sql.append(" insert into t_user(username, gender) values(?,?); ");  
        Object[] objs = new Object[]{userName,"1"};  
          
        genericDao.save("A", sql.toString(), objs);  
          
        sql.delete(0, sql.length());  
        sql.append(" insert into t_user(name, sex) values(?,?); ");  
        objs = new Object[]{userName,"男的"};//值超出范围  
        genericDao.save("B", sql.toString(), objs);  
    }  
  
} 

(3)、applicationContext-jotm.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:context="http://www.springframework.org/schema/context"   
    xmlns:aop="http://www.springframework.org/schema/aop"   
    xmlns:tx="http://www.springframework.org/schema/tx"   
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-2.5.xsd   
    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-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/aop http://www.springframework.org/schema/aop/spring-aop-2.5.xsd">  
  
    <description>springJTA</description>  
  
    <!--指定Spring配置中用到的属性文件-->   
    <bean id="propertyConfig"   
            class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">   
        <property name="locations">   
            <list>   
                <value>classpath:jdbc.properties</value>   
            </list>   
        </property>   
    </bean>   
      
    <!-- JOTM实例 -->  
    <bean id="jotm" class="org.springframework.transaction.jta.JotmFactoryBean">  
          <property name="defaultTimeout" value="500000"/>  
    </bean>  
  
    <!-- JTA事务管理器 -->  
    <bean id="jtaTransactionManager" class="org.springframework.transaction.jta.JtaTransactionManager">     
        <property name="userTransaction" ref="jotm" />     
    </bean>  
  
    <!-- 数据源A -->   
    <bean id="dataSourceA" class="org.enhydra.jdbc.pool.StandardXAPoolDataSource" destroy-method="shutdown">   
       <property name="dataSource">   
           <bean class="org.enhydra.jdbc.standard.StandardXADataSource" destroy-method="shutdown">   
               <property name="transactionManager" ref="jotm"/>   
               <property name="driverName" value="${jdbc.driver}"/>   
               <property name="url" value="${jdbc.url}"/>   
           </bean>   
       </property>   
       <property name="user" value="${jdbc.username}"/>   
       <property name="password" value="${jdbc.password}"/>   
    </bean>   
  
    <!-- 数据源B -->   
    <bean id="dataSourceB" class="org.enhydra.jdbc.pool.StandardXAPoolDataSource" destroy-method="shutdown">   
       <property name="dataSource">   
           <bean class="org.enhydra.jdbc.standard.StandardXADataSource" destroy-method="shutdown">   
               <property name="transactionManager" ref="jotm"/>   
               <property name="driverName" value="${jdbc2.driver}"/>   
               <property name="url" value="${jdbc2.url}"/>   
           </bean>   
       </property>   
       <property name="user" value="${jdbc2.username}"/>   
       <property name="password" value="${jdbc2.password}"/>   
    </bean>   
  
    <bean id = "jdbcTemplateA"   
         class = "org.springframework.jdbc.core.JdbcTemplate">   
         <property name = "dataSource" ref="dataSourceA"/>   
    </bean>  
      
    <bean id = "jdbcTemplateB"   
         class = "org.springframework.jdbc.core.JdbcTemplate">   
         <property name = "dataSource" ref="dataSourceB"/>   
    </bean>      
  
    <!-- 事务切面配置 -->   
    <aop:config>   
        <aop:pointcut id="pointCut"  
                expression="execution(* com.logcd.service..*.*(..))"/><!-- 包及其子包下的所有方法 -->  
        <aop:advisor pointcut-ref="pointCut" advice-ref="txAdvice"/>   
          
        <aop:advisor pointcut="execution(* *..common.service..*.*(..))" advice-ref="txAdvice"/>  
    </aop:config>   
  
    <!-- 通知配置 -->   
    <tx:advice id="txAdvice" transaction-manager="jtaTransactionManager">   
       <tx:attributes>   
          <tx:method name="delete*" rollback-for="Exception"/>   
          <tx:method name="save*" rollback-for="Exception"/>   
          <tx:method name="update*" rollback-for="Exception"/>   
          <tx:method name="find*" read-only="true" rollback-for="Exception"/>   
       </tx:attributes>   
    </tx:advice>   
  
    <bean id="genericDao"   
            class="com.logcd.dao.impl.GenericDaoImpl" autowire="byName">  
    </bean>  
  
    <bean id="userService"   
            class="com.logcd.service.impl.UserServiceImpl" autowire="byName">  
    </bean>  
  
</beans> 

 (4)、测试 

public class TestUserService{  
  
    private static UserService userService;  
      
    @BeforeClass  
    public static void init(){  
        ApplicationContext app = new ClassPathXmlApplicationContext("applicationContext-jotm.xml");  
        userService = (UserService)app.getBean("userService");  
    }  
      
    @Test  
    public void save(){  
        System.out.println("begin...");  
        try{  
            userService.saveUser();  
        }catch(Exception e){  
            System.out.println(e.getMessage());  
        }  
        System.out.println("finish...");  
    }  
      
}

二、关于使用atomikos实现
(1)、数据源配置

<bean id="dataSourceA" class="com.atomikos.jdbc.SimpleDataSourceBean" init-method="init" destroy-method="close">  
    <property name="uniqueResourceName">  
        <value>${datasource.uniqueResourceName}</value>  
    </property>  
    <property name="xaDataSourceClassName">   
        <value>${database.driver_class}</value>   
    </property>   
    <property name="xaDataSourceProperties">  
        <value>URL=${database.url};user=${database.username};password=${database.password}</value>   
    </property>   
    <property name="exclusiveConnectionMode">   
        <value>${connection.exclusive.mode}</value>   
    </property>  
    <property name="connectionPoolSize">   
        <value>${connection.pool.size}</value>  
    </property>  
    <property name="connectionTimeout">  
        <value>${connection.timeout}</value>  
    </property>  
    <property name="validatingQuery">   
        <value>SELECT 1</value>   
    </property>   
</bean>

(2)、事务配置 

<bean id="atomikosTransactionManager" class="com.atomikos.icatch.jta.UserTransactionManager"   
    init-method="init" destroy-method="close">   
    <property name="forceShutdown" value="true"/>   
</bean>   
  
<bean id="atomikosUserTransaction" class="com.atomikos.icatch.jta.UserTransactionImp">   
    <property name="transactionTimeout" value="${transaction.timeout}"/>   
</bean>  
  
<!-- JTA事务管理器 -->   
<bean id="springTransactionManager" class="org.springframework.transaction.jta.JtaTransactionManager">   
    <property name="transactionManager" ref="atomikosTransactionManager"/>   
    <property name="userTransaction" ref="atomikosUserTransaction"/>   
</bean>  
  
<!-- 事务切面配置 -->   
<aop:config>   
    <aop:pointcut id="serviceOperation"  expression="execution(* *..service*..*(..))"/>   
    <aop:advisor pointcut-ref="serviceOperation" advice-ref="txAdvice"/>   
</aop:config>  
  
<!-- 通知配置 -->  
<tx:advice id="txAdvice" transaction-manager="springTransactionManager">   
    <tx:attributes>  
        <tx:method name="*" rollback-for="Exception"/>   
    </tx:attributes>   
</tx:advice>