spring 事务注意事项 -- 事务注解一定写到service最外层

事务采用的是注解方式。持久层用的是MyBatis，简单配置如下：

<!--数据源配置, 使用 Druid 数据库连接池-->
<bean id="mysqlDataSource" class="com.alibaba.druid.pool.DruidDataSource"  destroy-method="close">
<qualifier value="dataSource"/>
<!-- 基本属性 url、user、password -->
<property name="url" value="${mysql.database.url}"/>
<property name="username" value="${mysql.database.user}"/>
<property name="password" value="${mysql.database.password}"/>

<!-- 配置初始化大小、最小、最大 -->
<property name="initialSize" value="5"/>
<property name="minIdle" value="${mysql.database.minIdle}"/>
<property name="maxActive" value="${mysql.database.maxActive}"/>

<!-- 配置获取连接等待超时的时间 -->
<property name="maxWait" value="60000"/>

<!-- 配置间隔多久才进行一次检测，检测需要关闭的空闲连接，单位是毫秒 -->
<property name="timeBetweenEvictionRunsMillis" value="60000"/>

<!-- 配置一个连接在池中最小生存的时间，单位是毫秒 -->
<property name="minEvictableIdleTimeMillis" value="300000"/>

<property name="validationQuery" value="SELECT 1 FROM DUAL" />
<property name="testWhileIdle" value="true"/>
<property name="testOnBorrow" value="false"/>
<property name="testOnReturn" value="false"/>

<!-- 配置监控统计拦截的filters -->
<property name="filters" value="stat"/>
</bean>

<!-- mybatis文件配置，扫描所有mapper文件 -->
<bean id="sqlSessionFactory" class="org.mybatis.spring.SqlSessionFactoryBean">
<property name="dataSource" ref="mysqlDataSource"/>
<property name="typeAliasesPackage" value="com.xxxxx.model"/>
<property name="configLocation" value="classpath:/conf/mybatis/mybatis-config.xml"/>
<!-- 自动扫描映射文件 -->
<property name="mapperLocations">
<list>
<value>classpath:/mappers/*.xml</value>
</list>
</property>
</bean>

<!-- spring与mybatis整合配置，扫描所有dao -->
<!-- 扫描basePackage下所有以@MyBatisRepository注解的接口-->
<bean class="org.mybatis.spring.mapper.MapperScannerConfigurer">
<property name="sqlSessionFactoryBeanName" value="sqlSessionFactory"/>
<property name="basePackage" value="com.xxxxx.dao"/>
</bean>

<!-- mysqlServer事务，注意 使用此事务时需要显示写明Transaction(value="txMysqlManager")-->
<bean id="txMysqlManager"  class="org.springframework.jdbc.datasource.DataSourceTransactionManager">
<property name="dataSource" ref="mysqlDataSource" />
</bean>

<!-- 事务控制   -->
<!-- mysqlServer事务，注意 使用此事务时需要显示写明Transaction(value="txMysqlManager")-->
<tx:annotation-driven transaction-manager="txMysqlManager" proxy-target-class="true" order="50"/>

controller代码如下：

@RequestMapping(value="/testTransaction", method={RequestMethod.GET, RequestMethod.POST})
public  void  testTransaction() {
try {
ybsTrainingService.commitTransactionBase();
} catch (Exception e) {

logger.info("测试内容失败", e);

}
}

servce代码如下：

@Transactional(value = "txMysqlManager", rollbackFor = Exception.class)
public void commitTransactionBase() {
commitTransaction();
}
private void commitTransaction() {
TrainingState trainingState = new TrainingState();

trainingState.setTrainingId(220);

trainingState.setTrainingState(1); //数据库上是3trainingMapper.updateTrainingState(ybsTrainingState);CourseState ybsCourseState = new CourseState();courseState.setCourseState(1); //数据库上是2 courseState.setId(9348172);courseMapper.updateCourseState(ybsCourseState); //如下两行是异常测试 ，会报空指针异常

ybsCourseState = null;
ybsCourseState.setCourseState(1);
}

注意：如果将 “@Transactional(value ="txMysqlManager", rollbackFor = Exception.class)” 放到子方法commitTransaction()上边，如下，则事务不会起作用。

public void commitTransactionBase() {
commitTransaction();
}

@Transactional(value = "txMysqlManager", rollbackFor = Exception.class)
private void commitTransaction() {

TrainingState trainingState = new TrainingState();

trainingState.setTrainingId(220);

trainingState.setTrainingState(1); //数据库上是3

trainingMapper.updateTrainingState(ybsTrainingState);

CourseState ybsCourseState = new CourseState();

courseState.setCourseState(1);       //数据库上是2

courseState.setId(9348172);

courseMapper.updateCourseState(ybsCourseState);

//如下两行是异常测试 ，会报空指针异常

    ybsCourseState = null;ybsCourseState.setCourseState(1);

}补充，最外层service方法，在这里边是commitTransactionBase() 方法，就是被controller直接调用的。所以肯定是public 修饰，如果是私有private修饰 ，则事务也不会生效，当然正常情况下，controller也不会调用到其他类的private方法。