Nutz DAO与spring集成讨论

关注Nutz已经有段时间了，一直没有时间仔细研究Nutz。这几天抽空研究了下Nutz DAO部分，总体上觉得Nutz的质量令人振奋，Nutz DAO部分也非常好用。

    目前个人觉得Nutz DAO在事务管理方面设计得不够好，有待改进，可以参考Nutz 网站上本人提的Issue（http://code.google.com/p/nutz/issues/detail?id=162）。主要的问题是：事务控制的代码和业务逻辑代码耦合在一起。解决的方法应该大致有两种：

    1、通过Issue中讨论的，采用@Tran注解；

    2、和Ioc部分配合，采用声明式事物管理；

    个人更喜欢声明式事物管理方式，而spring提供了非常好的声明式事物管理方案，所以在这里主要讨论下Nutz DAO和spring集成的细节问题。
    Nutz DAO和spring集成也有两种方式：

    1、采用spring的Ioc，但是事务还是采用Nutz自己管理控制；

    2、采用spring的声明式事务管理控制；

    接下来我们仔细讨论下这两种方式。

    方式1：方式1非常简单，Nutz DAO不需要做任何修改即能完成，你可以在你的项目的spring配置文件中添加如下配置即可：

<!-- the DataSource -->
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://127.0.0.1:3306/zdtest"/>
<property name="username" value="root"/>
<property name="password" value="root"/>
</bean>
<!-- Nutz DAO -->
<bean id="dao" class="org.nutz.dao.impl.NutDao">
<property name="dataSource" ref="dataSource"/>
</bean>
<!-- your service object that refer to the Nutz DAO -->
<bean id="petService" class="cn.zj.pubinfo.nutz.pet.PetService">
<property name="dao" ref="dao"/>
</bean>

    这种模式下，spring只提供了Ioc，事务还是有Nutz自己管理和控制。
    方式2：
    我们要在spring中声明事务管理，大致可以如下：

<!-- Nutz DAO -->
<bean id="dao" class="org.nutz.dao.impl.NutDao">
<property name="dataSource" ref="dataSource"/>
</bean>
<bean id="petDao" class="cn.zj.pubinfo.nutz.pet.PetDao">
<property name="dao" ref="dao"/>
</bean>
<!-- this is the service object that we want to make transactional -->
<bean id="petService" class="cn.zj.pubinfo.nutz.pet.PetService">
<property name="petDao" ref="petDao"/>
</bean>
<!-- the transactional advice (what 'happens'; see the <aop:advisor/> bean below) -->
<tx:advice id="txAdvice" transaction-manager="txManager">
<!-- the transactional semantics... -->
<tx:attributes>
<!-- all methods starting with 'get' are read-only -->
<tx:method name="get*" read-only="true"/>
<!-- other methods use the default transaction settings (see below) -->
<tx:method name="*"/>
</tx:attributes>
</tx:advice>
<!-- ensure that the above transactional advice runs for any execution
of an operation defined by the FooService interface -->
<aop:config>
<aop:pointcut id="petServiceOperation" expression="execution(* cn.zj.pubinfo.nutz.pet.PetService.*(..))"/>
<aop:advisor advice-ref="txAdvice" pointcut-ref="petServiceOperation"/>
</aop:config>
<!-- don't forget the DataSource -->
<bean id="dataSource" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://127.0.0.1:3306/zdtest"/>
<property name="username" value="root"/>
<property name="password" value="root"/>
</bean>
<!-- similarly, don't forget the PlatformTransactionManager -->
<bean id="txManager" class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="dataSource"/>
</bean>
<!-- other <bean/> definitions here -->

    然后，我们对org.nutz.dao.impl.NutDao进行必要的修改，把NutDao中的run()方法：

	public void run(ConnCallback callback) {
ConnectionHolder ch = Daos.getConnection(getDataSource());
try {
ch.invoke(callback);
}
catch (Throwable e) {
try {
ch.rollback();
}
catch (SQLException e1) {}
if (e instanceof RuntimeException)
throw (RuntimeException) e;
else
throw new RuntimeException(e);
}
finally {
Daos.releaseConnection(ch);
}
}

    修改为：

	import org.springframework.jdbc.datasource.DataSourceUtils;
public void run(ConnCallback callback) {
Connection con = DataSourceUtils.getConnection(getDataSource());
try {
callback.invoke(con);
} catch (Exception e) {
if (e instanceof RuntimeException)
throw (RuntimeException) e;
else
throw new RuntimeException(e);
} finally {
DataSourceUtils.releaseConnection(con, getDataSource());
}
}

    OK，运行一下测试，得到如下日志，事务成功的日志：

2010-04-30 13:12:33,498 [main] DEBUG org.springframework.jdbc.datasource.DataSourceTransactionManager - Creating new transaction with name [cn.zj.pubinfo.nutz.pet.IPetService.createTwoCat]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT
2010-04-30 13:12:33,498 [main] DEBUG org.springframework.jdbc.datasource.DataSourceTransactionManager - Acquired Connection [jdbc:mysql://127.0.0.1:3306/zdtest, UserName=root@localhost, MySQL-AB JDBC Driver] for JDBC transaction
2010-04-30 13:12:33,499 [main] DEBUG org.springframework.jdbc.datasource.DataSourceTransactionManager - Switching JDBC Connection [jdbc:mysql://127.0.0.1:3306/zdtest, UserName=root@localhost, MySQL-AB JDBC Driver] to manual commit
2010-04-30 13:12:33,499 [main] DEBUG org.nutz.dao.impl.NutDao - INSERT INTO t_pet(age,name) VALUES( 0, 'Cat 1')
2010-04-30 13:12:33,500 [main] DEBUG org.nutz.dao.impl.NutDao - SELECT MAX(id) FROM t_pet
2010-04-30 13:12:33,501 [main] DEBUG org.nutz.dao.impl.NutDao - INSERT INTO t_pet(age,name) VALUES( 0, 'Cat 2')
2010-04-30 13:12:33,501 [main] DEBUG org.nutz.dao.impl.NutDao - SELECT MAX(id) FROM t_pet
2010-04-30 13:12:33,502 [main] DEBUG org.springframework.jdbc.datasource.DataSourceTransactionManager - Initiating transaction commit
2010-04-30 13:12:33,502 [main] DEBUG org.springframework.jdbc.datasource.DataSourceTransactionManager - Committing JDBC transaction on Connection [jdbc:mysql://127.0.0.1:3306/zdtest, UserName=root@localhost, MySQL-AB JDBC Driver]
2010-04-30 13:12:33,529 [main] DEBUG org.springframework.jdbc.datasource.DataSourceTransactionManager - Releasing JDBC Connection [jdbc:mysql://127.0.0.1:3306/zdtest, UserName=root@localhost, MySQL-AB JDBC Driver] after transaction
2010-04-30 13:12:33,529 [main] DEBUG org.springframework.jdbc.datasource.DataSourceUtils - Returning JDBC Connection to DataSource

    事务失败的日志：

2010-04-30 13:15:17,438 [main] DEBUG org.springframework.jdbc.datasource.DataSourceTransactionManager - Creating new transaction with name [cn.zj.pubinfo.nutz.pet.IPetService.createTwoCat]: PROPAGATION_REQUIRED,ISOLATION_DEFAULT
2010-04-30 13:15:17,439 [main] DEBUG org.springframework.jdbc.datasource.DataSourceTransactionManager - Acquired Connection [jdbc:mysql://127.0.0.1:3306/zdtest, UserName=root@localhost, MySQL-AB JDBC Driver] for JDBC transaction
2010-04-30 13:15:17,439 [main] DEBUG org.springframework.jdbc.datasource.DataSourceTransactionManager - Switching JDBC Connection [jdbc:mysql://127.0.0.1:3306/zdtest, UserName=root@localhost, MySQL-AB JDBC Driver] to manual commit
2010-04-30 13:15:17,440 [main] DEBUG org.nutz.dao.impl.NutDao - INSERT INTO t_pet(age,name) VALUES( 0, 'Cat 1')
2010-04-30 13:15:17,440 [main] DEBUG org.nutz.dao.impl.NutDao - SELECT MAX(id) FROM t_pet
2010-04-30 13:15:17,441 [main] DEBUG org.nutz.dao.impl.NutDao - INSERT INTO t_pet(age,name) VALUES( 0, 'Cat 2')
2010-04-30 13:15:17,442 [main] DEBUG org.nutz.dao.impl.NutDao - SELECT MAX(id) FROM t_pet
2010-04-30 13:15:17,442 [main] DEBUG org.springframework.jdbc.datasource.DataSourceTransactionManager - Initiating transaction rollback
2010-04-30 13:15:17,442 [main] DEBUG org.springframework.jdbc.datasource.DataSourceTransactionManager - Rolling back JDBC transaction on Connection [jdbc:mysql://127.0.0.1:3306/zdtest, UserName=root@localhost, MySQL-AB JDBC Driver]
2010-04-30 13:15:17,465 [main] DEBUG org.springframework.jdbc.datasource.DataSourceTransactionManager - Releasing JDBC Connection [jdbc:mysql://127.0.0.1:3306/zdtest, UserName=root@localhost, MySQL-AB JDBC Driver] after transaction
2010-04-30 13:15:17,465 [main] DEBUG org.springframework.jdbc.datasource.DataSourceUtils - Returning JDBC Connection to DataSource
java.lang.RuntimeException: 测试Nutz DAO和spring集成事务回滚异常
at cn.zj.pubinfo.nutz.pet.PetService.createTwoCat(PetService.java:35)
......

    日志表明，并查询了数据库证明，spring声明式事物工作正常。